United States
Environmental Protection
Agency
Robert S Kerr Environmental Research EPA 600 2 79 151
Laboratory August 1979
Ada OK 74820
Research and Development
Wastewater
Irrigation at
Tallahassee, Florida
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7 Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution-sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-79-151
August 1979
WASTEWATER IRRIGATION AT TALLAHASSEE, FLORIDA
by
Allen R. Overman
University of Florida
Gainesville, Florida 32611
Project S800829
Project Officer
Lowell E. Leach
Robert S. Kerr Environmental Research Laboratory
U.S. Environmental Protection Agency
Ada, Oklahoma 74820
ROBERT S. KERR ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
ADA, OKLAHOMA 74820
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DISCLAIMER
This report has been reviewed by the Robert S. Kerr Environmental
Research Laboratory, U.S. Environmental Protection Agency, and approved for
publication. Approval does not signify that the contents necessarily reflect
the views and policies of the U.S. Environmental Protection Agency, nor does
mention of trade names or commercial products constitute endorsement or
recommendation for use.
11
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FOREWORD
The Environmental Protection Agency was established to coordinate
administration of the major Federal programs designed to protect the
quality of our environment.
An important part of the agency's effort involves the search for
information about environmental problems, management techniques and new
technologies through which optimum use of the nation's land and water
resources can be assured and the threat pollution poses to the welfare of
the American people can be minimized.
EPA's Office of Research and Development conducts this search through
a nationwide network of research facilities.
As one of these facilities, the Robert S. Kerr Environmental Research
Laboratory is responsible for the management of programs to: (a) investi-
gate the nature, transport, fate and management of pollutants in ground-
water; (b) develop and demonstrate methods for treating wastewaters with
soil and other natural systems; (c) develop and demonstrate pollution
control technologies for irrigation return flows; (d) develop and demon-
strate pollution control technologies for animal production wastes;
(e) develop and demonstrate technologies to prevent, control or abate
pollution from the petroleum refining and petrochemical industries; and
(f) develop and demonstrate technologies to manage pollution resulting from
combinations of industrial wastewaters or industrial/municipal wastewaters.
This report contributes to the knowledge essential if the EPA is to
meet the requirements of environmental laws that it establish and enforce
pollution control standards which are reasonable, cost effective and
provide adequate protection for the American public.
William C. Galegar
Director
Robert S. Kerr Environmental Research Laboratory
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ABSTRACT
Effluent from a secondary treatment plant was applied to crops on Lake-
land fine sand at Tallahassee, Florida. Summer crops included coastal bermuda-
grass, sorghum x sudangrass, pearl millet, corn and kenaf at irrigation rates
up to 200 millimeters (mm)/week [8 inches (in.)/week]. Winter crops included
rye and ryegrass at irrigation rates up to 100 mm/week (4 in./week). Yields
and nutrient uptake increased with application rate, while recovery efficiency
decreased. Nitrogen recovery above 50% required rates in the range of 25-50
mm/week (1-2 in./week).
Test wells in the 200 mm/week plots did show N03-N levels above 10 milli-
grams/liter (mg/1). Results of this work and a companion study by the U.S.
Geological Survey showed mixing and dilution in the groundwater. The soil was
very effective in removing fecal coliform bacteria and BOD from the percolating
effluent.
Field studies showed that nitrification was essentially complete in the
upper 120 centimeters (cm) [4 feet (ft)] of soil. Phosphorus removal within
this same depth exceeded 99%, and complete removal was obtained before reach-
ing the water table some 12-15 meters (m) (35-45 ft) below ground surface.
Soil pH remained in the vicinity of 6.5.
A model of cation transport showed that surface exchange was linearly
coupled with flow velocity. Good description of transport in a packed-bed
reactor was obtained for the NHt/K+ system.
A model of phosphorus transport showed that at low velocities surface
exchange was diffusion limited, while at higher velocities surface kinetics
was controlling. The model described transport in a packed-bed reactor quite
well.
A model of phosphorus kinetics was developed using Langmuir-Hinshelwood
kinetics for the heterogeneous process. It also included a homogeneous
reaction. Effects of pH and soil/solution ratio in a batch reactor were
accounted for. The relevant species of phosphate ion was identified as
H2PO~.
This report was submitted in fulfillment of Grant No. S800829 by the
University of Florida, Agricultural Engineering Department, under the sponsor-
ship of the U.S. Environmental Protection Agency. This report covers the
period April 1, 1971, to December 1, 1978.
IV
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CONTENTS
Foreword iii
Abstract iv
Figures „ . vi
Tables „ xiii
Acknowledgments xx
1. Introduction 1
2. Conclusions 3
3. Recommendations 4
4. Site Description 5
5. System Characteristics 15
6. Crop Yields and Growth Response 40
7. Analysis of Transport Processes .... 143
References 179
Appendix 186
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FIGURES
Number Page
1 General Location of Study Site 6
2 Detailed Location of Study Site 7
3 Layout of Irrigation System and Field Plots 8
4 Distribution of pH in Field Plots 23
5 Distribution of K in Field Plots 24
6 Distribution of Na in Field Plots 25
7 Distribution of Ca in Field Plots 26
8 Distribution of Mg in Field Plots 27
9 Distribution of Total Extractable Bases in Field Plots .... 28
10 Distribution of Extractable Bases in Field Plots 29
11 Distribution of Base Exchange Fraction in Field Plots 30
12 Distribution of Extractable P in Field Plots 33
13 Distribution of Solution P Under Steady Irrigation 34
14 Distribution of NH4~N and N03-N Under Steady Irrigation .... 35
15 Estimated Yield Response of Coastal Bermudagrass 43
16 Estimated Nitrogen Recovery by Coastal Bermudagrass 44
17 Estimated Phosphorus Recovery by Coastal Bermudagrass 45
18 Estimated Potassium Recovery by Coastal Bermudagrass 46
19 Estimated Calcium Recovery by Coastal Bermudagrass 47
20 Estimated Magnesium Recovery by Coastal Bermudagrass 48
21 Estimated Sodium Recovery by Coastal Bermudagrass 49
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Number Page
22 Estimated Iron Recovery by Coastal Bermudagrass 50
23 Estimated Zinc Recovery by Coastal Bermudagrass 51
24 Estimated Yield Response of Sorghum x Sudangrass 53
25 Estimated Nitrogen Recovery by Sorghum x Sudangrass 54
26 Estimated Phosphorus Recovery by Sorghum x Sudangrass 55
27 Estimated Potassium Recovery by Sorghum x Sudangrass 56
28 Estimated Calcium Recovery by Sorghum x Sudangrass ...... 57
29 Estimated Magnesium Recovery by Sorghum x Sudangrass ..... 58
30 Estimated Sodium Recovery by Sorghum x Sudangrass ....... 59
31 Estimated Iron Recovery by Sorghum x Sudangrass 60
32 Estimated Zinc Recovery by Sorghum x Sudangrass , 61
33 Estimated Yield Response of Pearl Millet 62
34 Estimated Nitrogen Recovery by Pearl Millet ..... 63
35 Estimated Phosphorus Recovery by Pearl Millet . 64
36 Estimated Potassium Recovery by Pearl Millet 65
37 Estimated Calcium Recovery by Pearl Millet . 66
38 Estimated Magnesium Recovery by Pearl Millet 67
39 Estimated Sodium Recovery by Pearl Millet 68
40 Estimated Iron Recovery by Pearl Millet 69
41 Estimated Zinc Recovery by Pearl Millet 70
42 Estimated Yield Response of Corn Silage ..... 72
43 Estimated Nitrogen Recovery by Corn Silage 73
44 Estimated Phosphorus Recovery by Corn Silage 74
45 Estimated Potassium Recovery by Corn Silage .... 75
46 Estimated Calcium Recovery by Corn Silage 76
VII
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Number Pa9e
47 Estimated Magnesium Recovery by Corn Silage 77
48 Estimated Sodium Recovery by Corn Silage 78
49 Estimated Iron Recovery by Corn Silage 79
50 Estimated Zinc Recovery by Corn Silage 80
51 Estimated Yield Response by Corn Grain 81
52 Estimated Nitrogen Recovery by Corn Grain 82
53 Estimated Phosphorus Recovery by Corn Grain 83
54 Estimated Potassium Recovery by Corn Grain 84
55 Estimated Calcium Recovery by Corn Grain 85
56 Estimated Magnesium Recovery by Corn Grain 86
57 Estimated Sodium Recovery by Corn Grain 87
58 Estimated Iron Recovery by Corn Grain 88
59 Estimated Zinc Recovery by Corn Grain 89
60 Estimated Yield Response o^ Kenaf 91
61 Estimated Nitrogen Recovery by Kenaf 92
62 Estimated Phosphorus Recovery by Kenaf 93
63 Estimated Potassium Recovery by Kenaf 94
64 Estimated Calcium Recovery by Kenaf 95
65 Estimated Magnesium Recovery by Kenaf 96
66 Estimated Sodium Recovery by Kenaf 97
67 Estimated Iron Recovery by Kenaf 98
68 Estimated Zinc Recovery by Kenaf 99
69 Estimated Yield Response of Rye 100
70 Estimated Nitrogen Recovery by Rye 101
71 Estimated Phosphorus Recovery by Rye 102
vi i i
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Number Page
72 Estimated Potassium Recovery by Rye 103
73 Estimated Calcium Recovery by Rye 104
74 Estimated Magnesium Recovery by Rye 105
75 Estimated Sodium Recovery by Rye 106
76 Estimated Iron Recovery by Rye 107
77 Estimated Zinc Recovery by Rye , 108
78 Estimated Yield Response of Ryegrass , . , 109
79 Estimated Nitrogen Recovery by Ryegrass 110
80 Estimated Phosphorus Recovery by Ryegrass Ill
81 Estimated Potassium Recovery by Ryegrass , . . . . 112
82 Estimated Calcium Recovery by Ryegrass . , . . , 113
83 Estimated Magnesium Recovery by Ryegrass , . . , , 114
84 Estimated Sodium Recovery by Ryegrass 115
85 Estimated Iron Recovery by Ryegrass , , . 116
86 Estimated Zinc Recovery by Ryegrass , . . , 117
87 Response of Nitrogen Content, Dry Weight and Nitrogen
Recovery for Corn (Pioneer 3369A) ,.,..,. 122
88 Response of Nitrogen Content, Dry Weight and Nitrogen
Recovery for Corn (McNair 440V) 127
89 Response of Nitrogen Content, Dry Weight and Nitrogen
Recovery for Sorghum x Sudangrass 131
90 Response of Nitrogen Content, Dry Weight and Nitrogen
Recovery for Kenaf , 135
91 Growth Response of Cottonwood, Sycamore and Black Locust
to Effluent Irrigation 139
92 Growth Response of Green Ash, Chinese Elm and Tulip Poplar
to Effluent Irrigation 140
93 Growth Response of Sweetgum, Bald Cypress and Red Cedar
to Effluent Irrigation 141
ix
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Number
94 Growth Response of Loblolly Pine to Effluent
Irrigation 142
95 Steady State Distributions of Phosphorus for the
Packed Bed Reactor 147
96 Dependence of Reaction, Exchange and Dispersion
Coefficients on Velocity for the Equilibrium
Model of Phosphorus Transport 148
97 Dependence of Adsorption, Desorption and Reaction
Coefficients on Velocity for the Kinetic Model of
Phosphorus Transport , 154
98 Effect of Soil Mass on Steady State Phosphorus
Fixation in the Batch Reactor , 160
99 Dependence on Maximum Phosphorus Fixation Rate
on Soil Mass , 161
100 Dependence on Equilibrium Constant of Phosphorus
Fixation on Soil Mass n^0
I QL.
101 Effect of pH on Steady State Phosphorus Fixation
in the Batch Reactor 164
102 Dependence of Maximum Phosphorus Fixation Rate
on pH 165
103 Dependence of Equilibrium Constant for Phosphorus
Fixation on pH . . . . , 166
104 Effect of Solution Reaction on Steady State Phosphorus
Fixation in a Batch Reactor 168
105 Typical Outflow Curves for NHl/K+ Transport in a
Packed Bed Reactor 172
106 Dependence of Exchange and Dispersion Coefficients
on Velocity for NH^/K+ Transport 174
107 Lag Between Surface and Solution Concentration for
NH^/K+ Transport 175
108 Effect of Feed Concentration on Outflow Curves
for NHJ/K+ Transport 176
109 Effect of Ionic Strength on Exchange Coefficient and
Cation Exchange Capacity for NH+/K+ Transport 177
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Number Page
A-l Nitrogen Recovery by Sorghum x Sudangrass - 1971 190
A-2 Nitrogen Recovery by Kenaf - 1971 196
A-3 Nitrogen Recovery by Rye - 1971 199
A-4 Nitrogen Recovery by Ryegrass - 1971 201
A-5 Nitrogen Recovery by Sorghum x Sudangrass With Single
Applications - 1972 204
A-6 Nitrogen Recovery by Sorghum x Sudangrass With Split
Applications - 1972 212
A-7 Nitrogen Recovery by Kenaf With Single
Applications - 1972 215
A-8 Nitrogen Recovery by Kenaf With Split
Applications - 1972 218
A-9 Nitrogen Recovery by Corn Grain With Single
Applications - 1972 221
A-10 Nitrogen Recovery by Corn Grain With Split
Applications - 1972 224
A-ll Nitrogen Recovery by Corn Silage With Single
Applications - 1972 ....". " 227
A-l2 Nitrogen Recovery by Corn Silage With Split
Applications - 1972 . . . . ". 230
A-l3 Nitrogen Recovery by Pearl Millet - 1972 235
A-14 Nitrogen Recovery by Rye - 1972 238
A-l5 Nitrogen Recovery by Ryegrass - 1972 241
A-l6 Nitrogen Recovery by Sorghum x Sudangrass - 1973 247
A-l7 Nitrogen Recovery by Kenaf - 1973 250
A-l8 Nitrogen Recovery by Pearl Millet - 1973 255
A-19 Nitrogen Recovery by Corn Silage in 90 cm Rows - 1973 ..... 258
A-20 Nitrogen Recovery by Corn Silage in 45 cm Rows - 1973 261
A-21 Nitrogen Recovery by Corn Grain in 90 cm Rows - 1973 ..... 264
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Number Page
A-22 Nitrogen Recovery by Rye - 1973 272
A-23 Nitrogen Recovery by Ryegrass - 1973 279
A-24 Nitrogen Recovery by Pearl Millet (Gahi-1) - 1974 287
A-25 Nitrogen Recovery by Pearl Millet (Tiflate) - 1974 290
A-26 Nitrogen Recovery by Corn Silage - 1974 293
A-27 Nitrogen Recovery by Coastal Bermudagrass - 1974 299
A-28 Nitrogen Recovery by Rye - 1974 304
A-29 Nitrogen Recovery by Ryegrass - 1974 309
A-30 Nitrogen Recovery by Coastal Bermudagrass - 1975 317
xn
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TABLES
Number Page
1 Conversions from Metric to English Units 2
2 Lithologic Log of Calibration Well at the Treatment Plant ... 10
3 Lithologic Log of Background Well 13
4 Characteristics of Lakeland Sand Near the Irrigation Site ... 14
5 BOD and Solids Content of the Wastewater 15
6 Chemical Characteristics of the Secondary Effluent 17
7 Chemical Characteristics of the Background Well 18
8 Chemical Characteristics of the Field Well 18
9 Chemical Characteristics of the Coastal Bermudagrass Well ... 19
10 Average Chemical Characteristics of Effluent
and Various Wells 19
11 Characteristics of Soil Extracts - March 1971 21
12 Characteristics of Soil Extracts - October 1971 21
13 Characteristics of Soil Extracts - March 1972 22
14 Extractable Bases 22
15 Distribution of Basic Cations Between Adsorbed
and Solution Phases 31
16 Climatological Data for Tallahassee - 1971 37
17 Climatological Data for Tallahassee - 1972 37
18 Climatological Data for Tallahassee 1973 38
19 Climatological Data for Tallahassee - 1974 38
20 Climatological Data for Tallahassee - 1975 39
xm
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Number
21 Climatological Data for Tallahassee - 1976 39
22 Crops Grown Under Effluent Irrigation at
Tallahassee, Florida 40
23 Crops and Varieties Used in Growth Study 119
24 Irrigation Schedule for Growth Study 119
25 Growth Response of Corn (Pioneer 3369A) at 50 ran/week 120
26 Growth Response of Corn (Pioneer 3369A) at 100 mm/week .... 120
27 Growth Response of Corn (Pioneer 3369A) at 150 mm/week .... 121
28 Growth Response of Corn (Pioneer 3369A) at 200 mm/week .... 121
29 Estimated Yield and Nitrogen Response of Corn (Pioneer 3369A)
at 50 and 200 mm/week 123
30 Estimated Nitrogen Recovery by Corn (Pioneer 3369A)
at 50 and 200 mm/week 123
31 Growth Response of Corn (McNair 440V) at 50 mm/week 125
32 Growth Response of Corn (McNair 440V) at 100 mm/week 125
33 Growth Response of Corn (McNair 440V) at 150 mm/week 126
34 Growth Response of Corn (McNair 440V) at 200 mm/week 126
35 Estimated Yield and Nitrogen Response of Corn (McNair 440V)
at 50 and 200 mm/week 128
36 Estimated Nitrogen Recovery by Corn (McNair 440V)
at 50 and 200 mm/week 128
37 Growth Response of Sorghum x Sudangrass at 50 mm/week ..... 129
38 Growth Response of Sorghum x Sudangrass at 100 mm/week .... 129
39 Growth Response of Sorghum x Sudangrass at 150 mm/week .... 130
40 Growth Response of Sorghum x Sudangrass at 200 mm/week .... 130
41 Estimated Yield and Nitrogen Response of Sorghum x
Sudangrass at 50 and 200 mm/week 132
42 Estimated Nitrogen Recovery by Sorghum x Sudangrass
at 50 and 200 mm/week 132
xiv
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Number Page
43 Growth Response of Kenaf at 50 mm/week 133
44 Growth Response of Kenaf at TOO nun/week 133
45 Growth Response of Kenaf at 150 mm/week 134
46 Growth Response of Kenaf at 200 nun/week 134
47 Estimated Yield and Nitrogen Response of Kenaf
at 50 and 200 mm/week 136
48 Estimated Nitrogen Recovery by Kenaf at 50 and 200 mm/week , , 136
49 Estimated Harvest Age for Maximum Nitrogen Recovery 137
50 Species in Tree Study 138
51 Values of Rate Coefficients and Characteristic Times
at 2 cm Depth 156
A-l Field Schedule for Summer 1971 ..... 186
A-2 Yield and Dry Matter of Sorghum x Sudangrass - 1971 . 187
A-3 Nutrient Composition of Sorghum x Sudangrass - 1971 ...... 188
A-4 Nutrient Uptake by Sorghum x Sudangrass - 1971 189
A-5 Nutrient Recovery by Sorghum x Sudangrass - 1971 ....... 191
A-6 Yield and Dry Matter of Kenaf - 1971 , 192
A-7 Nutrient Composition of Kenaf - 1971 193
A-8 Nutrient Uptake by Kenaf - 1971 ......... 194
A-9 Nutrient Recovery by Kenaf - 1971 195
A-10 Yield and Composition of Rye - 1971 196
A-ll Nutrient Recovery by Rye - 1971 ................ 198
A-12 Yield and Composition of Ryegrass - 1971 200
A-l3 Nutrient Recovery by Ryegrass - 1971 ,,.,.,,. 200
A-14 Field Schedule for Summer 1972 202
A-15 Schedule for Split Applications 203
xv
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Number Pa9e
A-16 Yield and Dry Matter of Sorghum x Sudangrass with
Single Applications - 1972 203
A-17 Nutrient Composition of Sorghum x Sudangrass with
Single Applications - 1972 205
A-18 Nutrient Uptake by Sorghum x Sudangrass with
Single Applications - 1972 206
A-19 Nutrient Recovery by Sorghum x Sudangrass with
Single Applications - 1972 207
A-20 Yield and Dry Matter of Sorghum x Sudangrass with
Single Applications - 1972 208
A-21 Nutrient Composition of Sorghum x Sudangrass with
Split Applications - 1972 209
A-22 Nutrient Uptake by Sorghum x Sudangrass with
Split Applications - 1972 210
A-23 Nutrient Recovery by Sorghum x Sudangrass with
Split Applications - 1972 211
A-24 Yield and Composition of Kenaf with Single
Applications - 1972 213
A-25 Nutrient Recovery by Kenaf with Single
Applications - 1972 214
A-26 Yield and Composition of Kenaf with Split
Applications - 1972 216
A-27 Nutrient Recovery by Kenaf with Split
Applications 1972 217
A-28 Yield and Composition of Corn Grain with Single
Applications - 1972
219
A-29 Nutrient Recovery by Corn Grain with Single
Applications - 1972 220
A-30 Yield and Composition of Corn Grain with Split
Applications - 1972 222
A-31 Nutrient Recovery by Corn Grain with Split
Applications - 1972 223
A-32 Yield and Composition of Corn Silage with Single
Applications - 1972 225
xv i
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Number Page
A-33 Nutrient Recovery by Corn Silage with Single
Applications - 1972 226
A-34 Yield and Composition of Corn Silage with Split
Applications - 1972 - 228
A-35 Nutrient Recovery by Corn Silage with Split
Applications - 1972 229
A-36 Yield and Dry Matter of Pearl Millet - 1972 231
A-37 Nutrient Composition of Pearl Millet - 1972 232
A-38 Nutrient Uptake by Pearl Millet - 1972 233
A-39 Nutrient Recovery by Pearl Millet - 1972 234
A-40 Yield and Composition of Rye - 1972 236
A-41 Nutrient Recovery by Rye - 1972 237
A-42 Yield and Composition of Ryegrass 239
A-43 Nutrient Recovery by Ryegrass - 1972 240
A-44 Field Schedule for Summer 1973 242
A-45 Yield and Dry Matter of Sorghum x Sudangrass - 1973 243
A-46 Nutrient Composition of Sorghum x Sudangrass - 1973 244
A-47 Nutrient Uptake by Sorghum x Sudangrass - 1973 ... 245
A-48 Nutrient Recovery by Sorghum x Sudangrass - 1973 246
A-49 Yield and Composition of Kenaf - 1973 248
A-50 Nutrient Recovery by Kenaf - 1973 249
A-51 Yield and Dry Matter of Pearl Millet (Gahi-1) - 1973 251
A-52 Nutrient Composition of Pearl Millet (Gahi-1) - 1973 252
A-53 Nutrient Uptake by Pearl Millet (Gahi-1) - 1973 253
A-54 Nutrient Recovery by Pearl Millet (Gahi-1) - 1973 254
A-55 Yield and Composition of Corn Silage in 90 cm Rows - 1973 ... 256
A-56 Nutrient Recovery by Corn Silage in 90 cm Rows - 1973 .... 257
xvi i
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Number Pa9e
A-57 Yield and Composition of Corn Silage in 45 cm Rows - 1973 ... 259
A-58 Nutrient Recovery by Corn Silage in 45 cm Rows - 1973 260
A-59 Yield and Composition of Corn Grain in 90 cm Rows - 1973 ... 262
A-60 Nutrient Recovery by Corn Grain in 90 cm Rows - 1973 263
A-61 Field Schedule for Winter 1973 265
A-62 Yield and Dry Matter of Rye - 1973 266
A-63 Nutrient Content of Rye - 1973 267
A-64 Nutrient Uptake of Rye - 1973 269
A-65 Nutrient Recovery of Rye - 1973 271
A-66 Yield and Dry Matter of Ryegrass - 1973 273
A-67 Nutrient Content of Ryegrass - 1973 274
A-68 Nutrient Uptake of Ryegrass - 1973 276
A-69 Nutrient Recovery of Ryegrass - 1973 278
A-70 Field Schedule for Summer 1974 281
A-71 Yield and Dry Matter of Pearl Millet (Gahi-1) - 1974 281
A-72 Nutrient Composition of Pearl Millet (Gahi-1) - 1974 282
A-73 Nutrient Uptake of Pearl Millet (Gahi-1) - 1974 284
A-74 Nutrient Recovery by Pearl Millet (Gahi-1) - 1974 , . 286
A-75 Yield and Composition of Pearl Millet (Tiflate) - 1974 .... 288
A-76 Nutrient Recovery by Pearl Millet (Tiflate) - 1974 289
A-77 Yield and Composition of Corn Silage - 1974 291
A-78 Nutrient Recovery by Corn Silage - 1974 , 292
A-79 Yield and Dry Matter of Coastal Bermudagrass - 1974 294
A-80 Nutrient Content of Coastal Bermudagrass - 1974 295
A-81 Nutrient Uptake by Coastal Bermudagrass - 1974 297
xvm
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Number Page
A-82 Nutrient Recovery by Coastal Bermudagrass - 1974 298
A-83 Yield and Dry Matter of Rye - 1974 300
A-84 Nutrient Content of Rye - 1974 301
A-85 Nutrient Uptake of Rye - 1974 302
A-86 Nutrient Recovery of Rye - 1974 303
A-87 Yield and Dry Matter of Ryegrass - 1974 305
A-88 Nutrient Content of Ryegrass - 1974 306
A-89 Nutrient Uptake by Ryegrass - 1974 307
A-90 Nutrient Recovery by Ryegrass - 1974 308
A-91 Harvest Schedule for Summer 1975 310
A-92 Yield and Dry Matter of Coastal Bermudagrass (Plots) - 1975 . . 311
A-93 Nutrient Content of Coastal Bermudagrass (Plots) - 1975 .... 312
A-94 Nutrient Uptake by Coastal Bermudagrass (Plots) - 1975 314
A-95 Nutrient Recovery by Coastal Bermudagrass (Plots) - 1975 .... 316
A-96 Yield and Composition of Coastal Bermudagrass (Strip) 1975 . . 318
A-97 Nutrient Uptake by Coastal Bermudagrass (Strip) - 1975 319
A-98 Nutrient Recovery by Coastal Bermudagrass (Strip) - 1975 .... 319
xix
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ACKNOWLEDGMENTS
Many persons contributed to the progress of this study. Mr, Thomas P.
Smith, Director of Underground Utilities, City of Tallahassee, began the
effluent irrigation system at Tallahassee in 1966 and encouraged expanded
research on its performance, beginning in 1971. He provided much support
for this work and stimulated a lot of discussion on the subject in Florida.
All of the field and laboratory measurements were conducted jointly with
Mr. William G. Leseman, Director, Tallahassee Water Quality Laboratory. We
learned the art and science of waste treatment together. Mr. Alfred Nguy
served as laboratory assistant for the project and worked closely with
Mr. Leseman and his staff.
Ms. Rolan Chu and Mr. Brian McMahon conducted the experiments and wrote
computer programs for the studies on rate processes. The three of us, along
with Mr. Leseman and Mr. Nguy, held many intensive discussions about chemical
kinetics and transport processes.
Mr. Jack Woodard, Florida Department of Natural Resources, Tallahassee,
provided assistance with installation of test wells for the field study.
Dr. Glenn W. Burton, Plant Geneticist, Coastal Plains Experiment Station,
Tifton, Georgia, provided seeds for Tiflate pearl millet and encouraged the
forage studies.
Dr. Willis Chapman, Director of the University of Florida Agricultural
Research and Education Center, Quincy, Florida, kindly made a forage harvester
and other equipment available on several occasions.
Mr. Richard E. Thomas served as initial project officer and provided
stimulating discussions on land treatment of wastes. Mr. Lowell E. Leach
served in this capacity in the latter period and provided helpful suggestions
during the completion phase of the project.
xx
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SECTION 1
INTRODUCTION
Land application systems for treatment of wastes have been in operation
for a long time at a large number of locations. Several different techniques
(irrigation, recharge and overland flow) have been employed with a large
variety of wastes (agricultural, municipal and industrial). A review of many
of the land application systems (both U.S. and foreign) has been given by
Stevens (1972). Detailed reviews of facilities have been given also by
Sullivan et al_. (1973), Hartman (1975) and Carroll ejt al_. (1975). Two munici-
pal systems which have received particular attention include Melbourne,
Australia (Seabrook, 1975 and Johnson e_t a]_., 1974) and Pennsylvania State
University (Kardos e_t al_., 1974 and Richenderfer et aj_., 1975). In recent
years, a number of books have appeared on land treatment processes and systems
(Sopper and Kardos, 1973; Vesilind, 1975; Sanks and Asano, 1976; Shuval, 1976;
D'ltri, 1977; Elliot and Stevenson, 1977; and Loehr, 1977). Survey of the
literature has been given by Tofflemire (1977) and by Carlisle and Stewart
(1977).
Several other publications have appeared which aid in evaluation and
design of land treatment systems. The U.S. Environmental Protection Agency
has published a design manual (USEPA, 1977) which outlines factors to consider
and procedures for design and evaluation. Economic considerations have been
discussed by Young and Carlson (1974), Pound et_ al_. (1975) and Young (1976).
The city of Tallahassee was probably the first city in Florida to utilize
wastewater irrigation. During the 1940's, two treatment plants were con-
structed and subsequently discharged to a natural drainage stream and then
flowed to Lake Munson. Much of the surface drainaqe also flowed through this
stream and lake. In 1961, a 227 m3/day (0.060 mgd) high rate trickling filter
was constructed at the municipal airport. Field tests at that site showed
that the soil could sustain an irrigation rate of 100 mm/day (4 in./day)
satisfactorily. In 1966, a 9300 m-Vday (2.5 mgd) high rate trickling filter
was put into operation near the airport site, and included an irrigation
system with design capacity of 3700 m3/day (1 mgd). The irrigation field of
6.5 ha (16 acres) was divided into four equal plots. Experience showed that
these plots could handle 250 mm/day (10 in./day) over a four day rotation
without noticeable hydraulic problems. Plots received maintenance mowing
without removal of vegetation. The effects on groundwater quality were
unclear.
An extensive study of geological and groundwater characteristics was
conducted in the vicinity of the irrigation site and surrounding area during
the period March 1972-June 1974 by the U.S. Geological Survey (Slack, 1975).
-------
Logs were made on 23 test wells, along with hydrologic and chemical measure-
ments.
This study was initiated in 1971 to evaluate the effects of wastewater
irrigation of a sandy soil on 1) growth and yields of forage crops, 2) changes
in soil and groundwater characteristics and 3) coupling among transport
processes in the soil. Both summer and winter crops were grown which were
suitable for production in the southeastern United States and for which
extensive literature was available. Extensive literature was also available
on the soil type (Lakeland fine sand) prevalent at the treatment plant.
For convenience, a table of conversion factors from metric to English
units has been included (Table 1).
TABLE 1. CONVERSIONS FROM METRIC TO ENGLISH UNITS
Metric Unit
Factor
English Unit
meters (m)
millimeters (mm)
hectare (ha)
kilogram (kg)
kilogram/hectare (kg/ha)
metric ton/hectare (mton/ha)
hectoliter/hectare (hl/ha)
meter3/minute (m3/min)
meters/day (prr/day)
3.28
0.0394
2.
2,
,47
.205
0.892
0.446
0.87
263
263 • 10
-6
feet (ft)
inch (in)
acre (a)
pound (Ib)
pound/acre (Ib/a)
ton/acre (ton/a)
bushels/acre (bu/a)
gallons/minute (gpm)
million gallons/day (mgd)
-------
SECTION 2
CONCLUSIONS
This study demonstrated the feasibility of growing both summer and
winter forage crops under effluent irrigation.
Yields and nutrient contents compared favorably with values from the
literature.
Yields and nutrient uptake increased with application rate, while
efficiency of nutrient recovery showed a decrease. Nitrogen recovery above
50% required application rates of 25 to 50 mm/week (1 to 2 in./week).
Soil pH remained around 6.5, in the optimum range for crop production.
Lakeland fine sand was very effective in removing phosphate, BOD and
fecal coliform bacteria from the effluent.
Shallow groundwater was influenced by effluent irrigation, but mixing
with groundwater caused dilution.
Field measurements showed that nitrification essentially reached comple-
tion in the upper 120 cm (4 ft) of soil.
The model of phosphorus transport showed coupling between surface
exchange and convection. Surface exchange was diffusion limited at the
lower flow rates. Field and laboratory results correlated very closely.
A model of phosphate kinetics based on Langmuir-Hinshelwood kinetics
described batch data very well. Effects of soil/solution ratio and pH were
accounted for in this study. The model included both heterogeneous catalysis
and a homogeneous reaction.
The model of cation transport described data for NH^/K* system very
well. Surface exchange was shown to be diffusion limited.
-------
SECTION 3
RECOMMENDATIONS
The feasibility of a grazing operation coupled with effluent irrigation
should be investigated. This work showed that forage production was reason-
able for green chop.
Performance on poorly drained soil should be studied, with particular
reference to nitrogen behavior. In this work appreciable nitrogen did reach
the groundwater.
The relationship between cation exchange capacity and nitrogen uptake
should be established.
Role of various factors on retention and movement of pathogens in soils
receiving wastewater should be established.
Determine breakdown and movement of carbon compounds in soil receiving
wastewater.
A more accurate measure of long-term phosphorus fixing capacity of soils
is needed.
A simplified model of cation transport in a mixed cation system should
be developed.
-------
SECTION 4
SITE DESCRIPTION
LOCATION
The study was a cooperative effort between the city of Tallahassee,
Fieri da and the Agricultural Engineering Department, University of Florida,
Gainesville. All field studies were conducted in Tallahassee at the Thomas
P. Smith Wastewater Renovation Plant (formerly Southwest Sewage Treatment
Plant), located southwest of the city (Fig. 1) at the intersection of Spring
Hill Road and Capitol Circle (Fig. 2).
TREATMENT PLANT
In 1966, the high-rate trickling filter was put on line with a flow of
950 m3/day (0.25 mgd). By 1969 the flow had reached 3800 m3/day (1 mgd).
By October 1974 the Southwest Plant passed design capacity and reached 13000
m3/day (3.5 mgd), at which time the new 28,000 m3/day (7.5 mgd) conventional
activated sludge plant was opened. The name of the plant was then officially
changed to Thomas P. Smith Wastewater Renovation Plant. To accommodate the
steadily increasing flow, four large sprinklers were installed in a 7.3 ha
(18 acre) forest area to handle the flow above that needed for the agronomic
study. This unit went into operation in March 1972.
IRRIGATION SYSTEM
System layout was according to Figure 3. A centrifugal pump with 2.7
m /min (720 gpm) capacity provided effluent from the polishing pond. Irriga-
tion lines were portable aluminum with a 20-cm (8-in.) main, 10-cm (4-in.)
laterals and 5-cm (2-in.) sublaterals. Risers were 2.5-cm (1-in.) galvanized
pipe 3 m (10 ft) in height. The impact sprinklers were Rainbird 70 with a
delivery rate of 0.21 m^/min (55 gpm) at 850 kg/cm^ (60 psi), which provided
an application rate of 1.25 cm/hr (0.5 in./hr). Plots were 30 m x 30 m (100
ft x 100 ft) with 40 m (120 ft) between plots to reduce spray drift. Valves
were located on sublaterals to allow diverting of flow among the various
plots.
CHARACTERISTICS
The treatment plant was located adjacent to the Apalachicola National
Forest. Hendry and Sproul (1966) identified this area as part of the Lake
Munson Hills, at the western edge of the Woodville Karst Plain. Surface ele-
vation ranged 16-23 m (50-70 ft) above mean sea level, water table elevation
-------
TALLAHASSEE
Airport
Capitol Circle
Spring Hill Rd
Thomas P Smith
Waste water Renovation
Plant
Figure 1. General location of study site.
-------
Thomas R Smith
Wastewater Renovation
Figure 2. Detailed location of study site,
-------
0
o c
-------
ranged from 7-10 m (22-30 ft). The top of the Floridan aquifer was 0-4 m (Slack,
1975). A well, drilled at the site by the Florida Department of Natural Resources
Bureau of Geology for calibration of equipment, provided a stratigraphic
profile of the geology (Table 2). Core samples from the background well
(Table 3) showed sand underlain by clay at 11.5-17 m with limestone below
17 m. The water table depth was 13.5 m (45 ft) below ground surface. The
water table depth at the field well was 13 m (42 ft) below ground surface.
Soil samples collected prior to construction of the trickling filter showed
a pattern of 6-8 m (20-25 ft) of yellow quartz sand, a clay lens up to 3 m
(10 ft) in thickness, white quartz sand 3-4 m (10-12 ft) thick, then lime-
rock. Vegetation in the area was mostly turkey oak and slash pine. The soil
was Lakeland fine sand, a Quartzipsamment in the Entisol order. A soil
profile taken near the treatment plant showed the soil contained approximately
95% sand, 2% silt and 3% clay (Table 4). The pH of a 1:1 soil/water mixture
was approximately 5.5, and cation exchange capacity was very low. Water
holding capacity of the soil was about 8 cm/m (1 in./ft).
-------
TABLE 2. LITHQLOGIC LOG OF CALIBRATION WELL AT THE TREATMENT PLANT
Depth
Description
m
0-3 SAND, quartz, dark yellowish orange, fine to coarse, subangular-
subrounded, loose, trace - 1% heavy minerals.
3-4 SAND, as above, but very pale orange in color.
4-9 SAND, quartz, grayish orange to dark yellowish orange, fine to
coarse, mostly medium to coarse, loose, has burrowed or dis-
rupted liminae appearance.
9-10 SAND, quartz, very pale orange, fine to medium, some coarse,
loose, trace - 1% heavy minerals.
10-14 CLAY, mottled gray, light brown and dark yellowish orange, very
sandy and silty at top - decreasing downward, soft but tough,
waxy, abrupt contact with below.
14-15 CAVITY
15-17 CALCILUTITE, very pale orange, partially recrystallized, very
finely sandy, soft but tough, microfossiliferous (Sorites,
Miliolids).
17-18 CAVITY
18-18.5 CALCILUTITE, grayish orange, partially recrystallized, hard,
sandy.
18.5-19 CAVITY
19-20 CALCILUTITE, yellowish gray, very clayey textured and soft,
sandy.
20-23 DOLOMITIZED CALCARENITE, pale orange, very hard, partially
recrystallized, very microfossiliferous but indistinct.
23-26.5 CALCARENITE, pale yellowish orange, partially recrystallized,
hard to soft, very microfossiliferous with good porosity and
permeability in soft zones.
26.5-28 CAVITY - filled with rotten, broken limestone material.
(continued)
1,0
-------
TABLE 2. (continued)
DePth Description
28-39 CALCILUTITIC CALCARENITE, very pale orange, partially recrys-
tallize-d, very microfossiliferous, soft, good porosity and
permeability.
39-40 CALCILUTITE, very pale orange, partially recrystallized, hard,
very "tight" - silty textured.
40-46.5 CALCARENITE, very pale orange, partially recrystallized, very
microfossiliferous (first appearance of Leps) moderately hard,
very porous and permeable, appears to have calcareous algae
"globs" - especially from 140-148 feet, macrofossiliferous
molds.
46.5-51.5 CALCILUTITE, pale yellowish brown, partially recrystallized,
very evenly fine grained, microfossiliferous (no Leps),
friable, partially dolomitized. One inch base of interval
appears to be organic.
51.5-59.5 DOLOMITE, moderate yellowish brown, recrystallized, hard, some
moldic porosity, (with some zones silty textured and soft).
59.5-60 CAVITY
60-62 DOLOMITIC CALCARENITE, pale yellowish brown, very moldic, very
microfosslliferous but fossils indistinct, hard, brittle,
recrystallized, grades into below.
62-64.5 CALCILUTIC CALCARENITE, grayish orange, partially recrystal-
lized, microcoquina of small microfossils, porous and perme-
able, friable.
64.5-70 AS ABOVE, with few macrofossils fragments and molds and few
zones of complete recrystallization - lower three feet pale
yellowish brown in color.
70-71.5 CALCILUTITIC CALCARENITE, very pale orange, partially recrys-
tallized, microfossiliferous, soft to medium hard, with
harder gray zones (conglomeratic appearance).
71.5-73 AS ABOVE, but more recrystallized and harder - lower six
inches appears dolomitized (small silt size rhombs) and
laminated, and is pale brown (? organics) in color.
. _ , _ _ ^
(continued)
11
-------
TABLE 2. (continued)
DePth Description
m
73-73.5 DOLOMITE, pale brown, crystalline, very hard, microfossilif-
erous, but very indistinct, grades into below.
73.5-74 SAME AS 73-73.5.
74-74.5 SAME AS 73-73.5.
74.5-75 CAVITY.
75-76 DOLOMITE, light brown, crystalline (sucrosic), with zones of
non-crystalline, partially recrystallized Calcarenite, hard.
76-84 DOLOMITE, as 73-73.5, with some zones very micromoldic, grades
into below.
84-89 CALCARENITE, very pale orange, soft to moderately hard,
partially recrystallized, microfossiliferous, but indistinct,
intergranular and micromoldic porosity.
89- CALCARENITE, Pale yellowish brown, partially recrystallized,
very microfossiliferous but indistinct (many Leps), hard,
intergranular and micromoldic porosity but poorly permeable.
Source: Florida Department of Natural Resources, Bureau of Geology.
12
-------
TABLE 3. LITHOLOGIC LOG OF BACKGROUND WELL
Depth n ...
Description
0-0.3 Topsoil
0.3-1.5 Sand, dark yellow, medium grain size
1.5-3 Sand, light yellow, medium grain size
3-6 Sand, yellow, medium grain size
6-7.5 Sand, light yellow, trace of clay
7.5-9.5 Sand, very light yellow, medium grain
9.5-10 Sand, dark purple clay
10-10.5 Sand, gray, medium grain
10.5-11.5 Sand, white clay layers
11.5-13.5 Clay, gray, dense
13.5-15 Clay, dark yellow
15-16 Clay, deep yellow, greenish gray streaks
16-17 Clay, lime rock fragments
17-18 Limestone, soft white
18-21 Limestone, dolomite, yellowish brown
21-24 Limestone, dolomite, tan
Source: Florida Department of Natural Resources,
Bureau of Geology.
13
-------
TABLE 4. CHARACTERISTICS OF LAKELAND SAND NEAR THE IRRIGATION SITE
Particle Si
Depth
cm
0-8
8-58
58-104
104-155
155-185
185-203
Horizon
Al
Cl
C2
C3
C4
C5
pH
H20
5.5
5.7
5.4
5.5
5.3
5.0
CEC
meq/100 gm
3.59
1.39
1.37
1.11
0.83
0.54
VC
0.7
1.0
1,2
1.5
1.4
1.5
C
21.2
21.6
21.6
20.3
21.1
22.4
Sand
M
48.7
48.7
47.2
43.5
44.1
46.0
F
21.9
22.5
23.8
28.9
26.7
26.2
ze Distribution
VF
1.7
1.5
1.7
2.3
2.0
1.8
Total
94.2
95.3
95.5
96.5
95.3
97.9
Silt
2.6
1.9
1.0
1.5
1.1
0.7
Clay
3.2
2.8
3.5
2.0
3.6
1,4
CEC = cation exchange capacity
VC = very coarse, 2-1 mm
C = coarse, 1-0.5 mm
M = medium, 0.5-0.25 mm
F = fine, 0.25-0.10 mm
VF = very fine, 0.10-0.05 mm
Silt = 0.05-0.002 mm
Clay = < 0.002 mm
Source: University of Florida Soil Characterization Laboratory.
-------
SECTION 5
SYSTEM CHARACTERISTICS
INTRODUCTION
Data was collected on wastewater, groundwater and soil to characterize
response of the system to wastewater irrigation. Behavior of these three was
clearly interrelated. Groundwater samples were collected for the highest
irrigation rates due to failure of the wells at the lower rates. Climatic
data was included to show variability in temperature and rainfall. There were
several nights during the winter season when irrigation would have caused ice
formation. However, this was only a minor problem.
WASTEWATER
In September 1974 the activated sludge unit went on line. Values for BOD
and solids content (Table 5) for the period 4/71-9/74 were for the trickling
filter and for 10/74-3/76 were for the activated sludge plant. Final BOD was
TABLE 5. BOD AND SOLIDS CONTENT OF THE WASTEWATER*
BOD Total Solids Suspended Solids
Period Raw Final Raw Final Raw Final
mg/1 mg/1 mg/1
4/71-9/71
10/71-3/72
4/72-9/72
10/72-3/73
4/73-9/73
10/73-3/74
4/74-9/74
10/74-3/75
4/75-9/75
10/75-3/76
169
189
180
230
125
168
187
206
156
160
60
70
70
75
49
61
51
25
25
13
507
520
506
515
439
580
538
478
511
510
375
385
386
402
303
370
338
373
377
375
138
128
131
144
172
206
253
208
188
195
28
29
34
26
39
42
39
52
42
26
Avg. 177 50 610 368 176 36
* From a 24-hour proportional composite sample collected each week.
15
-------
measured in samples from the outfall of the polishing pond. Suspended solids
averaged 36 mg/1, which represented 4 mtons/ha/yr (2 tons/acre/yr) at 200 mm/
week. Even this high rate did not cause noticeable clogging of the soil.
Chemical characteristics were measured on 24 hr proportional composite samples
collected at the pump intake (Table 6). Average values obtained here agree
with those reported elsewhere (Kardos >e_t al_., 1974 and Metcalf and Eddy, Inc.,
1972).
GROUNDWATER
Background quality of groundwater in the vicinity of the treatment plant
was measured in a well near the power line (Figure 2). Concentrations of
various chemical elements were very low (Table 7) and remained essentially
constant during the study period. Chloride was approximately 2 mg/1, compared
to 50 mg/1 in the wastewater, and provided a good indicator for changes in
groundwater quality due to irrigation.
The field well (Figure 3) showed the influence of irrigation (Table 8).
Application rates for that plot were 200 mm/week (8 in./week) during the
summer season and 100 mm/week (4 in./week) during the winter season. Chloride
averaged 49 mg/1, compared to 51 mg/1 in the effluent. A mass balance for chloride
showed the effluent comprised about 96% of the groundwater at this well.
Total nitrogen averaged 18.6 mg/1, or 59% as much as in the effluent. It
should be noted that nitrification (NH4 •* NOj) was essentially complete.
Potassium concentration dropped from 6.2 mg/1 in the effluent to 0.7 mg/1 in the
well. The decrease in nitrogen and potassium was attributable, in part, to crop
uptake by the various crops grown on this plot. Total phosphorus decreased
from 10.5 mg/1 in the effluent to 0.021 mg/1 in the groundwater; soil fixation of
phosphorus was complete.
There appeared to be greater dilution of the percolating water with
groundwater in the well in the coastal bermuda (CB) plot (Table 9). Chloride
in the well was 38 mg/1, or 75% of the value for effluent. Based upon this
dilution factor, the concentration of total nitrogen in the percolating water
was 11.3/0.75 = 15 mg/1. Since the effluent averaged 31.3 mg/1, this
represented a change of about 16 mg/1, or roughly 50%. Since nitrogen
recovery by coastal bermudagrass at 200 mm/week (8 in./week) was less than
50%, some nitrogen appeared to be removed by other mechanisms. From this
study it was not possible to discriminate among accumulation by roots, assim-
ilation by organisms, or reduction by organisms. Average data for effluent
and the three wells were assembled for comparison (Table 10). For all param-
eters the field and CB well values were intermediate to effluent and back-
ground levels. Dilution was indicated by a comparison of the data with data
from the USGS study (Slack, 1975). Well 21, in the USGS study, was very near
the CB well and was cased to 75.3 m (247 ft). During 1974, chloride averaged
16 mg/1 and total nitrogen 3.3 mq/1.
Counts of fecal coliform, by the membrane method, never showed positive
counts, although the effluent was shown to contain as high as 10° fecal
coliform/100 ml. BOD measurements showed values below 5 mg/1. These results
indicated that the soil was very effective in removing bacteria and suspended
16
-------
TABLE 6. CHEMICAL CHARACTERISTICS OF THE SECONDARY EFFLUENT
Characteristic
Peri od
1 C 1 1 WJ
4/71-9/71
10/71-3/72
4/72-9/72
10/72-3/73
4/73-9/73
10/73-3/74
4/74-9/74
10/74-3/75
4/75-9/75
10/75-3/76
4/76-9/76
pH
7.6
7.2
7.2
7.3
7.2
7.4
7.3
7.6
7.6
7.7
7.8
G
umho
460
520
530
530
410
480
480
440
400
420
440
Cl
61
60
74
51
47
40
42
43
44
44
N03
N
3.2
4.4
2.8
2.6
2.6
2.0
2.8
7.9
4.7
8.7
12.9
NH4 Kjeldahl
N
18.2
19.3
19.5
20.1
13.7
18.2
17.2
11.3
11.5
7.4
2.0
N
21.4
_
33.0
36.7
23.9
28.4
33.2
31.8
25.7
17.0
10.1
Total
N
24.6
_
35.8
39.3
26.5
30.4
36.0
40.8
30.5
25.7
23.0
Ortho
P
mg/1
6.5
7.1
_
8.5
7.1
9.0
9.0
7.7
7.7
8.2
8.4
Total
P
_
12.6
13,3
9.4
11.2
11.0
8.8
9.1
9.5
9.4
K
_
6.1
-
7.5
5.5
3.7
4.0
5.8
8.8
8.4
Ca
-
32
-
64
32
29
29
28
36
34
Mg
-
9.6
-
17.6
9.3
8.7
10.0
9.4
10.3
9.6
Na
_
-
39
-
55
36
33
26
33
41
42
Avg. 7.5 465 51 5.0 14.4 26.1 31.3 7.9 10.5 6.2 35 10.6 38
-------
TABLE 7. CHEMICAL CHARACTERISTICS OF THE BACKGROUND WELL*
OD
Period
3/73-9/73
10/73-3/74
4/74-9/74
10/74-3/75
4/75-9/75
10/75-3/76
4/76-9/76
Avg.
pH
7.8
8.1
8.3
8.4
8.3
8.5
8.4
8.3
G
umho
58
48
46
47
51
57
61
53
Characteristic
N03 NH4 Kjeldahl Total Ortho
Cl N N N N P
2 <
2 <
2 <
2 <
1 <
1 <
1 <
2 <
1 <1 1.0
1 <1 1.0
1 <1 1.2
1 <1 1.0
1 0.1 0.9
1 0.1 1.0
1 0.1 0.8
1 <1 1.0
<2
<2
<2
<2
<2
<2
<2
<2
mg/1
0.014
0.014
0.011
0.004
0.007
0.009
0.010
Total
P
0.030
0.025
0.037
0.022
0.011
0.015
0.025
0.024
K
0.3
0.2
0.1
0.1
0.4
0.2
0.3
0.2
Ca
10.5
6.2
7.6
8.4
8.6
8.5
10.5
8.6
Mg
0.5
0.5
0.6
1,0
1.5
1.2
0.6
0.8
Na
1.4
0.7
0,8
1.1
3.8
4.7
1.0
1.9
From weekly samples.
TABLE 8. CHEMICAL CHARACTERISTICS OF THE FIELD WELL*
Period
4/73-9/73
10/73-3/74
4/74-9/74
10/74-3/75
4/75-9/75
10/75-3/76
4/76-9/76
Avg.
pH
7.5
7.5
7.7
7.9
7.7
7.9
7.8
7.7
G
umho
320
330
350
340
320
310
350
331
Cl
51
52
49
48
48
48
45
49
NO-, NH
N° N
16.4 <1
17.6
-------
TABLE 9. CHEMICAL CHARACTERISTICS OF THE COASTAL BERMUDA WELL*
Characteristic
Period
10/74-3/75
4/75-9/75
10/75-3/76
4/76-9/76
Avg.
PH
8.1
8.1
8.1
8.2
8.1
G
umho
310
320
300
340
320
Cl
36
43
38
37
38
NO.
IT
9.8
11.9
9.2
8.7
9.9
NH4
N
1.6
0.3
0.5
0.4
0.7
Kjeldahl
N
1.8
1.1
1.4
1.2
1.4
Total
N
11.6
13.0
10.6
9.9
11.3
Ortho
P
mg/1
0.016
0.011
0.009
0.008
0.011
Total
P
0.030
0.025
0.017
0.020
0.023
K
0.7
1.0
0.5
0.7
0.7
Ca
40
33
36
43
38
Mg
6.8
5.2
5.4
6.5
6.0
Na
17
24
21
24
22
* From weekly samples.
TABLE 10. AVERAGE CHEMICAL CHARACTERISTICS OF EFFLUENT AND VARIOUS WELLS
Characteristic
Sample
Effluent
Background
Well
Field Well
CB Well
PH
7.5
8.3
7.7
8.1
G
umho
465
53
331
320
Cl
51
2
49
38
NOo
n
5.0
<1
17.3
9.9
NH4
N
14.4
< 1
<1
0.7
Kjeldahl
N
26.1
1.0
1.3
1.4
Total
N
31.3
<2.0
18.6
11.3
Ortho
P
mg/1
7.9
0.010
0.010
0.011
Total
P
10.5
0.024
0.021
0.023
K
6.2
0.2
0.7
0.7
Ca
35
9
35
38
Mg
10.6
0.8
4.1
6.0
Na
38
2
27
22
-------
organics. Wells were always pumped a minimum of 2 min. before sample col-
lection to obtain a representative sample.
SOIL
Soil samples were collected from several plots at various depths and at
different times to characterize some of the soil properties in relation to
chemical processes and crop production. Since irrigation practices on the
plots were changed over the years from the beginning of plant operation in
1966, it was not possible to select plots which had received uniform treat-
ment. Results are reported for the plots on which coastal bermudagrass was
sprigged in 1973. The basic features of the system will be apparent from
the results.
Analyses were performed at the University of Florida Soil Testing Labora-
tory. After air drying, samples were passed through a coarse sieve to remove
roots and other debris. Soil pH was measured in a slurry of 50 g soil/100 ml
distilled water using a minimum equilibration period of 30 minutes. Analyses
of pH, phosphorus and extractable bases (K, Ca, Mg, Na) were performed using
5 g soil in 25 ml extractant of 0.7 N ammonium acetate in 0.54N acetic acid
buffered at pH 4.8. A shaking time of 30 minutes was used.
In 1971 and 1972 soil samples were collected at depth increments of 0-15
cm and 15-30 cm with an auger. The need for more detail became apparent. In
1973 samples were collected at depths of 15, 30, 60, 90 and 120 cm. Soil was
removed with hole diggers to within 4 cm of the selected depth. A sample
8 cm in length was then collected with a 5-crn diameter tube.
High-rate irrigation experiments were conducted to measure distributions
of phosphate, ammonia and nitrate in the soil solution. Attempts to collect
soil solution samples at irrigation rates up to 200 mm/week failed due to the
hydraulic characteristics of the sandy soil. Samples were collected under
continuous irrigation.
Results are given in Tables 11-13 and Figure 4. These values were in
the same range as the value 6.4 reported by Fiskell and Zelazny (1971) for
Lakeland soil. Values of pH changed little or none with depth. Hortenstine
(1973) observed this same effect with effluent irrigation on Immokalee sand
at Walt Disney World in Florida.
Extractable Bases
By leaching soil with a neutral salt, such as ammonium acetate, it is
possible to determine the extractable (or exchangeable) basic cations (pri-
marily K, Ca, Mg, Na) held by the soil (cf, Jacobs ejt aj_. , 1971).
Results for this study are shown in Tables 11-14 and Figures 5-11. A
noticeable change in the balances of cations occurred between the sampling
dates of 3/71, 10/71 and 3/72 (Tables 11-13); viz an increase in calcium
20
-------
TABLE 11. CHARACTERISTIC OF SOIL EXTRACTS - MARCH 1971.
Plot
1
2
3
4
Avg.
Depth
cm
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
PH
6.5
6.5
6.5
6.6
6.6
6.7
6.7
6.7
6.6
6.6
P
mg/kg
15.
7.
15.
8.
18.
10.
28.
19.
19.
11.
5
6
7
7
0
6
7
0
5
5
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
K
038
031
066
036
064
046
069
046
059
041
1
0
0
0
1
0
1
0
1
0
Ca
meq/100
.15
.55
.95
.53
.06
.65
.16
.75
.08
.62
Mg
0.56
0.43
0.55
0.47
0.56
0.45
0.61
0.51
0.57
0.47
0
0
0
0
0
0
0
0
0
0
Na
.69
.61
.60
.59
.60
.62
.60
.62
.63
.61
TABLE 12.
CHARACTERISTICS OF
SOIL
EXTRACTS
- OCTOBER
1971.
Plot
1
2
3
4
Avg.
Depth
cm
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
PH
6.5
6.5
6.8
6.8
6.5
6.7
6.6
6.6
6.6
6.6
P
mg/kg
17.
15.
19.
11.
16.
14.
16.
11.
17.
13.
1
3
2
7
7
1
8
3
4
1
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
K
038
020
054
041
028
020
049
026
041
026
2
1
1
0
1
0
1
0
1
1
Ca
meq/100
.12
.35
.58
.85
.52
.90
.48
.92
.68
.01
Mg
gin - -
0.41
0.36
0.44
0.26
0.30
0.24
0.42
0.26
0.39
0.28
_ _
0
0
0
0
0
0
0
0
0
0
Na
.41
.37
.39
.37
.39
.39
.39
.39
.40
.38
21
-------
TABLE 13. CHARACTERISTICS OF SOIL EXTRACTS - MARCH 1972.
Plot
1
2
3
4
Avg.
Depth
cm
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
p
P mg/kg
6.9 17.1
6.9 18.1
6.9 16.4
6.9 16.3
6.9 15.3
7.0 17.8
6.9 22.8
6.9 19.8
6.9 17.9
6.9 18.0
K Ca Mg
0.013 1.70 0.38
0.015 1.62 0.39
0.038 1.55 0.31
0.031 1.50 0.36
0.010 1.38 0.36
0.010 1.45 0.34
0.015 1.80 0.39
0.008 1.30 0.34
0.020 1.60 0.36
0.015 1.47 0.35
Na
0.39
0.35
0.37
0.35
0.35
0.37
0.39
0.39
0.37
0.36
TABLE 14. EXTRACTABLE BASES
Plot
1
2
3
4
Avg.
Depth
cm
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
0-15
15-30
4/71
2.44
1.62
2.17
1.62
2.29
1.76
2.44
1.92
2.33
1.73
10/71 4/72
- - - lllcLj/ 1 UU y!ll bU ! 1 - - -
2.99 2.48
2.10 2.37
2.46 2.27
1.52 2.24
2.25 2.09
1.55 2.17
2.33 2.60
1.60 2.04
2.51 2.36
1.69 2.21
Avg.
2.63
2.03
2.30
1.79
2.21
1.83
2.46
1.85
2.40
1.88
22
-------
PLOT
I
I—
O.
O
fill f I I
(!) 1
D 2
4—4- till!
Figure 4, Distribution of pH 1n field plots,
23
-------
0
1 I —I I I I
Figure 5. Distribution of K in field plots,
24
-------
en'
o
fi.
I—
CL
Q
, MEO/100 GM
f i Y i
PLOT
\ \ I I \ \ I
Figure 6, Dtstrtbutlon of Na 1n field plots,
25
-------
Cfi, MEO/100 GM
o
tf>"~
«LJ
»
I
I—
CL
g.
O*
o
Al-
O
un-
4—1 -\ f
4—+
Figure 7. Distributton of Ca tn field plots,
26
-------
. MEQ/1QO GH
Figure 8, Distribution of Mg in field plots.
27
-------
EXTRflCTHBLE BflSES, HEO/100 GM
o. „
"""
CJ
fr
I—
Q_
Q
P. .
o
PLOT
O 1
D 2
A 3
Figure 9, Distribution of total extractable bases
1n field plots.
28
-------
> [
<*>
ELEHEMT
O K
Nfi
D
MG
o
Figure 10. Distribution of extractable bases
in field plots.
29
-------
FRfiCTION, %
CJ
10-
75
00
Figure 11. Distribution of base exchange fraction
in field plots.
30
-------
with a corresponding decrease in the others. The quantity of extractable
bases remained essentially constant with time (Table 14), but showed a
decrease from 2.40 at 0-15 cm to 1.88 at 15-30 cm.
In 1973, soil samples were collected from five depths. Potassium and
sodium showed little change with depth (Figures 5 and 6), while calcium and
magnesium showed strong decreases with depth (Figures 7 and 8). These values
are in the same range reported by Fiskell and Zelazny (1971) for Lakeland
soil. The sum of extractable bases.decreased with depth (Figure 9). The same
trend was reported by Fiskell and Zelazny (1971) for Lakeland and by Horten-
stine (1973) for Immokalee soil. Greater weathering and higher organic matter
near the soil surface cause this distribution. Values for the four plots were
averaged for each depth to obtain average base cation concentrations. Values
were then averaged for each cation from the four plots and divided by the
average base concentration to determine base exchange fraction. Results are
shown in Figure 10 for the four cations. More than one-half the base exchange
was occupied by calcium. Most soils are dominated by calcium (Jacobs et a1.,
1971; Buckman and Brady, 1969; Fiskell and Zelazny, 1971; and HortenstTne,
1973). Potassium occupied less than 5% of base exchange, due to the fact
that the fraction of potassium in the effluent was very low (less than 5%).
The calcium fraction decreased with depth, from 70% at 15 cm to 54% at
120 cm (Figure 11). Sodium showed a corresponding increase from 15% at 15 cm
to 30% at 120 cm. It can be shown that for a mixed cation system (monovalent
and divalent cations) that as total cation exchange capacity decreases the
balance of adsorbed cations will shift toward monovalents and away from diva-
lents. This agrees with the increase of sodium with depth and the compli-
mentary decrease of calcium, induced by the decrease of base exchange with
depth.
The distribution of basic cations between adsorbed and solution phases
are shown in Table 15 for the 15 cm depth. Overman and West (1972) showed
TABLE 15. DISTRIBUTION OF BASIC CATIONS BETWEEN
ADSORBED AND SOLUTION PHASES.
Cation K Ca Mg Na
Adsorbed,
Solution,
Adsorbed
meq/100 gm
meq/1
0
0
3R
.036
.16
1
1
176
.66
.60
0
0
71
.33
.79
0
1
36
.36
.70
that Lakeland fine sand drained to a water content of approximately 10% under
gravity drainage. Assuming a bulk density of 1.70 g/cm3, the distribution
ratio for potassium was calculated to be:
31
-------
K Adsorbed 0.036 meg (1.70)g cm3 103cm3 1 ,R
K Solution " 100 mg cm3 (Oj0)crr)3 1 (0.16)meq " JB
Solution values were assumed to be the.same as in the effluent. Even though
the exchange capacity of the soil was low, the reserve of adsorbed cations was
appreciable.
Phosphorus
Values for ammonium acetate - extractable phosphorus (Tables 11-13 and
Figure 12) showed a strong decrease with depth in all cases. This decrease
in weakly bound phosphorus with depth resulted from the logarithmic' decay in
solution P concentration with depth due to phosphorus fixation by the soil
(Overman ejt al_., 1976). A plot was irrigated with effluent continuously for
three days in July, 1970, and soil solution samples were collected at the end of
that period. Measurements of orthophosphate showed a decrease from approxi-
mately 10 mg/1 P in the effluent to 0.1 mg/1 P at 120 cm (Figure 13), for a
removal of 99%. Hortenstine (1973) observed this same decay on Immokalee
sand receiving effluent. Phosphorus fixation in these Florida acid soils was
associated with oxides of iron and aluminum. Hortenstine (1973) demonstrated
that addition of lime to the soil enhanced fixation. Hook e^t a]_. (1973)
reported rapid fixation of phosphorus by a clay loam soil in the Pennsylvania
State University studies. More than 90% of the phosphorus in the effluent was
removed in the upper 15 cm of soil.
Nitrogen
The soil solution samples collected for phosphate analysis from the
three-day continuous irrigation were also analyzed for NH*-N and NOq-N.
Ammonia concentration showed a rapid decrease with depth (Figure 14), and
appeared to follow first order kinetics. Nitrate concentration showed a
corresponding increase with depth. These measurements indicated a high level
of activity by nitrifying organisms in the soil, since nitrification was
essentially complete in the upper 90 cm.
CLIMATE
Temperature and rainfall data were taken from National Oceanic and
Atmospheric Administration records at the Tallahassee Municipal Airport
located approximately 3 km (2 mi.) from the treatment plant (Tables 15-20).
The transition from cool to warm season occurred during March-April, while
the reverse transition occurred during October. Accordingly, summer crops
were planted around April 1 and winter crops were planted in October. While
the average minimum temperature was above freezing for all months, the number
of days with freezing temperatures ranged from 21 in, the 1971-1972 winter sea-
son to 50 in the 1975-1976 winter season. Daytime temperatures were always
above freezing. June-September represented the period of high stress for
crop growth due to high daytime temperatures. Rainfall was extremely vari-
able during the period 1971-1976, with an average value of 179 cm (71 in.)
and a range of 148-223 cm (58-88 in.). The least monthly rainfall was 1.40
cm (0.55 in.) in April 1972, while the greatest monthly value was 44.52 cm
32
-------
P, MC/KC
1 i ! i 'f
Figure 12. Distribution of extractable P in
field plots.
33
-------
o
Figure 13. Distribution of solution P
under steady irrigation.
34
-------
o. „
^
CJ
O
Q= _
o
o
NHi
i I 8 g I S I
Figure 14, Distribution of NH4-N and N03-
under steady irrigation
35
-------
(17.5 in.) in July 1975. The greatest amount in a single day was 14.73 cm
(5.8 in.) in June 1975. Runoff was not a problem due to the high permeability
of the sandy soil. Frequent afternoon showers during June-August did present
some difficulty with harvests. In spite of rainfall and sizable irrigation
levels, summer crops did show moisture stress at times due to the low water-
holding capacity of the soil.
36
-------
TABLE 16. CLIMATOLOGICAL DATA FOR TALLAHASSEE - 1971*
Temperature, °C
Year
1971
Number
Month
Jan
Feb
Mar
Apr
May
June
July
Aug
Sept
Oct
Nov
Dec
of days
Max
27
27
28
31
33
37
35
34
34
34
30
29
Ava
Max
18
19
21
26
29
33
32
32
32
29
23
23
with freezing -
Avg
11
12
13
17
21
26
26
27
26
22
14
17
39
Avg
Min
3
4
4
8
13
19
21
21
20
15
6
11
Min
-12
-10
-5
-2
1
14
19
19
12
5
-3
-1
Rain
Total
7.72
13.92
12.23
4.70
10.36
18.90
27.43
27.31
3.99
8.79
2.24
10.44
, cm
Greatest
Day
3.38
5.72
3.33
1.85
3.78
5.26
8.53
4.39
1.73
5.84
1.19
4.65
* Source: National Atmospheric and Oceanic Administration.
TABLE 17. CLIMATOLOGICAL DATA FOR TALLAHASSEE - 1972*
Temperature, °C
Year
Month
Avg
Max Max
1972
Number
Jan
Feb
Mar
Apr
May
June
July
Auq
Sept
Oct
Nov
Dec
of days
28
27
29
33
32
37
36
38
36
32
30
27
with freezi
21
18
24
28
29
32
33
34
33
28
21
21
ng -
Avg
15
12
16
20
23
26
27
28
26
21
15
14
23
Avg
Min
9
6
7
12
17
19
21
22
19
14
9
7
Min
-4
-6
-1
3
8
9
16
19
16
6
-4
-3
Rain
Total
16.56
17.91
14.73
1 .40
23.06
28.27
10.49
13.28
0.28
4,45
25.04
12.32
, cm
Greatest
Day
3.73
4.57
6.63
0.66
10.01
14,73
3.35
4.04
0.15
2.95
10.59
7.75
* Source: National Atmospheric and Oceanic Administration.
37
-------
TABLE 18. CLIMATOLOGICAL DATA FOR TALLAHASSEE - 1973*
Temperature, °C
Year Month
1973 Jan
Feb
Mar
Aor
May
June
July
Aug
Sept
Oct
Nov
Dec
Number of days
Max
27
24
29
30
35
35
35
35
34
32
29
26
Avg
Max
18
18
24
25
29
32
34
33
32
29
25
19
with freezing -
Avg
11
11
18
18
22
27
28
27
27
21
18
11
32
Avg
Min
4
3
12
11
16
21
23
22
22
13
11
3
Min
-8
-8
0
1
4
19
20
17
18
-1
-1
-8
Rain
Total
12.60
18.19
34.47
33.35
21.29
18.01
11.20
27.38
13.46
5.97
8.15
18.95
, cm
Greatest
Day
3.07
7.65
8.74
11.86
7.62
4.22
2,21
4.37
4.29
3.12
4.95
4.62
* Source: National Atmospheric and Oceanic Administration.
TABLE 19. CLIMATOLOGICAL DATA FOR TALLAHASSEE- 1974*
Temperature, °C
Year
Month
Avq
Max Max
1974
Number
Jan
Feb
Mar
Apr
May
June
July
Aug
Sept
Oct
Nov
Dec
of days
27
26
31
29
34
34
35
34
34
30
29
27
with freezi
24
20
26
26
31
32
33
32
31
27
22
18
ng -
Avg
19
12
18
18
24
26
27
27
26
18
14
11
31
Avg
Min
14
4
11
11
17
19
21
22
21
10
6
4
Min
6
-8
2
1
8
14
16
21
12
5
-4
-7
Rain
Total
8.53
7.29
7.62
10.13
21.82
9.75
19.30
23.83
26.49
2.36
4.17
9.65
, cm
Greatest
Day
3.15
4.24
3.35
5.46
8.79
3.23
4.39
7.75
9.07
2.36
2.03
3.76
* Source: National Atmospheric and Oceanic Administration.
38
-------
TABLE 20. CLIMATOLOGICAL DATA FOR TALLAHASSEE - 1975*
Temperature, °C
Year
Month
Avg
Max Max
1975
Number
Jan
Feb
Mar
Apr
May
June
July
Aug
Sept
Oct
Nov
Dec
of days
27
27
28
33
36
34
34
36
34
31
29
26
with freezi
19
21
22
26
31
32
31
33
30
27
23
18
ng -
Avg
13
14
16
19
24
27
26
27
25
21
16
11
38
Avg
Min
6
7
9
11
18
21
22
22
19
15
8
3
Min
-4
-6
-1
0
14
17
17
21
10
4
-3
-6
Rain
Total
29.67
7.24
15.70
18.21
26.26
12.12
44.52
17.27
12.40
11.20
3.81
19.89
, cm
Greatest
Day
8.28
2.72
8.51
7.52
4.70
5.46
11.61
4.83
5.49
8.15
2.51
8.92
Source: National Atmospheric and Oceanic Administration.
TABLE 21. CLIMATOLOGICAL DATA FOR TALLAHASSEE - 1976*
Temperature, °C
Year Month
1976
Number of
Jan
Feb
Mar
Apr
May
June
July
Aug
Sept
Oct
Nov
Dec
days with
Max
24
28
29
33
31
36
38
36
34
31
25
25
freezi
Avq
Max
17
23
24
28
29
31
34
33
31
24
19
17
ng -
Avg
8
14
17
19
22
26
28
28
25
17
12
10
48
Avq
Min
1
5
10
11
16
20
22
22
19
11
5
3
Min
-9
-7
0
3
8
16
20
19
13
2
-6
-7
Rain
Total
14.05
3.07
13.46
4.19
29.62
27.99
10.64
18.67
7.09
29.95
26.52
10.39
, cm
Greatest
Day
6.71
2.01
5.38
1.70
7.67
6.65
3.10
5.72
3.45
9.27
12.53
2.34
*Source: National Atmospheric and Oceanic Administration.
39
-------
SECTION 6
CROP YIELDS AND GROWTH RESPONSE
INTRODUCTION
These studies focused on agronomic field crops; viz, forage and grain
crops. Crops grown are listed in Table 22. Corn was grown for both silage
and grain. All of these (except kenaf) are grown extensively in the United
States, so that considerable experience is already available on their produc-
tion and utilization. Also, data on growth and nutrient uotake is available
from the literature, providing comparison between response to fertilization
and response to effluent irrigation.
Limited studies were conducted on several species of trees to determine
the response to effluent irrigation on well-drained soil.
TABLE 22. CROPS GROWN UNDER EFFLUENT IRRIGATION
_ AT TALLAHASSEE, FLORIDA
Common Name _ Scientific Name _
Summer Crops
Coastal bermudagrass Cynodon dactylLon (L.)
Pearl millet Pe.nvuA£tim typhA
Staph and E. C. Hubbasid
Sorghum x sudangrass Sorghum vulgate P&IA. x
Corn Zea Mat/4 L.
Kenaf Ht/b-c6coi eannab.-cna6 L.
Winter Crops
Rye
Ryegrass LolMm
Effluent irrigation should be viewed in two ways: 1) wastewater renova-
tion and 2) crop production. Viewed by the first, the nutrients of concern
are nitrogen and phosphorus; by the second, major (N, P, K), minor (Ca, Mg,
etc.) and micro (Fe, Zn, Cu, etc.) elements are all important. For example,
40
-------
removal of nitrogen from the wastewater by the crop depends upon crop vigor,
which depends upon other elements (such as K). For this reason, wastewater
and plant samples were analyzed for a variety of elements other than N and P.
Application levels of an element were estimated from average effluent
concentration for the crop season, irrigation rate and irrigation period.
The formula used was
A = 0.01 CIT
where A = nutrient applied, kg/ha
C = concentration in effluent, mg/1
I = irrigation rate, mm/week
T = irrigation period, weeks
To aid in conversion between English and metric units, a table of conversion
factors (Table 1) has been included in this report. For example, 1 kg/ha =
0.892 Ib/acre; a value in Ib/acre is 0.892 times the value in kg/ha.
Crop uptake of an element was estimated by
H = 0.1 YDN
where H = nutrient harvested, kg/ha
Y = green yield, metric tons/ha
D = dry matter, %
N = nutrient composition, %
Crop recovery of an element was calculated from the definition of simple
recovery as
R = j x 100
where R is recovery efficiency in %. It should be noted that some investi-
gators correct H for background uptake where no nutrient is applied,
reflecting base fertility of the soil. For Lakeland fine sand base fertility
is low, so that simple recovery is adequate. The significance of recovery
efficiency should be properly understood -- it indicates that capacity of the
crop to capture the particular element under the prevailing environmental
conditions, and reflects crop/soil/environmental interactions. It does not
provide a mass balance for the element, since no indication of storage (roots,
soil, organisms), leaching to groundwater, or gaseous losses are provided.
Net values for dry matter content and nutrient content were calculated
as weighted averages by the formula
N
V = I V W /W
avg n n
n=l
41
-------
where Vavq = weighted average value, %
Vn = value for nth harvest, %
Wn = dry weight for nth harvest, mton/ha
W = total dry weight for all harvests, mton/ha
CROP YIELDS AND NUTRIENT RECOVERY
Results are presented in this section on crop production under waste-
water irrigation on Lakeland fine sand. Measurements were made of green
weight, dry matter composition and nutrient composition for the various field
crops. Estimates were then made of dry yields, nutrient uptake and recovery
efficiencies. The approach was to use several crops under various irrigation
rates to identify suitable crops and to bracket the loading rates. It is
important in fertility studies to have enough treatment levels (minimum of
three) to be able to estimate the response curve, either yield vs rate or
nutrient vs rate. Such curves approximate a curve of diminishing returns,
exhibiting an asymptotic approach to a maximum. Data presented here follows
that general trend.
Availability of equipment and personnel for the project favored treatment
levels over replication. All harvesting operations utilized an available
commercial forage harvester (rather than a plot harvester) with a work force
of no more than two persons. In most cases, four irrigation rates were used.
Irrigation sprinklers were located on 30 m x 30 m (100 ft x 100 ft) spacing.
Irrigation intensity was 13 mm/hr (0.50 in./hr).
Throughout the experiments no commercial fertilizer, herbicides or
pesticides were used. Limited cultivation of crops was practiced for weed
control. In some cases, weed infestation did present a problem.
In this section summaries of yield, nutrient uptake and nutrient recovery
are presented for the crops listed in Table 22. These response curves were
estimated for each crop from the basic data compiled in Appendix A, In
Appendix A data are presented by years due to commonality of effluent charac-
teristics and cultural practices. In this report mton is used to denote
metric tons, to minimize confusion. Cultural practices and analytical pro-
cedures are included in Appendix A, also.
Coastal Bermudagrass
Estimates of yields and nutrient uptake for coastal bermudagrass are
shown in Figures 15-23. All of the curves exhibit the asymptotic response
which is typical of fertility studies. Dry matter content averaged about 28%
in the green forage. Values for dry matter yield (Figure 15) agreed closely
with fertility studies by Burton ejt aj_. (1963). Estimates of N uptake
(Figure 16) also increased with application as reported by Burton et al.
(1963), showing close agreement at lower rates and slightly below their values
at higher application rates. It should be noted that application rates were
for the growing season (approximately 6 months) rather than for the year.
Recovery efficiency followed a curve of diminshing returns, dropping from 85%
42
-------
CE
X
O
yj
o
GC
cc
>_
cc
Figure 15. Estimated yield response of coastal bermudagrass,
-------
cr o
o
LU
*:
CT
H 1 1 h 1 h- 1 1 h
H h
f
^00 $00 1200 1600
N flPPLICflTION, KG/Hfl
o
•o
QZ
. .p >
UJ
-MC
2000
Figure 16. Estimated nitrogen recovery by coastal bermudagrass.
-------
X
o
g-
«
LU o
-I 1 1 1 1 1 1 1
UPTflKE
RECOVERY
-I 1 1 h- 1 h S
100 200 30© 100
P RPPLICfiTIGN, KG/Hfl
,o
00
•S
.o >
» O
o
soo
Figure 17. Estimated phosphorus recovery by coastal bermudagrass.
-------
-pi
cr>
O
SO " 120 " 180
K flPPLICflTION, KG/Hfl
300
Figure 18. Estimated potassium recovery by coastal bermudagrass.
-------
CC
o
O.
<£>
a:
i—
a.
CE
O
o
^ 1-
-i 1 1-
_o
RECOVERY
-h- 1 h 1 h 1 1 f-
300 SOO 900 S 200
Cfl flPPLICflTION, KC/Hfl
CC
LU
4.0 >
CJ
o
isoo
Figure 19. Estimated calcium recovery by coastal bermudagrass.
-------
OD
o, „
*~
O
o S--
^ 1 1—h—i—h-—i
RECOVERY
100 200 300 100
MG RPPLICflTION, KG/Hfl
.0
3"
CC
UJ
I o >
"M O
UJ
500
Figure 20, Estimated magnesium recovery by coastal bermudagrass.
-------
oc
^
o
cc
I—
cs_
H 1 ! 1 1-—I 1 \-
ECDVERY
+
or
UJ
UJ
-------
a:
x
o
•h
LU
en
O
4- 1 H-—|
1- S-
RIECOVERY
4 -f
+
+
+
4» 1-
+
5 JO 35 30
FE flPPLICflTIGN, KG/Hfl
o
•o
,ltf» «^»
ir*. &3
ec
UJ
J_o >
"*"iui o
O
yj
•f flC
-4C f
Figure 22. Estimated iron recovery by coastal berrnudagrass.
-------
8
T&m, „
o
UJ IP.
cc
0
4- h
UPTflKE
RECOVERY
+- 1
.o
o:
yj
>
o
4J
LLJ
OC
10
ZN RPPLICflTION, KG/Hfl
Figure 23. Estimated zinc recovery by coastgl bermudagrass.
-------
at 200 kg/ha to 60% at 400 kg/ha. The response curve of P (Figure 17) also
showed asymptotic response. These values agreed closely with those of Adams
ejt al_. (1967). Although P recovery by the crop was low, losses of P were
minimal since this soil had a high capacity to retain P (Overman, et al..
(1976). Results indicated that coastal bermudagrass showed strong response
to K (Figure 18). For application rates below 200 kg/ha, K uptake exceeded
application, suggesting possible need for supplemental K. Results from fer-
tility studies (Adams ejb al., 1967 and Woodhouse, 1968) agreed with these
estimates, and also showecTuptake in excess of application.
Uptake of other elements by coastal bermudagrass is shown in Figures 19-
23. These may aid in estimating the mineral and trace element composition
of the forage for animal feed.
Under conditions of adequate moisture and nutrients, coastal bermuda-
grass should be harvested 5 or 6 times during the warm season. From Figure
15, for an N application of 400 kg/ha (360 Ib/acre) the estimated yield of
dry forage was 10 mtons/ha (4.5 tons/acre). For hav production (65% dry
matter) this represented 15 mtons/ha (7.0 tons/acre), while greenchop (28%
dry matter) was 36 mtons/ha (16 tons/acre).
Sorghum x Sudangrass
A strong response to nutrient application occurred for sorghum x sudan-
grass (Figures 24-32). The yield curve (Figure 24) agreed fairly closely with
fertility studies in Gainesville, Florida, with this variety (Agronomy Mimeo
Report, 1971), where 228 kg/ha applied N produced 9.3 mton/ha of dry forage.
Nitrogen content (approximately 1.75%) agreed with the range of values from
experiments in Alabama (Hoveland et al., 1967), and were somewhat below the
2.5% from Reulke and Prine (1974) in Florida using more frequent harvest than
in the present study.
Uptake of K by sorghum x sudangrass (Figure 27) exceeded application
below 120 kg/ha. This indicated potential K deficiency with effluent irri-
gation and possible need for supplemental K. Other elements were supplied in
adequate quantities 'since recoveries were below 100% (Figures 28-32).
With adequate moisture and nutrients, sorghum x sudangrass should be
harvested about 3 times during the season. Estimated yields of dry forage
from Figure 24 were 10 mtons/ha (4.5 tons/acre) at 400 kg/ha (360 Ib/acre)
applied N. Corresponding yields of green chop (19% dry matter) were 53 mtons/
ha (23 tons'/acre).
Pearl Millet
Pearl Millet showed a strong response to applications of nutrients
(Figures 33-41). Estimated yields (Figure 33) agreed well with those from
Florida (Agronomy Mimeo Report, 1971) and from Georgia (Hart and Burton,
1965.) Nitrogen uptake rose rapidly with increases in applied N (Figure
34), while recovery dropped sharply from approximately 50% at 200 kg/ha of N.
These values of uptake by pearl millet were somewhat below those of Hart and
Burton (1965), primarily due to a harvest frequency of roughly 8 weeks in the
52
-------
^—i—i—i
Ol
CO
cc
i|00 800 1200
Ml flPPLICflTION, KG/Hfl
2000
Figure 24, Estimated yield response of sorghum x sudangrass.
-------
en
CE ©
o
cc
^_
Q-
-I fc
i S
-S h—+
HOO " 800 1200 -1600
N RPPLICfiTION, KG/Hfl
RECOVERY
4—+
,o
'CD
-t.° ^s
""*Bf'J,r.«^ **•*
CC
yj
,o >
is- 0
o
yj
2000
Figure 25, Estimated nitrogen recovery by sorghum x sudangrass.
-------
O
O-
en
cr
3:
o
*
UJ o.
4—rH 1 h 1 h 1 1
+—s-—lisa
ISO 300 5150 " 600
P RPPLICflTION, KG/Hfl
RECOVERY
g S
0=
J_G >
O
•f fiE
. a,
750
Figure 26, Estimated phosphorus recovery By sorghum x sudangrass.
-------
en
01
@D 120 ISO Z>10
K flPPLECflTIGN, KG/Hfi
Figure 27. Estimated potassium recovery by sorghum x sudangrass,
-------
en
(100 300 1200 1600
Cfl RPPLICflTION, KG/Hfl
aooo
Figure 28. Estimated calcium recovery by sorghum x sudangrass.
-------
o
en
co
f-—I 1—I-
.0
100 200 500 100
MG flPPLICflTION, KG/Hfl
500
Figure 29. Estimated magnesium recovery by sorghum x sudangrass.
-------
f- 1 h—4-
en
UD
o
is:
500 1000 1500
fiPPLICfiTION,
Figure 30, Estimated sodium recovery by sorghum x sudangrass,
-------
5 10 15 £0
FE RPPLICflTION, KG/Hfl
Figure 31. Estimated iron recovery by sorghum x sudangrass.
-------
en
i g i \
RECOVERY
8 sa i@
ZN flPPLICfiTION, KG/Hft
- -Brt K|
•o
Figure 32. Estimated zinc recovery by sorghum x sudangrass.
-------
2
O
o
CE
u.
CE
O
» I I I
4- 1 I I
1100 800 iaOO 1600
N fiPPLICRTION, KG/Hfl
2000
Figure 33. Estimated yield response of pearl millet.
-------
en
OJ
o
o
LU S.
i£ 01
CE
J—
o.
H h—H h 1-
-I h 1-
! I
4-
.0
"at
-8
a=
UJ
.0 >
3- CD
O
yj
• CC
_ .o
WG 800 1200
N fiPPLICRTION, KG/Hfl
2000
Figure 34. Estimated nitrogen recovery by pearl millet.
-------
CTi
-p.
o
o
a:
x JC
x
o
LU o. _
-I —h 1"
01
lU
.0 >
RECOVERY
^—i—i
100 200 300
P flPPLICflTIQN, KG/Hfl
500
Figure 35. Estimated phosphorus recovery by pearl millet.
-------
O1
en
10 90 120 " ISO
K flPPLICfiTION, KG/Hfl
200
Figure 36. Estimated potassium recovery by pearl millet.
-------
CTl
CTl
o
*
LU oj.
a:
i—
a.
•* ! f-
H f—+
H h
UPTflKE
_ .o ..
-^ffli s+i
ac
yj
.0 >
fw o
O
LsJ
RECOVERY
300 " 800 300 1200
Cfl RPPLICfiTIGN, KG/Hfl
ssoo
Figure 37. Estimated calcium recovery by pearl millet.
-------
cr>
o
o-
CE o
O
i
4—H h- h
o
•o
IfM
o
-in
ECOVERY
o >
•o
.2 o
o
_o
iin
•f
100 200 300 100
HG fiPPLICfiTION, KG/HR
•o
soo
Figure 38. Estimated magnesium recovery by pearl millet.
-------
00
CE
X
O
CE
I—
O.
H S h
I I
UPTflKE
cc
o
o
CE
RECOVERY
4-
4- 1-
iaoo
Nfl flPPLICflTION, KG/Hfl
aooo
Figure 39. Estimated sodium recovery by pearl millet.
-------
CTl
LD
X
o
a.
LU
I h 1
OVERY
B I I
* 10 IS
RPPLICflT
I I-
20
S ^?
flc
UJ
^g
O
laj
r ec
t yj
o
Figure 40, Estimated iron recovery fay pearl millet,
-------
o
cz
l__
a,
I i 8
ECDVERY
^ — s- — i
i
\ \
a '4 e s
ZN flPPLZCfiTIGN, KG/Hfl
o
01
UJ
0 >
- o
o
IUJ
+ «QC
io
Figure 41. Estimated zinc recovery by pearl millet.
-------
Georgia experiments. The nitrogen content of forages generally decreases
with age, so that harvesting more frequently may increase total N uptake.
Particular attention should be called to K uptake (Figure 36). It was
estimated that pearl millet had a large capacity to recover K, and at low
application rates exhibited some deficiency. Supplemental K could be bene-
ficial in this range. Effluent appears to supply other elements in sufficient
quantities (Figures 37-41) since recoveries were below 100%.
With adequate moisture and nutrients pearl millet should be harvested
3 or 4 times during the growing season. At 400 kg/ha (360 Ib/acre) applied N,
forage yield of 10 mton/ha (4.5 tons/acre) was estimated (Figure 23). The
corresponding yield of greenchop (17% dry matter) was 59 mtons/ha (26 tons/
acre).
Corn Silage
Dry yields and N uptake (Figures 42 and 43) from this study agreed with
results from Alexander et al. (1963), but were somewhat below those of Robert-
son et_ aJL (1965) and Gonske and Keeney (1969). Uptake of N by corn is-more
efficient in bands than in broadcast application, as in effluent irrigation.
Crop uptake estimates of P, K, Ca and Mg (Figures 44-46) agreed closely with
those of Alexander et_ aj_. (1963). Estimates of Fe and Zn concentrations
(Figures 49 and 50) of 0.020% and 0.0050%, respectively, were in the range of
other results (Linsner, 1970). All the elements were adequate (Figures 42-
50), except K.
Since corn silage has a short growing season (10-14 weeks), it could be
followed with another summer crop (such as soybeans).
Estimated forage yield at 200 kg/ha (180 Ib/acre) applied N were 5 mtons/
ha (2.2 tons/acre), from Figure 42. The corresponding yield of greenchop
(20% dry matter) was 25 mtons/ha (11 tons/acre).
Corn Grain
Estimated yields of corn grain are given in Figure 51. These values
agreed closely with those of Stanley and Rhoads (1971) in Florida and Jung
e_t aj_. (1972) in Wisconsin. Nitrogen uptake estimates (Figure 52) from this
study were below those of Jung _et aj_. (1972), for two reasons. First, the
Wisconsin soil had a slightly higher base fertility than the Florida soil.
Second, corn intercepts more of the nitrogen banded application than for
broadcast, as in effluent irrigation. This same effect was noted above for
corn silage.
Estimates of other elements are given in Figures 53-59. Other nutrients
appeared to be present in adequate quantities. However, at 25 mm/week corn
ears did not fill out completely in the 1973 season, indicating possible K
deficiency under extended production of corn at low application rates. Sup-
plemental K might be necessary under these conditions.
71
-------
CT
I
o
o
cc
-------
0
200 100 ©00 ©00
N flPPLICflTION, KG/Hfl
Figure 43. Estimated nitrogen recovery fay corn silage.
-------
-I h—H h-—I h- 1-
X
o
LU O.
CE
i—
a. •
a- S-
_ .o
^^tf>
..o >
yj
oc
_o
E-CEIVERY
1-
-I h
50 100 ISO 200
P flPPLICflTIGN, KG/Hfl
2SO
Figure 44, Estimated phosphorus recovery by corn silage.
-------
S
o
UJ O,
V S1
CC
j__
Q_ •
^ h
4—H h 1 I-
ECOVERt
i I
i|0 80 tao 160
K flPPLICflTIONf KG/Hfl
o
o
fM
O
o >
2 o
.O
200
Figure 45. Estimated photassium recovery by corn silage.
-------
CTl
o
Q-
ID
cr S
•4- h- h
-I 1 1 1 J-
UPTflKE
-•»
RECOVERY
-I
300 600 300 1200
Cfl flPPLICflTIGN, KG/Hfl
*>
cc
yj
>
o
o
1SOO
Figure 46. Estimated calcium recovery by corn silage.
-------
CT _
X
o
*
LU O.
CE
I—
ID
O £
^—h—\—h—h
.0 >
"OB o
o
o
I
I I
300 100
MG flPPLICflTION, KG/Hfi
500
Figure 47. Estimated magnesium recovery by corn silage.
-------
CO
O
cc
H—
a.
3
CT
300 @00 900 1200
Nfl flPPLICflTEON, KG/Hfl
1500
Figure 48, Estimated sodium recovery by corn silage.
-------
+-T-H 1 1- 1 1- 1 1 1
o
5?._
_o
CM
RECOVERY
_JA
CC
UJ
. .0 >
- o
o
UJ
-f- cc
UJ
•f-BA U_
-S h—H h-—h-—+—I h-—I-
•o
6 12 18
FE RPPLICflTION, KG/Hfl
30
Figure 49, Estimated iron recovery by corn silage.
-------
CD
O
? *
X *
o
*
oj ej_
cc
I—
a. T
^—h—i—i—i—-+
^ \-
_o
ru
UPTflKE
. .o
CC
LU
LU
fiC
- HM>
RECOVERY
h 1 h
2 « 6 8
ZN flPPLICfiTION, KG/Hfi
10
•o
Figure 50. Estimated zinc recovery by corn silage.
-------
* O.
CL
IT
co
o
H 1- \-
•h—f-
100 200 300 &IOO
N flPPLICflTIGN, KG/Hfl
SOO
Figure 51. Estimated yield response by corn grain.
-------
00
ro
O
cc
o. .
irt-8-
OJ
.0 >
o
yj
• cc
RECOVERY
I I
300 " 600 " 900
N flPPLICfiTION,
4—+
-o
1500
Figure 52, Estimated nitrogen recovery by corn grain.
-------
CO
00
o
A
yj
-i h
•§
oc
UJ
.o >
SF o
O
yj
50 100 ISO
P flPPLICflTION, KG/Hfl
2SO
Figure 53. Estimated phosphorus recovery by corn grain.
-------
CO
X
o
CE
h-»
CL.
4 h—f
4 h 1 h- h
h 1- 1-
UPTfiKE
UJ
50 " 100 ISO 200
K flPPLICflTION, KG/Hfl
RECOVERY
4—4
250
Figure 54, Estimated potassium recovery by corn grain.
-------
00
en
cc
o
0
H h 1 1-
UPTflKE
cc
UJ
>
o
RECOVERt
-I—I-
300
+
600 800 1200
flPPLICfiTION, KG/Hfi
isoo
Figure 55, Estimated calcium recovery by corn grain,
-------
00
X
yj oJL
0
I i
i I
UPTRKE
CC
yj
>
o
o
yj
O
RECOVERY
4,
III!
SOO 200
HG flPPLICflTION, KG/Hfl
500
Figure 56. Estimated magnesium recovery by corn grain.
-------
co
en
x
o
cr
i—
o_
a: £+
•{ 1 h
UPTflKE
H 1 1 \-
300 eoo soo 1200
Nfl fiPPLICflTION, KG/Hfl
RECOVERY
-h—I-
CC
UJ
>
o
C_)
UJ
Figure 57. Estimated sodium recovery by corn grain.
-------
CO
CO
CE
l_
£L
LU
LL.
S2 S8
FE flPPLICflTION, KG/Hfl
Figure 58. Estimated iron recovery by corn grain.
-------
00
UD
.
fu
a:
x •
o
*
LU
-1 h
I I
ZN FtPPLICfiT
ECOVERY
f I
tr:
yj
10
Figure 59. Estimated zinc recovery by corn grain.
-------
For N application of 200 kg/ha (180 Ib/acre), the yield of dry corn was
8 mtons/ha (3.6 tons/acre), from Figure 51. For a moisture content of 15%,
this corresponded to 9.4 mtons/ha (150 bu/acre).
Kenaf
Dry matter yields of kenaf showed weak coupling with application rate
(Figure 60). Estimates based on the present study were below those of Pepper
and Prine (1969), but in both cases only one harvest was obtained with Ever-
glades 41 variety. Killinger (1967) reported similar yields to those of
Pepper and Prine (1969) with this variety. The study of Killinger (1967)
showed a nitrogen content of 2.0% at 123 kg/ha applied N, compared to an
estimated value of 1% or less at that rate for this study. Apparently N up-
take by kenaf was much weaker under broadcast application than banded appli-
cation, as used by Killinger (1967). This probably accounted for low recovery
efficiencies (Figure 61) estimated from the present work. As with other
crops, K uptake exceeded application at lower rates (Figure 63), indicating
a possible need for supplemental K. Karbassi and Killinger (1966) showed a
positive response of kenaf to K addition. Kenaf also showed high demand for
Fe (Figure 67). All elements, except K, were supplied in adequate quantities
(Figures 60-68).
A yield of 6 mtons/ha (2.7 tons/acre) of dry forage was estimated at
250 kg/ha (220 Ib/acre) of applied N (Figure 60). This corresponded to 33
mtons/ha (15 tons/acre) of greenchop at 18% dry matter.
Rye
Dry matter yield showed an appreciable increase with application rate
(Figure 69). These estimates of yield agreed closely with results of Morris
and Jackson (1959) and Morris and Reese (1962) in Georgia. Nitrogen uptake
(Figure 70) also agrees closely with values from Parks et_ _al_. (1970). As
with several of the summer crops, at lower application rates, rye shows K
uptake exceeding application (Figure 72). This indicates potential K defi-
ciency and need for supplemental K. Other elements appear to be supplied in
adequate quantities (Figures 70-77). Beneficial effects of the trace elements
Fe and Zn (Figures 76 and 77) occur, since appreciable fractions of these are
taken up by the rye.
With adequate moisture and nutrients, rye should be harvested about 3
times. Since the yield of dry forage at 160 kg/ha (140 Ib/acre) applied N
was 3.5 mtons/ha (1.6 tons/acre) from Figure 69, the corresponding yield of
greenchop (20% dry matter) was 18 mtons/ha (7.8 tons/acre).
Ryegrass
Estimates of dry matter yields (Figure 78) agreed closely with results
from Mislevy and Dantzman (1974) in Florida. Uptake of N (Figure 79) also
agreed with Mislevy and Dantzman (1974). Nitrogen content of 2.5 to 3.5% is
in the range given by Hylton ejt al_. (1965), and showed an increase with
application rate. Content of other nutrients estimated here were: P = 0.75,
K = 1.5, Ca = 0.5 and Mg = 0.25%. Values reported for these elements by
90
-------
CE
X
z
LU
O
CE
cc
QC
Q
a§0 SOO 750 I
N flPPLICfiTION, KG/Hfl
Figure 60. Estimated yield response of kenaf.
-------
250 500 750 JOOD
N RPPLICfiTIOM, KG/Hfl
1250
Figure 61. Estimated nitrogen recovery by kenaf.
-------
^ - f» -
1 - 1
X £
o
A
LU c
CE
a, SH-
0
Rl
-I h-—I- h—H h-—I h
@0 160 240 320
P fiPPUCfiTIGN, KG/Hfl
flC
LU
.0 >
W o
o
LU
Figure 62. Estimated phosphorus recovery by kenaf.
-------
&
g
a. • •
+•—f—+
RECOVERY
120 160
K RPPLICflTIQN, KG/Hfl
O
o
cc
o
LLJ
200
Figure 63. Estimated potassium recovery by kenaf.
-------
cn
200 HOO ©00 800
Cfl fiPPLICFSTION, KG/Hfl
Figure 64. Estimated calcium recovery by kenaf.
-------
LD
CTl
60 120 ISO 210
MG flPPLICflTION, KG/Hfl
300
Figure 65. Estimated magnesium recovery by kenaf.
-------
©_
a:
x
o
I S
0
-I—h
4—4 \—4 h
--40 .X
RECOVERY
I I I —I -+
250 SCO 750 1000
o
o
Figure 66. Estimated sodium recovery by kenaf.
-------
UD
cx>
§ 9 12
FE fiPPLICftTlON, KG/Hfi
Figure 67. Estimated iron recovery by kenaf.
-------
X
o
Qu "f
s s
B 8
•i S
UPTRKE
4- >-
01
UJ
__o >
4J
yj
RECOVERY
•o
S
ZN fiPPLICflTION, KG/Hfl
Figure 68. Estimated zinc recovery by kenaf.
-------
o
o
-------
o
o-
-------
o
cc o
o
«
UJ o.
cr
H.
a. •
Q. S'
UPTRKE
+-—I-—f
I 1 B I
T'(*» «^
«
>-
(DC
•° >
O
- cc
_ Q.
130 180
P flPPLICflTION, KG/Hfi
300
Figure 71. Estimated phosphorus recovery by rye.
-------
o
CO
o
o-
SCr
o
H h
4-—I h—h
O
-o
UPTflKE
o
-O
O
yj
1- cc
O ^
RECOVERY
•f
30 ©0 " 90 " 120
K flPPLICRTION, KG/Hfl
150
Figure 72. Estimated potassium recovery by rye.
-------
o
-pa
0
ISO 320 i|80 PIG
Cfl flPPLICRTIQN, KG/Hfi
Figure 73. Estimated calcium recovery by rye.
-------
o
Ol
e> _ i
OjTr
O
o ,
O
o-
4- h
. .o ^8
^^» *>?
UPTflKE
RECOVERY
i i i I
+—I-
50 " 100 " ISO " 260
MG fiPPLICflTION, KG/Hfl
.o
sr
..o >
Ol *Hs
LLJ
o
Figure 74. Estimated magnesium recovery by rye.
-------
o
CTl
o
«t
UJ S.
cr
^-
Q_
CE ^
S I
4- S-
ECOVERY
1 - 1
+
1-
H 1-
200 400 ©00 800
Nfl flPPLICflTION, KG/Hfl
.n >
o O
CJ
Figure 75. Estimated sodium recovery by rye.
-------
AJ-
4™ h—+
fi
X
o
UJ
CL -'
U.
UPTflKE
J-S *Xe
JLo
yj
RECOVERY
2 1 § 8
FE flPPLICRTION, KG/Hfi
so
Figure 76. Estimated iron recovery by rye.
-------
H 1 1 i—\ \ 1 h—f
o
oo
2E a
UPTRKE
-
oc
uu
.0 >
fa w-i
RECOVERY
i—i—i-
' 2 ' "1 ' t
ZN RPPLICflTION, KG/Hfl
-o
Figure 77. Estimated zinc recovery by rye.
-------
O.
UJ
o
cr
C£
O
u_
oc
Q
0
8 ! 1 h-—h-—h—fr-
4—1 1 I h—I -I- 1-
320
ftPPUCfiTIQN, KG/Hfl
800
Figure 78. Estimated yield response of ryegrass.
-------
or
o
UJ
IT
Figure 79. Estimated nitrogen recovery by ryegrass.
-------
S-
o
d
I—
a.
^ - 1
o
i - 1 - 1 - 1
UPTflKE
CC
yj
.o >
yj
f cc
. 0,
ECQiERY
4- S 1
•o
120 1
P RPPLICflTIONf KG/Hfl
Figure 80. Estimated phosphorus recuvery by ryegrass.
-------
o
4O-
CC o
x
o
CC
H-
a_
I I i h
o
-o
UPTflKE
o
-o
£C
O
O
UJ
cc
e
RECOVERY
H 4-
30 ©0 90 120
K flPPLICflTION,
ISO
Figure 81. Estimated potassium recovery by ryegrass.
-------
+-—I h—+
o. _
Q- S-
. .O
cc
LU
O
LU
•A
I I
8 1 B
480
640
Cfl flPPLICflTION,
@00
Figure 82. Estimated calcium recovery by ryegrass.
-------
-h
0
I „ I.., ,. p i „,. I L I .1 1 ., 1
50 ' 100 ISO Pnn ^e
•O
e"i
HG flPPLICflTION, KG/Hfl
Figure 83. Estimated magnesium recovery by ryegrass.
-------
CT o
ISin
0>
X
o
«.
UJ O.
cz
g-
0
WFFflKE
•2 ^
|S> «X
*!
>-
cc
J_o >
RECOVEflY
200 100
800
ICflTION, KG/Hfl
Figure 84. Estimated sodium recovery by ryegrass,
-------
o
ID
yj
i i -—i—+
,o
UIPTRKE
RECOVERY
CJ
LU
-~S u-
; I l
4—-f
FE
Figure 85. Estimated iron recovery by ryegrass,
-------
QC
O
O. --
-I h ! h 1
-§ i^
O
yj
£C
z
RECOVERY
^—h—h—i—i
1 2 3
IH flPPLICRTION, KG/Hfl
4—+
•o
Figure 86. Estimated zinc recovery by ryegrass.
-------
Parks and Fisher (1958) were approximately: P = 0.25%, |< = 3.0%, Ca = 0.7% and
Mg = 0.5%. These differences probably reflected differences in chemical
ratios applied, soil characteristics and crop variety. As with rye, K uptake
exceeded application (Figure 81) at the lower rates, indicating potential
deficiency and need for supplemental K. Other elements appeared to be avail-
able in adequate amounts (Figures 79-86). A beneficial effect was provided
by Fe and Zn as with rye.
Three cuttings would be expected. At 160 kg/ha (140 Ib/acre) of applied
N, yield of dry forage was estimated to be 4 mtons/ha (1.8 tons/acre) from
Figure 78. The corresponding yield of greenchop (15% dry matter) was 27
mtons/ha (12 tons/acre).
GROWTH RESPONSE OF CROPS
Introduction
In 1972, field experiments were conducted to measure plant growth and
nitrogen uptake with age under effluent irrigation. The crops studied and
their varieties are listed in Table 23. Plots were 30 m x 30 m (100 ft x
100 ft). Irrigation rates were 50, 100, 150 and 200 mm/week at an intensity
of 13 mm/hr (0.5 in./hr) following the schedule in Table 24. All plots were
prepared by disking, plowing and disking. All crops were planted on April 23,
1972 in 0.9 m x 30 m (3 ft x 100 ft) rows. Seeding rates were as follows:
corn 17 kg/ha, sorghum x sudangrass - 11 kg/ha and kenaf - 11 kg/ha. Begin-
ning in the fourth week after planting, duplicate samples, 91.5 cm x 91.5 cm
in size, were clipped from each plot. Samples were weighed, chopped, dried at
70°C for 24 hours, and weighed again. Composite samples were ground in a
Wiley mill and triplicate 0.500 g samples were analyzed for Kjeldahl_N (USEPA
1971). Composite effluent samples were collected each week and analyzed for
Kjeldahl-N (USEPA, 1971) and for N03-N.
Some aspects of this study have been discussed elsewhere (Overman and
Nguy, 1975 and Overman, 1975).
Results
Measurements and estimates were made of green weight, dry matter content,
dry weight, nitrogen content, nitrogen uptake and nitrogen recovery. Esti-
mates were made of harvest time for optimum nitrogen recovery.
Corn - Pioneer 3369 A
Forage data were collected for irrigation rates of 50, 100, 150 and 200
mm/week. Yield of green forage increased with age (Table 25-28). Dry matter
content showed a concurrent increase, while N content decreased (Figure 87a).
The crop showed a resultant increase in dry forage with age and also with
irrigation rate (Figure 87b). These trends have been reported by Bar-Yosef
and Kafkafi (1972).
118
-------
TABLE 23. CROPS AND VARIETIES USED IN GROWTH STUDY
Crop Variety
Corn Pioneer 3369A
McNair 440V
Sorghum x sudangrass Asgrow Grazer S
Kenaf Everglades 41
TABLE 24. IRRIGATION SCHEDULE FOR GROWTH STUDY
Rate Dose Application
mm/week mm/irrigation day of week
50 50 Wed.
100 50 Tues., Thurs.
150 50 Mon., Wed., Fri.
200 50 Mon., Tues., Thurs., Fri
119
-------
TABLE 25. GROWTH RESPONSE OF CORN (PIONEER 3369A) AT 50 MM/WEEK
Age
days
0
25
32
39
47
53
60
67
77
84
95
Green
Weight
mton/ha
0
0.41
1.12
2.00
5.72
14.7
20.6
31.6
30.5
25.9
50.0
Dry
Matter
%
11.8
12.2
11.7
12.2
10.6
12.0
16.4
20.8
24.4
21.4
Dry
Weight
mton/ha
0
0.048
0.14
0.23
0.70
1.56
2.48
5.19
6.34
6.31
10.7
N
%
_
3.36
3.68
2.64
2.71
1.51
1.50
1.25
0.95
1.11
1.70
N
kg/ha
0
1.6
5.1
6.1
19
24
37
65
60
70
182
TABLE 26. GROWTH RESPONSE OF CORN (PIONEER 3369A) AT 100 MM/WEEK
Age
days
0
25
32
39
47
53
60
67
77
84
95
Green
Weight
mton/ha
0
0.48
2.21
5.28
12.0
27.5
43.5
52.5
59.4
64.8
65.4
Dry
Matter
%
12.5
11.1
10.3
9.7
11.0
13.6
14.6
19.6
22.4
20.0
Dry
Weight
mton/ha
0
0.060
0.24
0.54
1.16
3.02
5.91
7.65
11.6
14.5
13.1
N
%
3.36
3.48
3.28
2.88
_
1.85
1.28
1.22
1.06
1.41
N
kg/ha
0
2.0
8.3
18
33
_
109
98
141
154
185
120
-------
TABLE 27. GROWTH RESPONSE OF CORN (PIONEER 3369A) AT 150 MM/WEEK
Age
days
0
25
32
39
47
53
60
67
77
84
95
Green
Weight
mton/ha
0
0.54
2.01
4.20
12.9
25.8
41.1
48.3
69.0
87.0
64.4
Dry
Matter
%
12.1
10.4
10.2
10.2
9.0
12.2
13.8
19.4
25.8
20.3
Dry
Weight
mton/ha
0
0.065
0.21
0.43
1.32
2.32
5.00
6.67
13.4
22.5
13.1
N
%
3.43
3.37
3.27
2.30
_
2.44
1.49
1.31
1.33
1.28
N
kq/ha
0
2.2
7.1
14
30
_
122
99
175
300
168
TABLE 28. GROWTH RESPONSE OF CORN (PIONEER 3369A) AT 200 MM/WEEK
Age
days
0
25
32
39
47
53
60
67
77
84
95
Dry
Weight
mtons/ha
0
0.65
2.04
5.16
16.1
31.0
43.0
62.8
75.0
99.8
70.0
Dry
Matter
%
18.5
14.1
11.2
11.0
9.8
15.2
14.0
16.4
20.0
17.6
Dry
Weight
mton/ha
0
0.12
0.29
0.58
1.77
3.04
6.53
8.80
12.3
20.0
12.3
N
%
_
3.61
3.71
3.37
2.52
2.32
2.63
1.31
1.29
1.51
1.46
N
kg/ha
0
4.3
11
20
45
70
172
115
159
302
180
121
-------
EO 50 HM/HEEK
O 200
lid 60
flGE, DfiTS
100
Figure 87. Response of nitrogen content, dry weight and
nitrogen recovery for corn (Pioneer 3369A).
122
-------
TABLE 29. ESTIMATED YIELD AND NITROGEN RESPONSE OF CORN
(PIONEER 3369A) AT 50 AND 200 MM/WEEK
Age
days
30
35
40
45
50
55
60
65
70
75
80
85
90
N
%
3.80
3.40
3.00
2.60
2.25
1.95
1.70
1.50
1.35
1.25
1.20
1.15
1.10
50
Dry
Weight
mton/ha
0.05
0.2
0.5
1.1
1.8
2.7
3.7
4.7
5.8
7.1
8.3
9.7
mm/week
N
kg/ha
2
6
13
25
35
46
56
64
73
85
96
107
200
Dry
Weight
mton/ha
0.3
0.7
1.4
2.3
3.7
5.6
7.6
10.0
12.7
15.7
18.8
22.1
mm/week
N
kg/ha
10
21
36
52
72
95
114
135
159
188
216
242
TABLE 30. ESTIMATED NITROGEN RECOVERY BY CORN
(PIONEER 3369A) AT 50 AND 200 MM/WEEK
50 mm/week
Age
days
35
40
45
50
55
60
65
70
75
80
85
90
Harvested
kg/ha
2
6
13
25
35
46
56
64
73
85
96
107
Applied
kg/ha
90
103
116
129
142
155
168
180
193
206
219
232
Recovered
%
2
6
11
19
25
30
33
36
38
41
44
46
200 mm/week
Harvested
kg/ha
10
21
36
52
72
95
114
135
159
188
216
242
Applied
kg/ha
360
412
464
516
568
620
672
720
772
824
876
928
Recovered
%
3
5
8
10
13
15
17
19
21
23
25
26
123
-------
Due to the scatter obtained for both N content and dry weights, smooth
curves were visually fitted to the data. A single curve was used for N con-
tent (Figure 87a), while separate curves were drawn for dry weights (Figure
87b). Values from these curves were then used to estimate N uptake with age
(Table 29). Applied N from planting to a particular age was estimated from
the average N content of the effluent for the crop season, irrigation rate
and time of irrigation. Recovery of N was then calculated as the ratio of
harvested to applied (Table 30). Recovery increased with age and was lower
for 200 mm/week than for 50 mm/week (Figure 87c). This latter result is in
agreement with yield data presented above. For 50 mm/week, recovery effi-
ciency reached approximately 50% at 90 days. The crop had not reached
maximum N recovery, even at 90 days.
Corn - McNair 440 V
Green and dry forage yields increased with age and irrigation rate
(Tables 31-34). Dry matter content rose, while N content declined with age.
Nitrogen uptake showed a general increase with age and irrigation rate.
Estimates of N content were obtained from Figure 88a. Similarly, esti-
mates of dry forage were taken from Figure 88b for 50 and 200 mm/week. These
values were then combined to estimate N uptake (Table 35). Nitrogen recovery
was finally calculated (Table 36) for 50 and 200 mm/week. Recovery increased
with time (Figure 88c) and was higher at the lower application rate. The
corn approached its maximum N recovery at 80 days, but never reached 50%.
Sorghum x Sudangrass
Samples were only collected for the first harvest period. Green and
dry forage yields increased with age and irrigation rate (Tables 37-40), while
N content showed a decrease. Crop uptake of N increased with age and with
irrigation rate.
Estimates of N content (Figure 89a) and dry weight (Figure 89b) were
combined to calculate N uptake at 50 and 200 mm/week (Table 41) and N recovery
(Table 42). Recovery increased with age (Figure 89c), and reached a peak
around 65 to 70 days. Efficiency of recovery was greater for the lower irri-
gation rate, but only reached approximately 25%.
From these results a harvest age of around 9 weeks appears optimum for
the first cutting.
Kenaf
Yields of green and dry forage increased with age and with irrigation
rate (Table 43-46). Even though N content decreased"with age, N uptake showed
an increase with age and irrigation rate. Estimates of N content (Figure 90a)
and dry weight (Figure 90b) for 50 and 200 mm/week were combined to calculate
N uptake by kenaf (Table 47). Nitrogen recovery was then calculated (Table
48) with age at 50 and 200 mm/week. Curves of N recovery (Figure 90c) showed
definite peaks around 70 days, reaching 30% recovery for 50 mm/week and only
about 10% for 200 mm/week. Optimum harvest time appears to be about 10 weeks.
124
-------
TABLE 31. GROWTH RESPONSE OF CORN (.MCNAIR 44oy) AT so MM/WEEK
Age
days
0
26
33
40
48
54
61
68
77
85
Green
Weight
mton/ha
0
0.22
0.68
2.05
9.12
9.39
13.3
20.1
21.0
22.1
Dry
Matter
%
13.5
11.5
19.0
12.8
15.8
18.4
15.4
19.4
21.2
Dry
Weight
mton/ha
0
0.030
0.078
0.39
1.17
1.48
2.45
3.10
4.07
4.68
N
%
3.61
4.09
2.58
3.07
1.46
3.17
0.89
1.33
0.78
N
kg/ha
0
1.1
3.2
10
36
22
78
28
54
37
TABLE 32. GROWTH RESPONSE OF CORN (MCNAIR 440V) AT 100 MM/WEEK
Age
days
0
26
33
40
48
54
61
68
77
85
Green
Weight
mton/ha
0
0.25
1.78
3.33
13.6
18.4
37.9
40.5
51.8
37.3
Dry
Matter
%
11.9
11.4
13.1
10.4
11.4
15.8
12.4
19.6
20.0
Dry
Weight
mton/ha
0
0.030
0.20
0.44
1.41
2.10
5.99
5.02
10.2
7.46
N
%
.
3.89
3.63
3.35
3.02
1.94
2.51
1 .35
1.57
-
N
kg/ha
0
1.2
7.3
15
42
41
150
68
160
-
125
-------
TABLE 33. GROWTH RESPONSE OF CORN (MCNAIR 440V) AT 150 MM/WEEK
Age
days
0
26
33
40
48
54
61
68
77
85
Green
Weight
mton/ha
0
0.35
1.94
3.04
10.3
22.0
48.0
45.6
41.2
47.3
Dry
Matter
%
11.9
11.7
12.0
10.4
10.8
15.0
14.0
19.2
19.8
Dry
Weight
mton/ha
0
0.042
0.23
0.36
1.07
2.38
7.20
6.38
7.91
9.36
N
%
_
4.29
4.15
3.77
2.87
2.55
1.84
1.53
1.85
-
N
kg/ha
0
1.8
10
14
31
61
132
211
146
—
TABLE 34. GROWTH RESPONSE OF CORN (MCNAIR 440V) AT 200 MM/WEEK
Age
days
0
26
33
40
48
54
61
68
77
85
Green
Weight
mton/ha
0
0.31
1.01
2.36
7.83
19.4
30.3
42.5
56.7
46.6
Dry
Matter
%
23.1
13.6
15.7
7.9
13.6
14.6
13.4
14.8
17.6
Dry
Weight
mton/ha
0
0.072
0.14
0.37
0.62
2.64
4.42
5.70
8.39
8.20
N
%
3.18
4.30
3.71
2.05
2.97
1.09
1.39
1.21
_
N
kg/ha
0
2.3
6.0
14
13
78
48
79
102
_
126
-------
UJ o.
> 01
o
CJ Q
III ,_=
CC
HH/WEEK
50
200
GE
CB)
S 50 MM/WEEK
O 200
m
Cfl)
I B 1 !
60
Figure 88. Response of nitrogen content, dry weight and
nitrogen recovery for corn (McNair 440V).
127
-------
TABLE 35. ESTIMATED YIELD AND NITROGEN RESPONSE OF CORN (MCNAIR 440V)
AT 50 AND 200 MM/WEEK
Age
days
30
35
40
45
50
55
60
65
70
75
80
N
%
4.00
3.50
3.05
2.65
2.30
1.95
1.70
1.50
1.35
1.25
1.10
50
Dry
Weight
mton/ha
0.2
0.5
0.8
1.2
1.6
2.1
2.6
3.2
3.8
4.5
mm/week
N
kg/ha
_
7
15
21
28
31
36
39
43
48
54
200
Dry
Weight
mton/ha
_
0.3
0.6
1.1
1.9
2.8
3.9
5.1
6.4
7.8
9.3
mm/week
N
kg/ha
.
11
18
29
44
55
66
77
87
98
112
TABLE 36. ESTIMATED NITROGEN RECOVERY BY CORN (MCNAIR 440V)
AT 50 AND 200 MM/WEEK
Age
days
35
40
45
50
55
60
65
70
75
80
Harvested
kg/ha
7
15
21
28
31
36
39
43
48
54
Applied
kg/ha
90
103
116
129
142
155
168
180
193
206
Recovered
%
8
15
18
22
22
23
23
24
25
26
Harvested
kg/ha
11
18
29
44
55
66
77
87
98
112
Applied
kg/ha
360
412
464
516
568
620
672
720
772
824
Recovered
%
3.1
4.4
6.2
8.5
9.7
11
11
12
13
14
128
-------
TABLE 37. GROWTH RESPONSE OF SORGHUM X SUDANGRASS
AT 50 MM/WEEK
Age
days
0
27
34
41
49
55
62
69
Green
Weight
mton/ha
0
0.29
1.01
2.62
5.52
12.2
27.1
19.6
Dry
Matter
%
_
16.3
14.8
8.0
13.2
14.0
16.0
16.6
Dry
Weight
mton/ha
0
0.047
0.15
0.21
0.73
1.71
4.34
3.25
N
%
3.99
3.67
3.41
2.62
1.74
1.37
1.28
N
kg/ha
0
1.9
5,5
7.2
19.1
30.0
59.5
41.6
TABLE 38. GROWTH RESPONSE OF SORGHUM X SUDANGRASS
AT 100 MM/WEEK
Age
days
0
27
34
41
49
55
62
69
Green
Weight
mton/ha
0
0.25
1,36
3.70
8.52
17.8
25.7
35.2
Dry
Matter
%
15.4
14.1
8.9
11.8
15.0
15.0
14.6
Dry
Weight
mton/ha
0
0.015
0.19
0.33
1.00
2.67
3.86
5.14
N
%
.
4.39
4.05
3.19
2.75
2.00
1.60
1.42
N
kg/ha
0
0.66
7.7
10.5
27.5
53.4
61.8
73.0
129
-------
TABLE 39. GROWTH RESPONSE OF SORGHUM X SUDANGRASS
AT 150 MM/WEEK
Age
days
0
27
34
41
49
55
62
69
Green
Weight
mton/ha
0
0.34
1 .49
3.25
8.46
17.1
29.7
35.8
Dry
Matter
%
_
15.8
12.9
9.4
15.2
15.2
15.8
16.0
Dry
Weight
mton/ha
0
0.054
0.19
0.31
1.29
2.60
4.69
5.73
N
%
.
4.21
3.69
3.75
2.87
2.30
1.60
1.53
N
kg/ha
0
2,3
7.0
11.6
37.0
59.8
75.0
87.7
TABLE 40. GROWTH RESPONSE OF SORGHUM X SUDANGRASS
AT 200 MM/WEEK
Age
days
0
27
34
41
49
55
62
69
Green
Weight
mton/ha
0
0.43
1.44
3.47
8.64
21.8
32.4
37.4
Dry
Matter
%
12.7
13.3
7.5
10.6
14.8
14.6
18.0
Dry
Weight
mton/ha
0
0.054
0.19
0.26
0.92
3.22
4.73
6.73
N
%
4.93
3.95
3.75
2.52
2.41
1.53
1.32
N
kg/ha
0
2.7
7.5
9.8
23.2
77.6
72.4
88.8
130
-------
+-—h
S*
oc
UJ Os
> «
O
tJ »
200
(B)
CE
X
50 HM/WEEK
?00
ffl
/
©'
/
O,
4—f
4—f
no
flGE, DflTS
too
Figure 89. Response of nitrogen content, dry weight and
nitrogen recovery for sorghum x sudangrass.
131
-------
TABLE 41. ESTIMATED YIELD AND NITROGEN RESPONSE OF SORGHUM X SUDANGRASS
AT 50 AND 200 MM/WEEK
Age
days
30
35
40
45
50
55
60
65
70
75
N
%
4.50
3.90
3.40
2.90
2.40
2.00
1.65
1.35
1.15
1.00
50
Dry
Weight
mton/ha
0.10
0.15
0.25
0.50
0.85
1.40
2.10
2.90
3.70
4.65
mm/ week
N
kq/ha
5
6
9
15
20
28
35
39
41
47
200
Dry
Weight
mton/ha
0.25
0.40
0.80
1.40
2.20
3.20
4.35
5.65
7.00
8.55
mm/ week
N
kg/ha
9
16
27
41
53
64
72
76
81
86
TABLE 42. ESTIMATED NITROGEN RECOVERY BY SORGHUM X SUDANGRASS
AT 50 AND 200 MM/WEEK
Age
days
30
35
40
45
50
55
60
65
70
75
50
Harvested
kg/ha
5
6
9
15
20
28
35
39
41
47
mm/week
Applied
kg/ha
77
90
103
116
129
142
155
168
180
193
Recovered
%
6
7
9
13
16
20
23
23
23
24
200
Harvested
kg/ha
9
16
27
41
53
64
72
76
81
86
mm/week
Applied
kg/ha
308
360
412
464
516
568
620
672
720
772
Recovered
%
3
4
7
9
10
11
12
12
11
11
132
-------
TABLE 43. GROWTH RESPONSE OF KENAF AT 50 MM/WEEK
Age
days
0
28
35
42
50
56
63
70
78
85
98
Green
Weight
mton/ha
0
0.51
1.34
5.75
6.72
11.0
12.7
26.8
28.5
27.2
45.5
Dry
Matter
%
_
11.8
11.2
11.6
13.4
12.4
16.0
8.0
15.4
15.8
18.6
Dry
Weight
mton/ha
0
0.060
0.15
0.67
0.90
1.36
2.03
2.14
4.39
4.30
8.46
N
%
4.89
4.24
3.17
3.27
2.73
1.73
1.86
1 .58
1.42
1.23
N
kg/ha
0
2.9
6.4
21.2
29.4
37.1
35.1
39.8
69.4
61.1
104.0
TABLE 44. GROWTH RESPONSE OF KENAF AT 100 MM/WEEK
Age
days
0
28
35
42
50
56
63
70
78
85
98
Green
Weight
mton/ha
0
0.47
1.70
7.70
8.58
13.9
18.6
24.6
28.6
28.0
51.9
Dry
Matter
%
_
11.4
10.2
6.8
8.5
10.8
15.0
9.4
18.2
19.4
16.8
Dry
Weight
mton/ha
0
0.054
0.17
0.52
0.73
1.50
2.79
2.31
5.21
5.43
8.72
N
%
_
5.03
4.44
3.38
3.03
2.89
1.94
1.81
1.92
2.28
1.72
N
kg/ha
0
2.7
7.5
17.6
22.1
43.4
54.1
41 .8
100.0
124.0
150.0
133
-------
TABLE 45. GROWTH RESPONSE OF KENAF AT 150 MM/WEEK
Age
days
0
28
35
42
50
56
63
70
78
85
98
Green
Weight
mton/ha
0
0.68
1.96
7.34
9.96
12.6
12.4
21.4
16.5
27.8
42.3
Dry
Matter
%
__
10.7
10.1
6.5
6.1
11.2
14.2
9.6
19.8
21.6
15.6
Dry
Weight
mton/ha
0
0.073
0.20
0.47
0.61
1.41
1.76
2.05
3.27
6.00
6.60
N
%
_
3.78
3.72
3.35
3.35
3.56
2.18
1.74
1.15
1.25
2.60
N
kg/ha
0
2.8
7.4
15.7
20.4
50.2
38.4
35.7
37.6
75.0
172.0
TABLE 46. GROWTH RESPONSE OF KENAF AT 200 MM/WEEK
Age
days
0
28
35
42
50
56
63
70
78
85
98
Green
Weight
mton/ha
0
0.83
2.46
6.43
11.1
16.2
22.2
26.5
32.7
40.3
51.1
Dry
Matter
%
10.1
10.0
10.8
8.4
11.0
13.0
10.6
16.0
17.8
16.7
Dry
Weight
mton/ha
0
0.080
0.25
0.69
0.93
1.78
2.89
2.81
5.23
7.17
8.53
N
%
4.88
4.24
2.79
4.19
3.17
2.22
1.10
3.12
2.84
1.90
N
kg/ha
0
3.9
10.6
19.2
39.0
56.4
64.2
30.9
163.0
204.0
162.0
134
-------
I ! I I
yj 0
a:
CB)
m 50 HM/WEEK
o eoo
^JU
Q
o-
©
•E
I 1 I
o
4—4
fflp-
• ED
1
60
DflTS
100
Figure 90. Response of nitrogen content, dry weight and
nitrogen recovery for kenaf.
35
-------
TABLE 47. ESTIMATED YIELD AND NITROGEN RESPONSE OF KENAF
AT 50 AND 200 MM/WEEK
Age
days
30
35
40
45
50
55
60
65
70
75
80
85
90
95
N
%
4.75
4.35
3.95
3.55
3.20
2.85
2.50
2.25
1.95
1.70
1.50
1.35
1.20
1.10
50
Dry
Weight
mton/ha
0.06
0.18
0.30
0.55
0.90
1.30
1.75
2.25
2.85
3.45
4.05
4.70
5.35
6.00
mm/week
N
kg/ha
3
8
12
20
29
37
44
51
56
59
61
63
64
66
200
Dry
Weight
mton/ha
0.10
0.25
0.45
0.80
1 .20
1.70
2.35
3.10
3.90
4.85
5.80
6.85
7.90
8.95
mm/ week
N
kg/ha
5
11
18
28
38
48
59
69
76
82
87
92
95
98
TABLE 48. ESTIMATED NITROGEN RECOVERY BY KENAF
AT 50 AND 200 MM/WEEK
50 mm/week
Age
days
30
35
40
45
50
55
60
65
70
75
80
85
90
95
Harvested
kg/ha
3
8
12
20
29
37
44
51
56
59
61
63
64
66
Applied
kg/ha
77
90
103
116
129
142
155
168
180
193
206
219
232
245
Recovered
%
4
9
12
17
22
26
28
30
31
31
30
29
28
27
200 mm/week
Harvested
kg/ha
5
11
18
28
38
48
59
69
76
82
87
92
95
98
Applied
kg/ha
308
360
412
464
516
568
620
672
720
772
824
876
928
980
Recovered
%
1.6
3,1
4.4
6.0
7.4
8.5
9.5
10.3
10.6
10.6
10.6
10.5
10.2
10.0
136
-------
Summary
The crops studied showed a lag time of 30-40 days in their growth
curves. Rag!and et_ al_. (1965) reported similar results with corn. Dry matter
yield increased with age, while N content decreased. Bar-Yosef and Kafkafi
(1972) observed similar response with corn. Nitrogen recovery by the crops
showed a continual increase throughout the study period. Estimates were made
of harvest age for optimum N recovery (Table 49). For Pioneer 3369 A corn
TABLE 49. ESTIMATED HARVEST AGE FOR OPTIMUM NITROGEN RECOVERY
Crop Age, weeks
Corn
Pioneer 3369 A >13
McNair 440V 12
Sorghum x Sudangrass 9
Kenaf 10
this value exceeded 13 weeks, with 14 weeks being a good estimate. The value
for sorghum x sudangrass represented the first harvest only. The second
harvest would be about the same, while the third harvest would cover a shorter
period due to reduced growth later in the season.
Effluent irrigation had two beneficial effects on crop growth - addition
of nutrients and reduction of soil moisture stress. Higher levels of applied
N produced greater uptake of N, in agreement with findings of Parks et al.
(1970). Parks and Knetsch (1959) observed higher yields at reduced moisture
tension. However, N recovery efficiency decreased with application rate,
with 50% recovery obtained at approximately 50 mm/week (2 in./week).
GROWTH RESPONSE OF TREES
Field plots were established at Tallahassee by W. H. Smith and D. M.
Post, School of Forest Resources and Conservation, University of Florida.
The study was aimed at screening several species as to their suitability for
wastewater irrigation on well drained sandy soil. Growth response was
measured on several species (Table 50) over a three year period (Sinith and
Evans, 1977, and Smith et al_., 1978).
Tree heights were measured 1, 2 and 3 years after planting. Average
values from the three plots receiving 50, 100 and 200 mm/week were averaged
and graphed to show growth trends (Figures 91-94). Cottonwood showed the
most rapid growth (Figure 91) during the 3-year period. Cottonwood, sycamore,
black locust, green ash, Chinese elm, and tulip poplar exhibited linear growth
137
-------
(Figures 91 and 92). Sweetgum, bald cypress and red cedar showed decreasing
growth rates (Figure 93), while loblolly pine showed a rapid increase in
growth rate during the 3-year period.
All of the species reported appeared to be suitable for effluent irri-
gation.
TABLE 50. TREES IRRIGATED AT TALLAHASSEE
Common Name
Scientific Name
Cottonwood
Sycamore
Black locusts
Green ash
Chinese elm
Tulip poplar
Sweetgum
Bald cypress
Red cedar
Loblolly pine
penn6 yl.vaYii.ca
Taxodium dJJ>£L
AuA A
tazda
138
-------
0_
CO
to
Figure 91. Growth response of Cottonwood, Sycamore
and Black Locust to effluent irrigation,
-------
1/1
GREEN R5H
CHINESE EL
TULIP PDPLRR
Figure 92. Growth response of Green Ash, Chinese Elm
and Tulip Poplar to effluent irrigation.
-------
CD BflLD CYPRESS
RED CEDflR
Figure 93. Growth response of Sweetgum, Bald Cypress
and Red Cedar to effluent irrigation.
-------
Figure 94.
Growth response of Loblolly Pine to
effluent irrigation.
-------
SECTION 7
ANALYSIS OF TRANSPORT PROCESSES
INTRODUCTION
Laboratory experiments were conducted to clarify the interplay among
various processes operating in the field system. Attention was focused on
phosphorus and cations (including NH^) because of their particular importance
to water quality and to plant growth. Crop response under effluent irrigation
was influenced by the availability of N, P and K in the soil solution for crop
uptake through the root system. For N and K this availability was related to
cation exchange - transfer between solution and surface phases. For P, anion
exchange and chemical reaction were the critical factors. Measurements were
made to quantify the rates of some of the processes and to establish correla-
tions among the processes of convection, dispersion, exchange and chemical
reaction. In both phosphorus fixation and cation exchange, mathematical models
were developed of transport and kinetic components to provide an analytical
framework. Results from these laboratory studies were used to aid in explain-
ing field results.
PHOSPHORUS TRANSPORT
In Section 5 it was observed that phosphorus in wastewater applied to
land decreased in concentration as the water percolated down through the soil,
and that ammonium acetate extractable phosphorus also decreased with depth.
Two models were developed to quantify the relevant processes involved. Cho
et al_. (1970), Novak et al_. (1975), Novak and Adriano (1975) and Monke et_ aJL
TT974) previously applied the theory of convective diffusion to phosphorus
movement in soil. This analysis focused on the coupling among the various
processes and quantified the kinetics of fixation in this study of effluent
irrigation.
Flow experiments were conducted in a packed-bed reactor. The reactor was
constructed from acrylic plastic 4.7-cm ID and 10 cm in length. End plates
were grooved to allow uniform entry and exit of solution. Filter paper was
used at each end to confine the soil. Sampling ports were installed at depths
of 2, 4, 6 and 8 cm. Lakeland fine sand was dried in a forced air oven at
105°C for 24 hours and then packed into the reactor to a bulk density of 1.73
g/cm3. The reactor was then purged with C02 gas to displace other gases,
followed by saturation with degassed distilled water. Stock solution of
KH2P04 containing 10 mgA P was fed to the reactor with a peristaltic pump at
pore velocities of 0.118, 0.256, 0.539 and 0.900 cm/min. Flow was continued
until phosphorus concentration reached a steady value. Orthophosphate was
determined by the stannous chloride reduction method (APHA, 1971).
143
-------
Equilibrium Model
This model included four processes: convection, dispersion, adsorption
and reaction. Concentration in a volume increment changed due to convection,
or mass flow, of the solution through the increment. Concentration gradients,
partly due to nonuniform flow velocity in the pores, caused mixing due to
diffusion. Adsorption and desorption at particle surfaces induced changes in
solution concentration. Finally, chemical reactions, in solution or on the
particle surfaces, caused changes in solution concentration. A dispersed flow
model of this system for one dimension was given by (Smith, 1970):
D^4- 7|f - er - e ff-- e |f = 0 0)
r, £ O Z O L d t
d Z
where C = solute concentration in the liquid phase
z = depth in the bed
t - time
r = chemical reaction
S_ = solute concentration in the adsorbed phase
JD = dispersion coefficient for the bed
V = volume flux through the bed
e = porosity of the bed
Here V was taken as constant with depth and time. A first order chemical
reaction with coefficient k was assumed so that
r = kC (2)
Equilibrium adsorption was assumed to be linear with exchange coefficient R
so that
S = RC (3)
The utility of these assumptions for the packed bed reactor was determined
from the experimental results. Combination of Equations (1) - (3) yielded
2
D i_C _ v |C _ kc _ (] + R) 9C = Q (4)
9z^ dz 8t
where D = D/e and V = V/e were pore dispersion coefficient and pore velocity,
respectively. Initial and boundary conditions to be used in the system were
(5)
(6)
(7)
z
z
z
>
=
->
0
0
00
C
C
C
= 0
= C
0
+ 0
t
t
t
=
>
>
0
0
0
144
-------
where C0 was the feed concentration for the reactor. This system of equations
was reduced to the dimension! ess form
with
? > o
5 = 0
^ +00
$ = 0
<}> = 1
cf> -> 0
T - 0
T .> 0
T > 0
(9)
(10)
(11)
where
5=4 T=°
a 2D B *\I D
using £ as a characteristic length. The steady state and transient solutions
were, respectively, (Overman et al., 1976)
!>s = exp [ - ( \|a + 3 - a) 5 J (12)
and
- 1 exp [ - ( Ja2 + 3 a) U x
[ exp (2 a2 + 32 C) x e^fc ( + J (a2 + 32) T )
j(a2 + 32)t') ] (13)
where subscript s refers to steady state and e/rfc represents the complimentary
error function. It was convenient for purposes of analysis to define the
dimensionless variables
r— v _ T _ /-, , . x V2 t
and the dimensionless parameter
32 _ 4kD
Y = "T = -7.2
a V
145
-------
Equations (12) and (13) were then converted to the form
, =exp r. +Y- z]
5 H + Y'
and
^- = {[ exp(2Z)
+ eAfc (—=,- 17 ) ] (15)
2/<}>s = C/CS versus T
with Z as a parameter, or, C/CS versus Z with T as a parameter. With no
chemical reaction (k = 0), Y = 0 and Cs = C0 for all depths, as expected.
For the special case Y < < 1, it was shown by Taylor series expansion
that Equation (14) reduced to
C
^= exp (-|z) (16)
o
and that
7 ~ * 7 T ~ —
L 2D 4D 1 + R
Steady state distributions are shown in Figure 95 for the four veloc-
ities. Distributions were logarithmic as predicted by Equation (12). Values
of the reaction coefficient k were estimated from the slopes of these lines
using Equation (16). The dependence of k on velocity is illustrated in
Figure 96a.
Estimates of D and R were obtained from the transient data. Equation
(15) was fitted to data as follows. From a plot of C/CS versus t for a parti-
cular depth and velocity, estimates were made of times tQt2, to,5 and to.7
corresponding to C/CS = 0.2, 0.5 and 0.7, respectively. Values'of To.2/T0.5
and TO.7 were obtained for these same values of C/CS from Equation (15) for a
range of values of Z. The value of Z which satisfied the equality
T0.7 " T0.2 t0.7 " ^.2
T0.5 ^.5
was selected as the proper value. An estimate of D was then obtained from
D - Vz/2Z. For example, with z = 2 cm and V = 0.118 cm/min, Z = 9.6
146
-------
0,10
111 <0
0.118 CM/MI ML
Figure 95. Steady state distributions of phosphorus
for the packed-bed reactor.
147
-------
X
f\J
o ~.
O'
gj-
©
cc
.. (fl)
I
O
4 1 I I
0.10 0.60
V, CM/MIN
Figure 96. Dependence of reaction, exchange and dispersion coefficients
on velocity for the equilibrium model of phosphorus transport
148
-------
was obtained. The corresponding value of D was 0.012 cm2/min. At each
velocity the four values of D were averaged. Variation of D with velocity
1s shown in Figure 96c. From the definitions of Z and T it was shown that
Z2 z2
L -
_ _
T D*t '
where D* = D/(l + R). Estimates of D* were obtained by substituting appro-
priate values Into Equation (17). For example, with z = 2 cm and V = 0.118
cm/mi n, Z = 9.6 and T0 .5/t(j.5 = 0.0076 1/min, so that D* = 0.00033 cm2/min.
It follows that R = 361 At each velocity the four values of R were averaged.
The trend of R with velocity is shown in Figure 96b.
The various coefficients showed strong dependence upon pore velocity.
An asymptotic increase in k with V was apparent (Figure 96a). This suggested
that the reaction was not homogeneous (solution phase) as implied in the
model, but was heterogeneous (solid phase) and that k approached a limiting
value at higher velocities. At the lower velocities reaction was limited by
diffusion of reactants to the particle surface (Smith, 1970). Variation of
R with V (Figure 96b) indicated that adsorption and desorption coefficients
had different velocity dependence, so that their ratio changed with velocity.
At higher velocities this ratio approached a constant value, which implied
that their velocity dependence assumed similar form in the upper range.
Dependence of both k and R on V brought the equilibrium assumption into ques-
tion, which led to the global model, as discussed in the next section. Levich
(1962) pointed out that surface reactions should be included as a boundary
condition. However, geometric complexity of the solution/solid interface
necessitated including these effects as a sink term. The dispersion coeffi-
cient showed a more-than-linear increase with velocity (Figure 96c). Bear
(1972) has discussed some of the proposed correlations between D and V,
including linear and quadratic types. The observed dependence reflected in
part description of a multi-dimensional transport by a one-dimensional model.
The assumption that y« 1 was justified, since Y= 0.0163, 0.0122,
0.0112 and 0.0108 at velocities of 0.118, 0.256, 0.539 and 0.900 cm/min,
respectively, were calculated from appropriate values of k and D. This
simplified the calculations considerably.
As mentioned in Section 5, a field plot was irrigated continuously for
three days in July, 1970 at an intensity of 1.25 cm/hr. At the end of three
days, soil solution samples were collected and analyzed for orthophosphate.
The distribution was logarithmic (Figure 13), as predicted above. The slope
of the regression line was 0.0401 I/cm. For this velocity, a water content of
0.16 was estimated from Overman and West (1972). The corresponding pore
velocity was estimated to be V = 0.13 cm/min. From Equation (16) the rate
constant was calculated to be k = (0.0401 )(0. 13) = 0.0052/min. This value
agreed closely with the corresponding value from Figure 96a.
The dispersed flow model with equilibrium exchange and first order
chemical reaction agreed closely with both steady state and transient results.
Observed steady state distributions were logarithmic, as predicted. Reaction
149
-------
coefficients for laboratory and field studies agreed rather closely. However,
correlations of reaction and exchange coefficients with velocity suggested
that the assumption of equilibrium between solution and adsorbed phases was
not entirely justified. A more detailed description of the surface component
seemed desirable.
Kinetic Model
In this model the assumption of equilibrium between solution and surface
phases was removed and the chemical reaction was assumed to occur on the par-
ticle surface. Thus the problem became one of heterogeneous kinetics (multi-
phase system) in contrast to homogeneous kinetics (single phase system). For
equilibrium exchange, the heterogeneous system may be treated as an equivalent
homogeneous system. This explains the apparent success of the equilibrium
model discussed above. The kinetic component for this model was written in
the global sense (Smith, 1970), i_.e_. without regard to intermediate steps
between bulk solution and the adsorbed phase. This implicitly assumed that
transfer to and from surfaces was kinetically controlled and not limited by
external diffusion. By assuming reversible adsorption followed by an essen-
tially irreversible reaction on the surface, the kinetic scheme was written as
kd
where A = solute concentration in adsorbed phase
F = solute concentration in fixed phase
ka = adsorption coefficient
k^ = desorption coefficient
kr = reaction coefficient
Adsorption, desorption and reaction were all assumed to follow first order
kinetics and the kinetic equations were written as
—— = k C - k A (19)
and
|£ = k C - k,A - k A (20)
d L d U r
Concentration of the adsorbed phase was expressed on a solution volume basis.
The transport equation for one-dimensional dispersed flow was written as
150
-------
Initial and boundary conditions were
z>0 C = 0 t = 0 (22)
z = 0 C = C0 t >: 0 (23)
z + » C -> 0 t >: 0 (24)
z>0 A = 0 t = 0 (25)
In the development of the model the dispersion term was neglected. Justifi-
cation for this follows below. Equations (19) and (21) were combined to give
3 r 3 r
V— + °-5±+kf-kA = n (?fi}
v 3z 9t V KdM u uo;
where V = V/e.
Steady state distributions were obtained
As = KCS (27)
and
Cs = CQ exp ( -y- z ) (28)
where
K = IT-XTT- (29)
and
k = krK (30)
For the case of no adsorption (ka = 0) the equations yielded As = 0 and
Cs = C0, as expected. With adsorption, but no reaction (kr = 0), the results
were Cs = C0, as expected.
By using definitions
* - _ A* = z* = t* =
Cs As Z £
kO I/
H 9 a
a = k~ K B = TiT
a
151
-------
Equations (26) and (20) were written as
i- aB(C* - A*) = 0 (31)
and
!££•= B(C* - A*) (32)
subject to the conditions
z* > 0 C* = 0 t* = 0 (33)
z* = 0 C* = 1 t* .> 0 (34)
z* + oo C* + 0 t* >: 0 (35)
z* > 0 A* = 0 t* = 0 (36)
Overman et al. (1978) solved Equations (31) - (36) and obtained
exp(-3 ) I \| 4a32z*y dy (37)
"s ~ "
and
~~ = A
7^ = •£- + exp(-agz*) exp[ - 3(t* - z*)] I J 4ag2z*(t* - z*)' (38)
s
and
-r- = £-= 0 t* < z* (39)
Hs us
where I0 was the modified Bessel function of first kind and zeroth order. For
a system with no adsorption (a = 0), Equation (38) reduced to plug flow, viz.
t < C = 0 (40)
t>f C = CQ (41)
as expected.
Values for k and kj were estimated from the transient data. From a
graph of C/CS versus t, the time corresponding to C/C$ = 0,5 was estimated.
Then t* was calculated, using the appropriate pore velocity and sampling
depth. Then K = t* - 1 was assumed. With kr «kd, this gave ka/kd = t* - 1
152
-------
Values of ka and kj were then chosen, subject to this constraint, until the
calculated curve agreed with the data. This procedure was followed for all
depths and velocities.
The model predicted a logarithmic distribution at steady state, as given
by Equation (28). By using the slopes from Figure 95 , estimates were ob-
tained for kr from Equation (30). This relationship established the relation-
ship between the apparent coefficient for the homogeneous reaction and the
coefficient for the heterogeneous reaction.
All three kinetic coefficients varied with velocity (Figure 97). Since
each curve showed asymptotic response, an empirical equation
k = km [ 1 -exp(-XV) ] (42)
was fitted for each process, where km and X were curve fitting parameters.
The resulting equations were:
m
k = 3.12 [1 - exp(-3.71 V)] (43)
a
kd = 0.170 [1 - exp(-2.71 V)] (44)
and
kr = 0.000520 [1 - exp(-2.53 V)] (45)
These equations indicated that the rates followed the order adsorption >
desorption > reaction. Since R for the equilibrium model was related to k
and k . for the kinetic model by
R = r*- (46)
kd
Equation (46) was used to calculate R for various velocities. The values
were 23.9, 23.5, 20.6 and 19.0 at 0.118, 0.256, 0.539 and 0.900 cm/min,
respectively. The decrease in R with V was related to the different velocity
dependence of k and k ,.
In the kinetic model, a global scheme was used which neglected any inter-
mediate steps between bulk solution and adsorbed phases. An alternative pos-
sibility was that transfer from solution to the surface was diffusion limited
(Smith, 1970) in which case solution concentration adjacent to the particle
surface was lower than in bulk solution. At higher velocity mass transfer
(by diffusion) was greatly enhanced, so that adsorption became the limiting
step. This coupling, then, gave rise to asymptotic increase of the global
coefficients to maxima. This line of analysis is being continued in another
study.
153
-------
O
Figure 97. Dependence of adsorption, desorption e»nd reaction coefficients
on velocity for the kinetic model of ph.osph.orus transport,
-------
Characteristic times for the processes of convection, dispersion,
adsorption, desorption and reaction were defined from Equations (19) - (21).
The times were:
convection T = — (47)
dispersion T = -g- (48)
adsorption T = -r— (49)
a
desorption T = 1— (50)
reaction T = — (51)
r Kr
These values were calculated for the 2-cm depth, where dispersion showed the
greatest relative importance. Values of D from the equilibrium model and
the kinetic coefficients from the kinetic model were used. Comparison of
values in Table 51 showed that dispersion and reaction were slow compared to
convection, adsorption and desorption. Hence, neglecting these terms in the
transient analysis was justified. Of course, reaction was relevant to the
steady state analysis. The insignificance of dispersion was also indicated
by the fact that at one pore volume C/CS was less than 0.01 for all cases.
Analysis of phosphorus transport with the kinetic model gave good
description of both steady state and transient response. The model predicted
a logarithmic distribution at steady state, as was observed experimentally
both in the laboratory and the field. Estimates of adsorption, desorption
and reaction coefficients showed that all three varied in an asymptotic manner
with velocity. It was concluded that at lower velocities mass transfer to
the particle surface was diffusion controlled, while at higher velocities
surface kinetics was controlling. Calculation of characteristic times showed
that dispersion was negligible compared to the other processes, which justi-
fied use of Equation (26).
PHOSPHORUS KINETICS
Batch studies were conducted to elaborate the details associated with
the kinetic scheme, Equation (18), used in the kinetic model of phosphorus
transport. Since this model assumed that phosphate molecules were adsorbed
onto a surface, then the number of adsorption sites per molecule was an impor-
tant parameter in the process.
Various aspects of phosphorus fixation in soils were discussed previously
by Hemwall (1957), Ulrich et al_. (1962), Hsu (1964), Tandon and Kurtz (1968),
Rajan and Fox (1972), Probert and Larsen (1972), and Kuo and Lotze (1974).
155
-------
TABLE 51. VALUES OF RATE COEFFICIENTS AND
CHARACTERISTIC TIMES AT 2-CM DEPTH
Parameter
V
D
ka
kd
kr
cm/mi n
cm
1
1
1
2
/min
/min
/min
/min
0.
0.
1.
0.
0.
118
0122
10
031
00013
Numerical Value
0.
0.
2.
0.
0.
256
0329
00
079
00024
0.
0.
2.
0.
0.
539
0515
75
110
00039
0.
0.
3.
0.
0.
900
239
00
184
00046
16.9
328
0.91
32
7700
7.8
122
0.50
13
4200
3.7
78
0.36
9
2600
2.2
17
0.33
5
2200
156
-------
In all the rate studies reported, a two-stage sequence was observed—a fast
initial drop in solution phosphate followed by a slower decrease. Probert and
Larsen (1972) concluded that the fast step resulted from exchange between
solution and solid phases, while the slower step reflected incorporation of
phosphorus into the solid phase. Hsu (1964) concluded that the fast step
related to adsorption of phosphate onto colloidal aluminum hydroxide and iron
hydroxide in the soil and that the slow step was caused by adsorption of
phosphate onto surfaces of hydroxides and oxides which formed during the
experiment.
Enfield and Bledsoe (1975) applied several kinetic models in estimating
phosphorus fixing capacity of soils.
Development of the Model
Preliminary experiments were conducted in a batch reactor with several
combinations of soil mass and initial concentration of phosphorus. If the
kinetic model of Equation (18) was correct, then the graph of relative phos-
phorus concentration versus time should be unaffected by soil mass. It was
observed that changing the soil mass did shift the plot; viz, that increased
soil mass in the reactor increased the rate of disappearance of solution
phosphorus. This observation indicated that at least one step in the process
was not first order. In fact, the results suggested that adsorption could be
described by second order kinetics. The kinetic model adopted was (Overman
and Chu, 1977a)
ka kr
P + S^Z!: A —*- F + S (52)
kd
where P = concentration of phosphorus in solution
S = concentration of adsorptive sites in the soil
A = concentration of adsorbed phosphorus
F = concentration of fixed phosphorus
ka = kinetic coefficient for adsorption
kd = kinetic coefficient for desorption
kr = kinetic coefficient for reaction
All concentrations were expressed on a volume basis. Equation (52) repre-
sented a case of heterogeneous catalysis, and was recognized as an example of
Langmuir-Hinshelwood kinetics (Laidler, 1950). Adsorption was assumed to
follow second order kinetics, while desorption and reaction were assumed to
be first order processes. For a closed batch reactor the rate of gain of
phosphorus in solution was described by
3T • -kasp + kdA <53>
Because the nonlinear nature of Equation (53) presented difficulties for
obtaining a mathematical solution, it was decided to utilize an open reactor
with a steady input of phosphorus, r. The appropriate kinetic equations for
this reactor were:
157
-------
= r - kaSP + kdA (54)
and
^=kaSP- kdA-krA (55)
subject to
S = SQ - A (56)
where S0 was the total concentration of adsorptlve sites in the reactor.
Equation (56) resulted from the catalytic nature of Equation (52).
For steady state conditions Equations (54) - (56) reduced to
0 = r - kaSsPs + kdAs
and
0 = kaSsPs - (kd + kr> As (58)
Ss = S0 = As (59)
where subscript s referred to steady state. Combination of Equations (57) -
(59) yielded
Ss = £ (60)
i +F-hr ps
kd Kr s
and
r = k /k° S (61)
d * ^ + P
ka s
Using the definitions
k , + k
K = -4 r- (62)
Ka
and
rm = krSo (63)
158
-------
Equations (60) and (61) were reduced to
S
Ss = —V (64)
and
m s //-i-\
r = K + p (65)
s
It was noted that rm was the upper limit for r and that at P$ = K, r = rm/2.
The catalytic form of Equation (52) led to the hyperbolic relationship between
feed rate and steady state phosphorus concentration given by Equation (65).
In fact, achievement of a steady state required that Equation (52) be cata-
lytic in nature. Equation (65) showed the same form as the Michaelis-Menton
relationship in enzyme kinetics (Aiba et_ aj_., 1965).
Effect of Soil/Solution Ratio
Experiments were conducted in a batch reactor at 25°C and at a pH of 5. At
the beginning of each run a selected quantity of I^PCty was diluted to 500 ml
with deionized water, adjusted to pH = 5 and placed in the reactor. A
selected quantity of soil was then added to the reactor. During the experi-
ment a paddle stirrer kept the soil suspended while a solution of HgPCty was
injected into the reactor at a constant rate of 3.16 m£/hr with a syringe
pump. The pH was controlled at 5 with a two-way pH controller by suspending
the electrodes in the reactor. Checks of the electrodes at the beginning and
end of each run verified their stability. Lakeland fine sand was collected
from the 30-60 cm depth at Tallahassee in an area which had received neither
effluent nor fertilizer. This soil was known to contain < 5% silt, < 5% clay
and a large amount of iron and aluminum (Hortenstine, 1966). Experiments
were conducted with 100, 150, 200 and 250 g soil, which had been dried at
105°C in a forced air oven for 24 hr, in 500 ml of solution. Samples were
collected at 1/2-, 1-, 1 1/2-, 2-, 2 1/2-, 3-, 4-, 5-, and 6-hr periods and
immediately filtered through 0.45 ym Mi Hi pore filters, with prefilters to
remove larger particles, to stop the reaction and for chemical analysis. Ortho-
phosphate was determined by stannous chloride reduction (APHA, 1971). It was
found in preliminary experiments that beginning with a phosphate solution in the
reactor enhanced the approach to steady state. In all the runs phosphate
concentration in the reactor reached steady state within 2 hr. In several
cases, the syringe pump was stopped after 6 hr to show that phosphorus did
decay rapidly toward zero. Volumes added by the pump or removed by sampling
were negligible. Experiments were_conducted at pH = 5 so that essentially
all the phosphate occurred as
Equation (65) was used to fit the experimental data, using the weighted
statistical procedure of Wilkinson (1961). Four rates of phosphorus addition
were used for each soil/solution ratio. The data did follow the predicted
trends (Figure 98). Furthermore, the upper limit increased with soil mass,
159
-------
PS, H HOLE/L
Figure 98. Effect of soil mass on steady state phosphorus
fixation in the batch reactor.
-------
cr>
2SO
M, GH
Figure 99. Dependence on maximum phosphorus
fixation rate on soil mass.
-------
01
ro
M, GH
Figure 100. Dependence on equilibrium constant of phosphorus
fixation on soil mass.
-------
as predicted by Equation (13). The graph of rm versus soil mass showed a
linear increase (Figure 99 ), as predicted by Equation (63). However, the
graph showed a nonzero intercept. This suggested that the solution reaction
between phosphate and slightly soluble aluminum (Hsu, 1975) was significant.
At constant pH this reaction was expected to be first order in P. and inde-
pendent of soil mass. This effect was later verified. The equilibrium con-
stant was also shown to vary with soil mass (Figure 100). The reason for
this was not clear and remained unexplained.
Effect of pH
Additional steady state batch experiments were conducted to show the
dependence of rm and K on pH (Overman and Chu, 1977b ). Experiments were
conducted at pH = 2, 3, 5, 7 and 8. Four rates of phosphorus addition were
used at each pH. In all runs 250 g of Lakeland fine sand was used in 500 ml
solution. Stirring and pH control were as noted above.
Equation (65) was again used to fit the data (Figure 101). The analysis
gave values for rm and K at each pH. These curves at first appeared confus-
ing, however, further analysis revealed their meaning. Values of rm showed a
decrease with an increase in pH (Figure 102). This trend follows that
observed by Muljadi et al_. (1966), Chen et al_. (1973), Rajan ejt al_. (1974)
and Hsu (1975). Hsu~Tl975) suggested that OH" competed strongly with H2POZ
for adsorption by aluminum and iron compounds in the soil. The graph of 1/K
versus pH showed a distribution very similar to that of the H2P04 fraction
(Figure 103). For pH 2-8,H2P04 and HPO^ were the dominant forms of phosphate
This was interpreted to mean that ka changed with pH. The adsorption process
was written in terms of elemental P, but Figure 103 suggested that in fact
H£P07 was the relevant phosphate ion, by assuming that k= « H2P04- Muljadi
et. aL (1966) and Rajan et al_. (1974) also concluded that H2P04 was the form
involved in adsorption. The shift between distributions in Figure 10.3
resulted from the suspension effect of a pH value of approximately 0.2 in the
batch reactor.
Effect of Solution Reaction
In the analysis above the batch process was treated as heterogeneous
catalysis. Hsu (1975) showed that phosphate reacted in solution with alumi-
num. Consequently, Equation (54) was modified to include a first order
homogeneous reaction so that
dP = r _ k.p _ k sp + k.A (66)
dt ad
where k' was the first order rate coefficient (Overman and Chu, 1977c).
Equations (55) and (56) remained the same. For steady state conditions it
was shown that
r = k'p+ (67)
163
-------
CTl
M HOLE/L
Figure 101. Effect of pH on steady state phosphorus
fixation in the batch reactor.
-------
X
oc
I
N
o
(Ti
(jn
Figure 102. Dependence of maximum phosphorus
fixation rate on pH.
-------
CTi
x --
PH
o
10
Figure 103. Dependence of equilibrium constant
for phosphorus fixation on pH.
-------
where rm and K were defined as before. Using the definition
r1 = r - k'Ps (68)
Equation (67) was written as
r'- (69)
Equation (69) was of the same form as Equation (65), so rm and K were
evaluated by the same procedure as before.
Values of k1 were chosen until the plot of rm versus soil mass passed
through the origin. With k' = 0.003/hr the graph was linear and passed
through the origin. This result conformed with Equation (63), since the cor-
relation between S0 and soil mass was expected to be linear with a zero
intercept. The correlation between r and P5 (Figure 104) was described very
well by Equation (67). These curves did not approach maxima because of the
homogeneous reaction, which continued to increase with Ps.
Summary
The kinetics of phosphorus fixation was studied in a batch reactor
operated in the steady state mode. A kinetic model was developed which in-
cluded both heterogeneous and homogeneous processes. Langmuir-Hinselwood
kinetics was used to describe the heterogeneous process, while the homogeneous
component employed first order kinetics. Results from the steady state
experiments agreed with the assumption of heterogeneous catalysis. Apparently
adsorptive sites in the soil acted to catalyze chemical reaction between
phosphate and some other component. Results at different pH values identified
^04 as the pertinent phosphate ion involved in the heterogeneous step. The
expected linear correlation between the maximum rate of surface reaction and
soil was verified.
Dependence of phosphorus fixation on pH and soil mass was explained very
well with the proposed kinetic model. It did not estimate phosphorus fixation
capacity of soil. The very difficult task of identifying the chemical mecha-
nism was not achieved in this study.
In the model for phosphorus transport, the kinetic component assumed
first order kinetics, given by Equation (19). This assumption was justified
in the packed-bed reactor since an excess of adsorptive sites was present and
the number of adsorbed molecules was very small compared to the number of
sites. For this reason the second order process reduced to pseudo first
order.
CATION TRANSPORT
In the effluent irrigation system cation exchange was important in pro-
cesses such as nitrification (NH^-^NO^) and nutrient uptake by plants, A
model of cation transport was utilized to establish coupling between ion
167
-------
4—I— I \
CT)
OO
Ps, M HOLE/L
Figure 104. Effect of solution reaction on steady state
phorphorus fixation in a batch reactor.
-------
exchange and convection. Components of the model included convection, dis-
persion and cation exchange. Measurements were made on a univalent/univalent
system. The cations K+ and NH| were chosen because of their similar ionic
mobilities.
Cation Exchange Model
A reversible ion exchange model was assumed for the univalent-univalent
system (Hiester and Vermuelen, 1952)
kc
C + B • S —^ C - S + B (70)
kB
where C = solution concentration on the inflow cation
B = solution concentration of the outflow cation
C-S = surface concentration of the inflow cation
B-S = surface concentration of the outflow cation
k = exchange coefficient
and the subscript refers to the appropriate cation. Cation exchange was
assumed to be controlled by mass action, so that the kinetic equation
8C'S k,C (B-S) - kDB (C-S) (71)
Bt
was used, where t was the time. The analysis was simplified by assuming
constant and uniform ionic strength throughout the experiments, so that, by
electrical neutrality
B + C = A = constant (72)
where A was the solution concentration of anion. It was further assumed that
the cation exchange capacity of the soil, Q, was constant, so that
B-S + C-S = Q (73)
and
B + C = C0 (74)
where C0 was the feed concentration of the cation. Combination of Equations
(71) - (74) yielded
|9- = kcC (Q - q) - kB (C0 - C) q (75)
where q = C-S. The initial condition was
q = 0 at t = 0 (76)
169
-------
2 > 0
z = 0
Z + oo
C = 0
C = C0
C + 0
t = 0
t A 0
t J> 0
Solution of Equation (75) required an auxiliary relationship of some type.
For the packed-bed reactor this consisted of a mass balance for the cation in
the solution phase.
Cation Transport Model
A dispersed flow model (Smith, 1970) was used for the packed bed reactor,
and for one dimensional flow was written as
n 32C v 3C _ 3C p 3 (OS) /77x
UT7?3z~3t e 3t U/j
oZ
with the conditions
(78)
(79)
(80)
where z = depth in the reactor
D = pore dispersion coefficient
V = pore velocity
p = bulk density of soil
e = porosity.
In the analysis C'S was written as mass of cation/mass of soil. Equations
(75) - (80) constituted the system to be solved. However, it was convenient
to convert the system to dimensionless form with the definitions
r* = — n* - 3. 7* - z. +* _ vt
L* /> M """ ^ ^ /i L"~rt
C0 H Q £ I
n - A a - &kcCo a - .Pi K - kc
I n (-* P ~~ ~r- r\ ~ 1
VV V f~[ K
™ v V C-\t r\r\
0 B
where 1 was a characteristic length. Equations (75) - (80) were converted to
n 32C* _ 3C* = 3C^ + 3qj^ (81)
3z* 3z
with
(82)
(83)
(84)
170
z*
.z*
z*
> 0
- 0
-V OO
C* =
C
C
* =
* -V
0
1
0
t*
t*
t*
= 0
^ 0
n 0
-------
and
= a[C* (1 - q*) - 1 (] - C*) q* ] (85)
with
z* > 0 q* = 0 t* = 0 (86)
For the special case of symmetric exchange (kr = kR = k), Equation (85)
reduced to L b
a[C* - q* ] (87)
Equations (81) - (86) were solved by finite differences, using the Crank-
Nicolson implicit procedure (Gupta and Greenkorn, 1973).
Response Curves
Experiments were conducted in a packed-bed reactor, 4.8 cm ID and 10 cm
in length. The end plates were grooved to provide more uniform flow at the
ends. After drying in a forced air oven at 105°C for 24 hr, Lakeland fine
sand was packed in the reactor to a bulk density of 1.66 g/crn3 and porosity
of 0.376. After purging with C02 to displace insoluble gases, the reactor
was saturated with deionized water. Several pore volumes of 1 N NH^l were
passed through to saturate the exchange complex with NHj ions. This was
followed by several pore volumes of Nh^Cl solution of appropriate feed con-
centration and pH = 6.5. Flow rates were controlled with a peristaltic pump
with speed control. Whole discrete outflow samples were collected with a
fraction collector. Samples were analyzed for NH4 by spectrophotometer, K
by flame photometer and Cl~ by coulometric titration. Experiments were con-
ducted by switching between KC1 and NH^Cl of the same molar concentration
and at pH = 6.5. Measurements of Cl~ showed that its concentration remained
constant throughout a run. Measurements of the two cations established that
Equation (74) was satisfied.
Output curves were all of the type shown in Figure 105. The amount of
cation in exchange was estimated from a mass balance for the particular
cation; viz,
In + Pores (initial) = Out + Pores (final) + Exchange (88)
Mass 1n (moles) was calculated from feed concentration (moles/£), flow rate
(cnr/min) and total time (min). Mass-out was calculated from concentration
(moles/Jl) for the fraction, flow rate (cm3/min) and time between fractions
(min), and summing over all fractions. Mass in the pores was calculated from
concentration (moles/&) and pore volume (cm3). Exchange quantity was divided
by soil mass in the reactor to obtain Q (meq/100 g). Values were averaged
for the inflow and outflow cations to obtain a value of 0 for use in the model
In all cases inflow and outflow values were within 10% of each other. + In the
analysis, exchange was assumed to be symmetric (k^ = kg = k), since NH4 and K+
171
-------
IV)
C0 = 0.00983 IMOLES/L
V = 0. 117 CH/MIN
30
VT/L
Figure 105. Typical outflow curves for NH./K transport
in a packed bed reactor.
-------
both had the same Ionic diffusion coefficients, and Equation (87) was used.
Values for k and D were chosen to obtain good agreement between data and the
model. It was observed that the influence of dispersion was primarily limited
to the early portion of the curves. Exchange, on the other hand, influenced
the entire curve. Reversal of the cations with the same feed concentration
and velocity gave curves which superimposed throughout the runs, which showed
that exchange between NHj and K+ was symmetric.
Coupling of D and k with V
Response curves for a feed concentration of C0 - 0.01 moles/£ and veloc-
ities of 0.147, 0.297 and 0.588 cm/min all followed the shape of Figure 105,
and superimposed very closely over most of the curve. The early portions
disagreed slightly. A graph of the parameters showed that k versus V was
linear, while D versus V was quadratic (Figure 106). These correlations
explained the superimposition of the three output curves over the upper
portions.
The coupling between k and V was explained with elementary film theory
(Smith, 1970). In the above analysis, Equation (71) was written as a global
model, where solution concentrations represented bulk solution. Apparently
the transfer from bulk solution to the particle surface was diffusion limited,
so that solution concentration adjacent to the surface was lower than bulk
concentration. For this system surface kinetics was fast compared to diffu-
sion. This agreed with observations in a batch reactor where the character-
istic time was found to be less than one minute, which established that sur-
face kinetics of exchange was very fast. The diffusion limited transfer in
the packed-bed reactor caused a lag between surface and solution phases
(Figure 107). Lag was independent of velocity, due to linear coupling between
convection and cation exchange.
Feed Concentration and System Response
Behavior of the response curves was strongly influenced by feed concen-
tration (Figure 108). At low concentrations response time was governed by
exchange, while at high concentrations convection and dispersion were the
controlling processes. This behavior was inherent in the coupling between
Equations (81) and (87).
Ionic strength had a major influence on the exchange coefficient (Figure
109). The decrease in the exchange coefficient with increased ionic strength
probably resulted from compression of the electric double layer at the charged
particle/solution interface (Gast, 1977), which increased the concentration
gradient near the particle surface. This increased diffusion showed up as an
increased exchange coefficient in the global model.
Cation exchange capacity increased with ionic strength (Figure 109).
Melendez (1976) showed that this type of correlation was associated with
colloids of metal oxides and hydroxides which possessed surfaces of constant
potential rather than surfaces of constant charge. Hortenstine (1966) showed
that Lakeland fine sand contained large quantities of aluminum and iron
compounds.
173
-------
8
V, CH/HIN
Figure 106. Dependence of exchange and dispersion coefficients
on velocity for NH^/K+ transport.
-------
I I 1 I 1
fr— i i
01
Co • 0,00983 HOLiS/L
10
Figure 107. Lag between surface and solution concentration
for NHJ/K+ transport.
-------
0.00983
0.00499
0,00131
VT/L
Figure 108. Effect of feed concentration on outflow
curves for NH^/K transport.
-------
O'
,01
02
C0,
Figure 109. Effect of ionic strength on exchange coefficient and
cation exchange capacity for NHt/K transport.
-------
Summary
A transport model for the simple case of NH./K was developed using the
one dimensional dispersed flow equation and a reversible second order kinetic
equation for exchange. For these two cations exchange was shown to be sym-
metric. The model described output curves very well for all feed concentra-
tions and velocities. Coupling between the dispersion coefficient and veloc-
ity was shown to be quadratic, so that dispersion assumed greater importance
at higher velocities. Dependence of the exchange coefficient on velocity was
linear, which indicated that exchange was limited by diffusion of cations to
and from the particle surface. Batch measurements verified that surface
kinetics was fast compared to mass transfer in solution. These results sug-
gested that exchange of cations such as NHj and K+ under field conditions
was closely related to convection, i_._e, during irrigation exchange rates
increased and then slowed down after irrigation ceased and water percolation
rate diminished.
Several effects of feed concentration were noted. At low concentrations
response time was controlled by exchange, while at high concentration dis-
persion became more important. The role of feed concentration resulted from
the second order kinetics of exchange. The exchange coefficient decreased
with increased ionic strength, due to compression of the electric double
layer. Cation exchange capacity increased with ionic strength due to the
presence of colloids of aluminum and iron in Lakeland soil. Even for this
apparently simple system of NHj/K+ exchange, there was a complex interplay of
several factors in the system.
From these studies on cation transport and exchange it was concluded
that nitrification (bacterial conversion of exchangeable NH4 to NO^ ) would
be enhanced with higher solution concentration of NHt and in soils with higher
cation exchange capacity. This suggested that nitrogen uptake by the crops
at Tallahassee was limited by the low cation exchange capacity of Lakeland
fine sand (less than 5 meq/100 g) and that it was lower for the effluent
used (total N < 40 mg/£) than would have occurred with effluent of higher N
concentration.
178
-------
SECTION 8
REFERENCES
Adams, W. E., M. Stelly, H. D. Morris and C. B. Elkins. 1967. A comparison of
coastal and common bermudagrass in the Piedmont Region. II. Effect of
fertilization and crimson clover on nitrogen, phosphorus, and potassium
contents of the forage. Agronomy J., 59:281-284.
Agronomy Mimeo Report AG 71-5. 1971. 1970 sorghum-sudangrass and pearl millet
variety trials in Florida. University of Florida, Gainesville, Florida.
Aiba, S., A. E. Humphrey and N. F. Millis. 1965. Biochemical Engineering.
Academic Press, New York.
Alexander, R. A., J. F. Hentges, Jr., W. K. Robertson, G. A. Barden and J. T.
McCall. 1963. Composition and digestibility of corn silage as affected
by fertilizer rate and plant population. J. Animal Sci., 22:5-8.
American Public Health Association. 1971. Standard methods for the examina-
tion of water and wastewater. 13th ed. Washington, D.C.
Bar-Yosef, B. and U. Kafkafi. 1972. Rates of growth and nutrient uptake of
irrigated corn as affected by N and P fertilization. Soil Sci. Soc. Amer.
Proc. 36:931-936,
Bear, J. 1972. Dynamics of fluids in porous media. American Elsevier Pub-
lishing Co., New York.
Buckman, H. 0. and N. C. Brady. 1969. The nature and properties of soils.
7th ed. McMillan Co., New York.
Burton, G. W., J. E. Jackson and R. H. Hart. 1963. Effect of cutting fre-
quency and nitrogen on yield, in vitro digestibility, and protein, fiber,
and carotene content of coastal bermudagrass. Agronomy J., 55:500-502.
Carlile, B. L. and J. M. Stewart. 1977. Land application of waste water -
A bibliography. OWRT/WRSIC 77-204. Water Resources Scientific Informa-
tion Center, U. S. Department of Interior, Washington, D.C.
Carroll, T. E., D. L. Maase, J. M. Genco and C. N. Ifeado. 1975. Review of
landspreading of liquid municipal sewage sludge. PB-245 271. National
Technical Information Service, Springfield, Virginia.
179
-------
Chen, Y. P., J. N. Butler and W. Stumm. 1973. Kinetic study of phosphate
reaction with aluminum oxide and kaolinite. Env. Sci. and Techno!.,
7:327-332.
Cho, C. M., J. Strong and G. J. Racz . 1970. Convective transport of ortho-
phosphate (P-31 and P-32) in several Manitoba soils. Can. J. Soil Sci.,
50:303-315.
D'ltri, F. 1977. Wastewater renovation and reuse. Marcel Dekker, Inc.,
New York.
Elliot, L. F. and F. J. Stevenson (eds.). 1977. Soils for management of
organic wastes and wastewaters. American Society of Agronomy, Madison,
Wisconsin.
Enfield, C. 6. and B. E. Bledsoe. 1975. Kinetic model for orthophosphate
reactions in mineral soils. EPA-660/2-75-022. U.S. Environmental Pro-
tection Agency. Robert S. Kerr Environmental Research Laboratory. Ada,
Oklahoma. 133 pp.
Fiskell, J. G. A. and L. W. Zelazny. 1971. Acidic properties of some Florida
soils. I. pH-dependent cation exchange. Soil and Crop Sci. Soc. Fla.
Proc. 31:145-149.
Gast, R. G. 1977. Surface and colloid chemistry. In: Minerals in the soil
environment. J. B. Dixon and S. B. Weed (eds.). Soil Science Society of
America. Madison, Wisconsin.
Gonske, R. G. and D. R. Keeney. 1969. Effect of fertilizer nitrogen, variety
and maturity on the dry matter yield and nitrogen fractions of corn grown
for silage. Agronomy J., 61:72-76.
Gupta, S. R. and R. A. Greenkorn. 1973. Dispersion during flow in porous
media with bilinear adsorption. Water Resources Research, 9:1357-1368.
Hart, R. H. and G. W. Burton. 1965. Effect of row spacing, seeding rate, and
nitrogen fertilization on forage yield and quality of Gahi-1 pearl millet.
Agronomy J., 57:376-378.
Hartman, W. J., Jr. 1975. An Evaluation of land treatment of municipal
wastewater and physical siting of facility installations. AD-A016 118.
National Technical Information Service, Springfield, Virginia.
Hemwall, J. B. 1957. The fixation of phosphorus by soils. Advances in
Agronomy, 9:95-112.
Hendry, C. W., Jr. and C. R. Sproul. 1966. Geology and ground-water resources
of Leon County, Florida. Bulletin No. 47. Florida Geological Survey.
Tallahassee, Florida. 178 pp.
Hiester, N. K. and T. Vermuelen. 1952. Saturation performance of ion-exchange
and adsorption columns. Chem. Eng. Progress, 48:505-516.
180
-------
Hook, J. E., L. T. Kardos and W. E. Sopper. 1973. Effect of land disposal of
wastewaters on soil phosphorus relations. In: Recycling treated munici-
pal wastewater and sludge through forest and cropland. W. E. Sopper and
L. T. Kardos (eds.). Pennsylvania State University Press, University
Park.
Hortenstine, C. C. 1966. Phosphorus fixation and phosphorus fractions in
sandy soils. Soil and Crop Sci. Soc. Fla. Proc. 26:136-142.
Hortenstine, C. C. 1973. Studies on renovating sewage effluent through spray
irrigation at Eustis and at Walt Disney World. In: Landspreading Munic-
ipal Effluent and Sludge in Florida. A. R. Overman, L. B. Baldwin, L. C.
Hammond and D. W. Jones (eds.). University of Florida, Gainesville.
pp. 60-86.
Hoveland, C. S., W. B. Anthony and C. E. Scarsbrook. 1967. Effect of manage-
ment on yield and quality of sudax sorghum-sudan hybrid and Gahi-1 pearl
millet. Alabama Agr. Exp. Sta. Leaflet. 7 pp.
Hsu, P. H. 1964. Adsorption of phosphate by aluminum and iron in soils. Soil
Sci. Soc. Amer. Proc. 28:474-478.
Hsu, P. H. 1975. Precipitation of phosphate from solution using aluminum
salt. Water Research, 9:1155-1161.
Hylton, L. 0., Jr., A. Ulrich and D. R. Cornelius. 1965. Comparison of nitro-
gen constituents as indicators of the nitrogen status of Italian ryegrass,
and relation of top to root growth. Crop Sci., 5:21-23.
Jacobs, H. S., R. M. Reed, S. J. Thien and L. V. Withee. 1971. Soils labora-
tory exercise source book. American Society of Agronomy. Madison, Wis-
consin.
Johnson, R. D., R. L. Jones, T. D. Hinesly and D. J. David. 1974. Selected
chemical characteristics of soils, forages and drainage water from the
sewage farm serving Melbourne, Australia. U.S. Army Corps of Engineers,
Washington, D.C.
Jung, P. E., Jr., L. A. Peterson and L. E. Schrader. 1972. Response of
irrigated corn to time, rate, and source of applied N on sandy soils.
Agronomy J., 64:668-670.
Karbassi, P. and G. B. Killinger. 1966. Effect of macronutrients on growth
of kenaf. Soil and Crop Sci. Soc. Fla. Proc. 26:226-230.
Kardos, L. T., W. E. Sopper, E. A. Myers, R. R. Parizek and J. B. Nesbitt.
1974. Renovation of secondary effluent for reuse as a water resource.
EPA-660/2-74-016. Office of Research and Development, U.S. Environmental
Protection Agency, Washington, D.C.
181
-------
Killinger, G. B. 1967. Potential uses for kenaf. Soil and Crop Sci. Soc.
Fla. Proc. 27:4-11.
Killinger, G. B. 1969. Kenaf, a multi-use crop. Agronomy J., 61:734-736.
Kuo, S. and E. G. Lotse. 1974. Kinetics of phosphate adsorption and desorp-
tion by hematite and gibbsite. Soil Sci., 116:400-406.
Laidler, K. J. 1950. Chemical kinetics. McGraw-Hill Book Co., Inc., New
York.
Levich, V. G. 1962. Physicochemical hydrodynamics. Prentice-Hall, Inc.,
Englewood Cliffs, New Jersey.
Linsner, J. R. 1970. The animal nutrition implications in plant analysis.
In: Symposium on plant analysis. A. J. Ohlrogge, R. D. Munson and S. E.
Allred (eds.). International Minerals Corp., Skokie, Illinois.
Loehr, R. C. 1977. Land as a waste management alternative. Ann Arbor Science,
Ann Arbor, Michigan.
Melendez, M. J. A. 1976. Interpretive analyses of potentiometric titrations
of selected soils and colloidal components. M.S. Thesis. University of
Florida, Gainesville.
Metcalf and Eddy, Inc. 1972. Wastewater Engineering. McGraw-Hill Book Co.,
New York.
Mislevy, P. and C. L. Dantzman. 1974. Comparison of ammonium nitrate and
sulfur-coated urea on ryegrass production in south central Florida. Soil
and Crop Sci. Soc. Fla. Proc. 31:199-201.
Monke, E. J., E. D. Millette and L. F. Huggins. 1974. Movement of pollutant
phosphorus in unsaturated soil. Technical Report No. 46. Water Resources
Research Center. Purdue University, West Lafayette, Indiana. 41 pp.
Morris, H. D. and J. E. Jackson. 1959. Source and time of application of
nitrogen for rye forage. Soil Sci. Soc. Amer. Proc. 23:305-307.
Morris, H. D. and E. L. Reese. 1962. Effect of varying levels of nitrogen
on forage yields of several rye varieties and rye mixtures. Agronomy J.,
54:155-157.
Muljadi, D., A. M. Posner and J. P. Quirk. 1966. The mechanism of phosphate
adsorption by kaolinite, gibbsite, and pseudoboehmite: I. The isotherms
and the effect of pH on adsorption. J. Soil Sci., 17:212-229. 1966.
Novak, L. T. and D. C. Adriano. 1975. Phosphorus movement in soils: Soil-
orthophosphate reaction kinetics. J. Environ. Qual., 4:261-267.
Novak, L. T., D. C. Adriano, G. A. Coulman and D. B. Shah. 1975. Phosphorus
movement in soils: Theoretical aspects. J. Environ. Qua!., 4:93-99.
182
-------
Overman, A. R. 1975. Effluent irrigation of pearl millet. J. Env. Eng. Div.,
ASCE, 101:193-199.
Overman, A. R. 1978. Effluent irrigation of crops at different frequencies.
J. Env. Eng. Div., ASCE, (in press).
Overman, A. R. and R. L. Chu. 1977a. A kinetic model of steady state phos-
phorus fixation in a batch reactor - I. Effect of soil/solution ratio.
Water Research, 11:771-775.
Overman, A. R. and R. L. Chu. 1977b. A kinetic model of steady state phos-
phorus fixation in a batch reactor - II. Effect of pH. Water Research,
11:777-778.
Overman, A. R. and R. L. Chu. 1977c. A kinetic model of steady state phos-
phorus fixation in a batch reactor - III. Effect of solution reaction.
Water Research, 11:779-781.
Overman, A. R., R. L. Chu and Y. Le. 1978. Kinetic coefficients for phos-
phorus transport in a packed-bed reactor. J. Water Poll. Control Fed.,
50:1905-1910.
Overman, A. R., R. L. Chu and W. G. Leseman. 1976. Phosphorus transport in
a packed bed reactor. J. Water Poll. Control Fed., 48:880-888,
Overman. A. R. and L. E. Evans. 1978. Effluent irrigation of sorghum x sudan-
grass and kenaf. J. Env. Eng. Div., ASCE, (in press).
Overman. A. R. and A. Nguy. 1975. Growth response and nutrient uptake by
forage crops under effluent irrigation. Commun. Soil Sci. and Plant
Analysis, 6:81-93.
Overman, A. R. and H. M. West. 1972. Measurement of unsaturated hydraulic
conductivity by the constant outflow method. Trans. Amer. Soc. Agr.
Eng. 15:1110-1111.
Parks, W. L. and W. B. Fisher, Jr. 1958. Influence of soil temperature and
nitrogen on ryegrass growth and chemical composition. Soil Sci. Soc.
Amer. Proc. 23:257-259.
Parks, W. L. and J. L. Knetsch. 1959. Corn yields as influenced by nitrogen
level and drought intensity. Agronomy J., 51:363-364.
Parks, C. L., A. W. White and F. C. Boswell. 1970. Effect of plastic bar-
rier under the nitrate band on nitrogen uptake by plants. Agronomy J,,
62:437-439.
Pepper, G. E. and G. M. Prine. 1969. Corn, sorghum, kenaf and their mixtures
for silage. Soil and Crop Sci. Soc. Fla. Proc. 29:208-214.
183
-------
Pound, C. E., R. W. Crites and D. A. Griffes. 1975. Costs of wastewater
treatment by land application. EPA-430/9-75-003. Office of Water Program
Operations, U.S. Environmental Protection Agency, Washington, D.C.
Probert, M. E. and S. Larsen. 1972. The kinetics of heterogeneous isotopic
exchange. J. Soil Sci., 23:76-81.
Ragland, J. L., A. L. Hatfield and G. R. Benoit. 1965. The growth and yield
of corn. I. Microclimatic effects on growth. Agronomy J., 57:217-220.
Rajan, S. S. S. and R. L. Fox. 1972. Phosphate adsorption by soils: I.
Influence of time and ionic environment on phosphate adsorption. Comm.
Soil Sci. and Plant Anal., 3:493-504.
Rajan, S. S. S., K. W. Perrott and W. M. H. Saunders. 1974. Identification
of phosphate-reactive sites of hydrous aluminum from proton consumption
during phosphate adsorption at constant pH values. J. Soil Sci., 25:
438-447.
Richenderfer, J. L., W. E. Sopper and L. T. Kardos. 1975. Spray - irrigation
of treated municipal effluent and its effect on chemical properties of
forest soils. PB-267 808. National Technical Information Service,
Springfield, Virginia.
Robertson, W. K., L. C. Hammond and L. G. Thompson, Jr. 1965. Yield and
nutrient uptake by corn (Zea mays L.) for silage on two soil types as
influenced by fertilizer, plant population and hybrids. Soil Sci. Soc.
Amer. Proc. 29:551-554.
Ruelke, 0. C. and G. M. Prine. 1974. Height and maturity effects on forage
yield and quality of pearl millet and sorghum - sudangrass hybrids. Soil
and Crop Sci. Soc. Fla. Proc. 33:7-9.
Sanks, R. L. and T. Asano. 1976. Land treatment and disposal of municipal
and industrial wastewater. Ann Arbor Science. Ann Arbor, Michigan.
Seabrook, B. L. 1975. Land application of wastewater in Australia. The Wer-
ribee farm system, Melbourne, Victoria. PB-257 454. National Technical
Information Service, Springfield, Virginia.
Shuval, H. I. 1976. Water renovation and reuse. Academic Press, New York.
Slack, L. J. 1975. Hydrologic environmental effect of sprayed sewage efflu-
ent, Tallahassee, Florida. Water Resources Investigations 55-75. U.S.
Geological Survey. Tallahassee, Florida.
Smith, J. M. 1970. Chemical engineering kinetics. 2nd ed. McGraw-Hill Book
Co., New York.
Smith, W. H. and J. 0. Evans. 1977. Special opportunities and problems in
using forest soils for organic waste application. In_; Soils for Manage-
ment of Organic Waste Waters. L, F. Elliot and F. J. Stevenson (eds.)
American Society of Agronomy, Madison, Wisconsin.
184
-------
Smith, W. D., D. M. Post and F. W. Adrian. 1978. Waste recycling in forests.
Presented at 8th World Forestry Conference, October. Jakarta, Indonesia.
Stanley, R. L., Jr. and F. M. Rhoads. 1971. Response of corn grown at low
soil moisture tension to row and drill spacings. Soil and Crop Sci. Soc.
Fla. Proc. 31:41-45.
Stevens, R. M. 1972. Green land - clean streams. Center for the Study of
Federalism. Philadelphia, Pennsylvania.
Sullivan, R. E., M. M. Cohn and S. S. Baxter. 1973. Survey of facilities
using land application of wastewater. EPA-430/9-73-006. U. S. Environ-
mental Protection Agency, Office of Water Programs Operations, Washing-
ton, D.C.
Tandon, H. L. S. and L. T. Kurtz. 1968. Isotopic exchange characteristics of
Aluminum and iron-bound fractions of soil phosphorus. Soil Sci. Soc.
Amer. Proc. 32:799-802.
Tofflemire, T. J. 1977. Land application of wastewater. Jour. Water Poll.
Control Fed., 49:1087-1094.
Ulrich, B., H. Lin and H. Karapurkar. 1962. Kinetics of isotopic exchange
between soil phosphates, soil solution and plant. In: Radioisotopes in
soil-pi ant nutrition studies. International Atomic Energy Agency, Vienna.
U. S. Environmental Protection Agency. 1971. Methods for chemical analysis
of water and wastes. Cincinatti, Ohio.
U. S. Environmental Protection Agency. 1977. Process design manual for land
treatment of municipal wastewater. EPA 625/1-77-008. Office of Water
Program Operations. Washington, D.C.
Vesilind, P- A. 1975. Treatment and disposal of sludges. Ann Arbor Science,
Ann Arbor, Michigan.
Wilkinson, G. N. 1961. Statistical estimation in enzyme kinetics. Biochem.
J., 80:324-332.
Woodhouse, W. W., Jr. 1968. Long term fertility requirements of coastal
bermudagrass. I. Potassium. Agronomy J., 60:508-512.
Young, C. E. 1976. The cost of land application of wastewater: A simulation
analysis. Technical Bulletin No. 1555. Economic Research Service, U.S.
Department of Agriculture, Washington, D.C.
Young, C. E. and G. A. Carlson. 1974. Economic analysis of land treatment of
municipal wastewaters. Report No. 98. Water Resources Research Center,
N. C. State University, Raleigh, North Carolina.
185
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APPENDIX A
RESULTS FOR CROP YIELDS AND NUTRIENT RECOVERY
INTRODUCTION
Detailed results for the various crops and years are presented in this
appendix because of the voluminous amount of data. Results are presented by
years due to commonality of wastewater characteristics and cultural practices.
A summary of results by crops is presented in Section 6 to relate data from
different years. In this report, mton is used to denote metric tons, as
distinguished from English tons, to minimize confusion. For each year the
crop varieties are listed since yields and chemical composition may vary
widely among varieties of the same crop.
1971 SUMMER CROPS
The two crops used were sorghum x sudangrass (Asgrow Grazer-S) and kenaf
(Everglades 41). Following plowing and disking, the plots (30 m x 30 m) were
planted in 0.9 m (3 ft) rows, with a seeding rate of 11 kg/ha (10 Ib/acre).
Planting and harvesting followed the schedule shown in Table A-l. Irrigation
rates were 25, 50, 100 and 200 mm/week. Green weights were measured for each
TABLE A-l. FIELD SCHEDULE FOR SUMMER 1971
Operation
Planting
Crop
Sorghum x sudangrass
4/7/71
Kenaf
4/9/71
Harvesting
1st 6/16/71 6/16/71
2nd 8/25/71 9/27/71
plot by collecting all the vegetation. From each batch 1 kg composite samples
were taken, dried in a forced air oven at 70°C for 24 hr, weighed again and
ground in a Wiley mill. Duplicate 1 g samples were analyzed for Kjeldahl-N
(USEPA, 1971). Other nutrients were measured from 0.5 g samples digested in
15 ml HNO^ and 10 ml HC10*, made up to 50 ml with deionized water. Chemical
analyses included P by SnC^ (APHA, 1971), K and Na by flame emission, and all
others by atomic absorption. Effluent samples were analyzed by the same
methods.
186
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Chemical characteristics of the effluent were measured weekly on compos-
ite samples. Average values for the period 4/71-9/71 are shown in Table 6.
Effluent pH averaged 7.6 while nitrogen composition was 74% Nhty-N, 13% N03-N
and 13% organic N. Since these samples were not analyzed for P, K, Ca, Mg,
and Na, values for the period 4/72-9/72 were used.
Sorghum x Sudangrass
The crop showed positive response to effluent irrigation. Yields of
green forage as well as dry forage showed an increase with application rate,
as shown in Table A-2. Dry matter content remained essentially constant, for
TABLE A-2.
YIELD AND
DRY MATTER
OF SORGHUM
X
SUDANGRASS -
1971
Rate
mm/week
25
50
1
st
100
Harvest
200
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
23.7
21.2
5.04
18.6
21.9
4.08
26.9
18.1
4.86
32.9
18.8
6.18
2nd Harvest
23.7
23.6
5.60
25.3
21.7
5.49
39.9
20.4
8.13
31.4
23.3
7.28
Net
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
42.3
21.5
9.12
50.6
20.7
10.46
58.2
20.0
11 .67
71.3
21.6
15.41
an average composite value of approximately 21%. These results compare
closely with fertility trials in Gainesville, Florida (Agronomy Mimeo Report,
1971) with this same variety where 228 kg/ha of applied N produced 58.8
mtons/ha.
By combining dry yields (Table A-2) and nutrient composition (Table A-3),
crop uptake of the various elements was calculated (Table A-4). Nutrient
uptake of all elements (except Fe and Zn) showed an increase with irrigation
rate. A positive correlation between uptake and application rate of nutrients
may be seen from Table A-4. All of these illustrated the response of dimin-
ishing returns, i.e. succeeding increments of nutrient applied produced
smaller and smaller increments~of uptake. This in turn led to decreasing
efficiency of recovery. Figure A-l illustrates these features for nitrogen.
For example, an irrigation rate of 25 mm/week (1 in./week) provided 88 kg/ha N
187
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TABLE A-3. NUTRIENT COMPOSITION OF SORGHUM X SUDANGRASS - 1971
Rate mm/week
N
P
K
Ca %
Mg
Na
Fe
Zn
N
P
K
Ca %
Mg
Na
Fe
Zn
N
P
K
Ca %
Mg
Na
Fe
Zn
25
0.89
0.42
0.29
0.39
0.53
0.16
0.0091
0.0037
1.04
0.75
0.98
0.50
0.57
0.18
0.0380
0.0041
0.96
0.57
0.60
0.44
0.55
0.18
0.0220
0.0039
50
1st
0.94
0.67
0.43
0.46
0.67
0.21
0.0065
0.0038
2nd
1.14
0.80
1.12
0.50
0.64
0.10
0.0140
0.0053
1 .05
0.74
0.80
0.48
0.65
0.15
0.0105
0.0045
100
Harvest
0.86
0.54
0.26
0.46
0.72
0.12
0.0100
0.0026
Harvest
1.50
1.00
0.96
1.55
0.95
0.36
0.0200
0.0097
Net
1.17
0.67
0.59
0.97
0.83
0.23
0.0147
0.0059
200
1.30
0.76
0.21
0.77
1.01
0.19
0.0390
0.0054
1.20
0.66
0.85
0.58
0.65
0.15
0.0130
0.0042
1.25
0.71
0.51
0.68
0.84
0.17
0.0195
0.0048
188
-------
45
21
15
20
27
9.0
0.46
0.19
46
33
21
22
33
10.2
0.31
0.18
54
33
16
28
44
7.4
0.62
0.16
105
62
17
63
82
15.5
3.17
0.44
TABLE A-4. NUTRIENT UPTAKE BY SORGHUM X SUDANGRASS - 1971
Rate mm/week 25 50 1_00 200
1st Harvest
N
P
K
Ca kg/ha
Mg
Na
Fe
Zn
2nd Harvest
N 43 64 83 87
P 31 45 55 48
K 40 63 53 62
Ca kg/ha 20 28 85 42
Mg 23 36 52 47
Na 7.4 5.6 19.7 11.0
Fe 1.54 0.78 1.10 0.95
Zn 0.17 0.29 0.53 0.30
Total
N
P
K
Ca kg/ha
Mg
Na
Fe 2.00 1.09 1.72 4.12
Zn 0.36 0.47 0.69 0.74
88
52
55
40
50
16.4
110
78
84
50
69
15.8
137
88
69
113
97
27.1
192
no
79
105
129
26.5
189
-------
UD
O
o
N
Figure A-l. Nitrogen recovery by sorghum x sudangrass.
-------
TABLE A-5. NUTRIENT RECOVERY BY SORGHUM X SUDANGRASS - 1971
Rate mm/week 25 50 TOO 200
Harvested, kg/ha
N 88 110 137 192
P 52 78 88 110
K 55 84 69 79
Ca 40 50 113 105
Mg 50 69 97 129
Na 16.4 15.8 27.1 26.5
Applied, kg/ha
N 88 175 350 700
P 42 85 170 340
K 21 42 85 170
Ca 112 225 450 900
Mg 31 62 125 250
Na 122 245 490 980
Recovered, %
N 100 63 39 27
P 120 92 52 32
K 260 200 81 46
Ca 36 22 25 12
Mg 160 110 78 52
Na 13.0 6.4 5.5 2.7
191
-------
with a corresponding uptake of 88 kg/ha N, for a recovery efficiency of 100%,
Increasing the application rate to 50 mm/week (2 in./week) raised the values
to 175 kg/ha N applied, 110 kg/ha harvested and 63% recovery.
From Table A-5 it appears that most elements were supplied in adequate
quantity in the effluent. The major exception to this was K. At 25 mm/week
recovery was 260%. For a soil low in available K, as Lakeland fine sand is,
a deficiency of K could eventually occur. Supplemental K might then be
required. It has been pointed out that effluent is deficient in K for pro-
ducing forage crops (Kardos, et_ al_., 1974).
It should be pointed out that response of a crop to added nutrients
depends upon nutrient reserves in the soil. From this work, Overman and Evans
(1978) estimated soil reserves of N, P and K of 56, 45 and 45 kg/ha, respec-
tively. Such values do not seem unusual, since the plots had carried a grass
cover under irrigation with effluent (no grass removal) for five prior years.
However, under crop harvest, these reserves of N and K would likely diminish.
In normal practice, two or three harvests of sorghum x sudangrass would
be expected. A third harvest failed for lack of weed control.
Kenaf
Yield results are shown in Table A-6. Both green and dry yields
increased with irrigation rate, while dry matter content decreased slightly.
These results agreed closely with fertility trials in Gainesville, Florida
(Pepper and Prine, 1969) with this variety, where 190 kg/ha N applied produced
11 mton/ha of oven dry material.
TABLE A-6. YIELD AND DRY MATTER OF KENAF - 1971
Rate
mm/ week
25
50 100
200
1st Harvest
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
19.7
15.0
2.96
27.8
28.0
7.77
47.5
22.6
10.7
28.4
13.9
3.94
29.6
15.3
4.52
2nd Harvest
30.5
25.6
7.80
Net
58.9
19.9
11.7
30.7
22.6
6.92
60.3
19.0
11.4
39.6
16.9
6.70
40.1
19.2
7.71
79.7
18.1
14.4
192
-------
TABLE A-7. NUTRIENT COMPOSITION OF KENAF - 1971
Rate
N
P
K
Ca
Mg
Na
Fe
Zn
N
P
K
Ca
Mg
Na
Fe
Zn
N
P
K
Ca
Mg
Na
Fe
Zn
mm/ week 25
1.49
0.90
0.28
% 1.91
1.02
0.28
0.0150
0.0049
0.74
0.74
0.86
% 1.38
0.75
0.22
0.0120
0.0076
0.94
0.78
0.70
% 1.52
0.82
0.24
0.0128
0.0069
50
1st
1.46
0.78
0.27
1.60
0.92
0.25
0.0170
0.0044
2nd
0.90
0.80
0.93
1.49
0.85
0.25
0.0140
0.0082
1.09
0.79
0.71
1.53
0.87
0.25
0.0150
0.0069
100
Harvest
1.34
0.86
0.28
1.70
1.02
0.33
0.0150
0.0059
Harvest
1.06
0.88
1 .25
1.40
0.85
0.40
0.0200
0.0094
Net
1.16
0.87
0.96
1.52
0.92
0.37
0.0180
0.0080
200
2.73
0.68
0.24
1.76
0.96
0.24
0.0250
0.0039
2.34
0.62
3.62
2.22
0.82
0.23
0.0340
0.0064
2.52
0.65
2.05
2.01
0,88
0.23
0.0300
0.0052
193
-------
TABLE A-8. NUTRIENT UPTAKE BY KENAF - 1971
Rate
N
P
K
Ca
Mg
Na
Fe
Zn
N
P
K
Ca
Mg
Na
Fe
Zn
N
P
K
Ca
Mg
Na
Fe
Zn
mm/week 25
44
27
8
kg/ha 56
30
8.3
0.45
0.15
57
57
67
kg/ha 107
58
17.1
0.93
0.59
101
84
75
kg/ha 163
88
25.4
1.38
0.74
50
57
31
11
63
36
9.
0.
0.
71
62
72
116
66
19.
1.
0.
128
93
83
179
102
29.
1.
0.
100
1st Harvest
60
39
13
77
46
9 14.9
67 0.67
17 0.27
2nd Harvest
73
61
97
97
59
5 27.7
09 1.39
64 0.65
Total
133
100
no
174
105
4 42.6
73 2.06
81 0.92
200
183
46
16
118
64
16.1
1.68
0.26
180
48
279
171
63
17.7
2.62
0.49
363
94
186
289
127
33.8
4.30
0.75
194
-------
TABLE A-9. NUTRIENT RECOVERY BY KENAF - 1971
Rate mm/week
N
P
K
Ca
Mg
Na
N
P
K
Ca
Mg
Na
N
P
K
Ca
Mg
Na
25
101
84
75
163
88
25.4
106
52
26
138
39
151
95
160
290
120
220
17.0
50
Harvested,
128
93
83
179
102
29.4
Applied,
212
103
52
275
78
302
Recovered
60
90
160
65
130
9.7
100
kg/ha
133
100
110
174
105
42.6
kg/ha
425
206
103
550
157
605
01
, h
31
48
no
32
67
7.0
200
363
94
186
289
127
33.8
850
412
206
1100
314
1210
43
23
140
26
41
2.8
195
-------
IRRIGATION RflTE, HM/WEEK
01
1000
N flPPLI
Figure A-2. Nitrogen recovery By kenaf - 1971
-------
Combination of dry yields (Table A-6) and nutrient composition (Table
A-7) provided estimates of nutrient uptake (Table A-8). Increased application
of all nutrients led to increased uptake. Recovery efficiency (Table A-9,
Fig. A-2) decreased with application rate for all elements measured. As with
sorghum x sudangrass, a K deficiency may occur under extended periods of low
irrigation rates (<50 mm/week). Overman and Evans (1978) estimated soil
reserves of N, P and K of 56, 73 and 56 kg/ha, respectively, which agrees
reasonably well with the values estimated from the sorghum x sudangrass data.
Under continuing harvest, these reserves of N and K would be depleted.
Potential uses for kenaf have been discussed by Killinger (1967, 1969).
1971 WINTER CROPS
Rye (Wrens Abruzzi) and ryegrass (Florida Rust Resistant) were selected
for winter crops. Earlier attempts with oats failed, apparently due to
disease problems. All plots were disked, plowed and disked again. Both crops
were drilled at a rate of 1.7 hl/ha (2 bu/acre) on October 22~ 1971. Plots
were harvested in January 1972, but data was invalid due to malfunction of a
weighing device. Plots were harvested again March 17, 1972. Green weights
were recorded and 0.5 kg composite samples collected and dried at 60°C. All
other procedures were the same as for the summer crops. Crop growth was quite
vigorous.
Effluent values from Table 6 were used for the period 10/71-3/72.
Missing values were approximated as those of 4/72-10/72.
Rye
Results in Table A-10 show that green and dry yields increased with
irrigation rate, while dry matter content decreased, i.e. higher irrigation
TABLE A-10. YIELD AND COMPOSITION OF RYE - 1971
Rate mm/week 6 12 25 50
Green Weight, mtons/ha
Dry
Dry
N
P
K
Ca
Mg
Na
Fe
Zn
Matter, %
Weight, mtons/ha
%
6.97
19.3
1.35
4.21
0.68
2.80
0.52
0.23
0.28
0.110
0.0092
8.11
19.0
1.54
4.61
0.69
2.88
0.49
0.24
0.25
0.067
0.0095
11.8
17.1
2.02
4.62
1.05
2.80
1.15
0.46
1.40
0.020
0.0067
15.3
14.7
2.24
4.79
0.94
3.10
1.02
0.43
0.35
0.032
0.0170
197
-------
produced forage of higher moisture content. Nitrogen content of the rye was
quite high, since it was harvested in the dough stage after seed head forma-
tion, and showed an increase with irrigation rate. Again, the curve of
diminishing returns is well illustrated by this data (Table A-ll). Due to
the low application rates, efficiency of recovery was quite high, where H
recovery exceeded 100% (Fig. A-3) for all rates. The likelihood of K
deficiency is strongly indicated here, since recovery exceeded 100%.
Rate
TABLE A-ll. NUTRIENT RECOVERY BY RYE - 1971
mm/week
12
25
50
N
P
K
Ca
Mg
Na
N
P
K
Ca
Mg
Na
Harvested, kg/ha
57
9
38
7
3,1
3.8
12
6
3
16
5
18
71
11
44
8
3.7
3.8
93
21
57
23
9.3
2.8
Applied, kg/ha
25
12
6
32
9
35
50
24
12
65
18
70
Recovered,
108
21
70
23
9.6
7.8
100
48
24
130
36
140
N
P
K
Ca
Mg
Na
470
150
1200
43
67
21
290
88
730
23
40
11
190
88
470
36
50
4
no
44
290
18
26
5
Ryegrass
Green and dry yields of ryegrass (Table A-12) also showed a positive
response to irrigation, with dry matter content showing a sizable decrease.
At 50 mm/week the forage was very wet (89% water). Also, the N content was
somewhat lower than for rye. In fact, nutrient recovery was lower for rye-
grass (Table A-13) than for rye, in spite of the higher yields. Efficiency
of N recovery decreased rapidly with irrigation rate (Fig. A-4), but remained
quite high.
198
-------
HM/HEEK
cc
I
LU
cr
25 50
N flPPLIED, KG/Hfl
50b
Figure A.-3. Nitrogen recovery by Rye - 1971,
199
-------
TABLE A-12. YIELD AND COMPOSITION OF RYEGRASS - 1971
Rate mm/week
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
N
P
K
Ca %
Mg
Na
Fe
Zn
6
11.8
20.1
2.38
1.97
1.06
3.18
1.10
0.45
0.72
0.028
0.0125
12
10.7
18.5
1.98
2.03
1.00
2.78
1.12
0.44
1.15
0.021
0.0091
25
12.9
16.3
2.11
2.35
0.77
2.82
0.74
0.34
1.28
0.042
0.0158
50
21.0
11.0
2.31
2.75
1.17
2.08
0.95
0.32
1.50
0.015
0.0036
TABLE A-13. NUTRIENT RECOVERY BY RYEGRASS - 1971
Rate mm/week
N
P
K
Ca
Mg
Na
N
P
K
Ca
Mg
Na
N
P
K
Ca
Mg
Na
6
47
25
76
26
10.7
17
12
6
3
16
5
18
380
420
2500
160
230
97
12
Harvested,
40
20
55
22
8.7
23
Applied,
25
12
6
32
9
35
Recovered
160
160
900
68
95
63
25
kg/ha
50
16
59
16
7.2
27
kg/ha
50
24
12
65
18
70
, %
100
67
490
24
39
38
50
64
27
48
22
7.4
35
100
48
24
130
36
140
65
56
200
17
20
24
200
-------
IN3
O
Figure A-4. Nitrogen recovery by ryegrass - 1971,
-------
1972 SUMMER CROPS
Crops included sorghum x sudangrass (Asgrow Grazer-S), kenaf (Everglades
41), corn (McNair 440 V for silage and Pioneer 3369 A for grain), and pearl
millet (Tiflate). All plots were disked, plowed and disked again. Planting,
cultivation and harvests followed the schedule in Table A-14. All crops were
TABLE A-14. FIELD SCHEDULE FOR SUMMER 1972
Crop
Sorghum x sudangrass
Kenaf
Corn Silage
Corn Grain
Pearl Millet
Planting
3/23/72
3/23/72
3/23/72
3/23/72
4/13/72
Cultivation
4/27/72
6/8/72
4/27/72
4/27/72
4/27/72
4/27/72
Harvesting
6/7/72
7/27/72
9/26/72
7/7/72
6/21/72
9/7/72
7/3/72
9/28/72
planted in 0.9 m (3 ft) rows with a length of 30 m (100 ft). Four rows of
pearl millet were planted and harvested, with weights being recorded for the
inner two rows, only. All other plantings contained 14 rows. Seeding rates
were as follows: sorghum x sudangrass - 11 kg/ha, kenaf - 11 kg/ha, corn
silage - 11 kg/ha, corn grain - 17 kg/ha, and pearl millet - 11 kg/ha. Ana-
lytical procedures followed those outlined above for the 1971 summer crops.
Duplicates of each crop (except pearl millet) were planted, and each
irrigation rate was duplicated so that single and split application could be
made to compare crop yields and nutrient uptake under the two methods. Split
applications were made as outlined in Table A-15. Results for these studies
have been discussed elsewhere (Overman, 1975 and Overman, 1978).
Chemical characteristics of the effluent for the period 4/72-9/72 are
shown in Table 6. Irrigation rates were 50, 100, 150 and 200 mm/week.
Sorghum x Sudangrass - Single Applications
Three harvests were made. Yields for the third cutting were lower due
to decreased solar radiation and temperature during this period of the year
(Table A-16). Both green and dry weights increased with irrigation rate,
while dry matter content remained essentially constant. The third harvest
also showed slightly lower nitrogen (protein) content than the other two
202
-------
TABLE A-15. SCHEDULE FOR SPLIT APPLICATIONS*
Rate
mm/week
50
100
150
200
Applications
per week
1
2
3
4
Irrigation
days
Wed.
Tues. , Thurs.
Mon. , Wed. , Fri .
Mon., Tues., Thurs., Fri.
* Each increment included 50 m application.
TABLE A-16. YIELD AND DRY MATTER OF SORGHUM X SUDANGRASS
WITH SINGLE APPLICATIONS - 1972
Rate
mm/week
Green Weight
Dry Matter,
Dry Weight,
Green Weight
Dry Matter,
Dry Weight,
Green Weight
Dry Matter,
Dry Weight,
Green Weight
Dry Matter,
Dry Weight,
, mtons/ha
%
mtons/ha
, mtons/ha
%
mtons/ha
, mtons/ha
of
h
mtons/ha
5
"/
la
ml
mtons/ha
tons/ha
50
27.
16.
4.
28.
19.
5.
5.
25.
1.
61.
18.
11.
8
2
50
7
1
49
3
0
34
8
3
3
100
27
15
4
41
18
7
21
23
4
89
18
16
1st
.3
.7
.30
2nd
.0
.7
.66
3rd
.6
.0
.97
.9
.9
.9
150
Harvest
31.
16.
5.
Harvest
32.
18.
6.
Harvest
25.
25.
6.
Net
88.
19.
17.
1
6
17
7
8
14
1
0
27
9
7
6
200
34
16
5
35
18
6
25
23
6
95
18
18
.3
.0
.49
.6
.4
.56
.8
.5
.05
.7
.9
.1
203
-------
ro
o
o
o
IRRIGATION RfiTE, HM/MEEK
0 SO 100 ISO 2
— I I —
X o
"x.
o
*,
O
to
UJ
oc
CE
0
I
E HflRVESTED
800 1200
N flPPLSEO, KG/Hfi
•I !•
-. Q
UJ
oc
j_o yj
» >
o
yj
O
2000
Figure A-5. Nitrogen recovery by sorghum x sudangrass with single
applications - 1972.
-------
TABLE A-17. NUTRIENT COMPOSITION OF SORGHUM X SUDANGRASS
WITH SINGLE APPLICATIONS - 1972
Rate mm/week 50 100 150 200
1st Harvest
N 1.46 1.91 2.12 1.95
P 0.43 0.44 0.38 0.37
K 1.06 1.15 1.04 0.96
Ca % 0.62 0.61 0.72 0.62
Mg 0.55 0.80 0.76 0.58
Na 0.018 0.020 0.025 0.035
Fe 0.015 0.045 0.064 0.014
2nd Harvest
N 1.90 1.94 1.68 1.71
P 0.44 0.33 0.29 0.32
K 0.78 0.82 0.92 1.00
Ca % 0.60 0.49 0.52 0.64
Mg 0.59 0.64 0.70 0.75
Na 0.030 0.035 0.032 0.035
Fe 0.019 0.023 0.029 0.040
3rd Harvest
N 1.59 1.51 1.52 1.61
P 0.39 0.29 0.28 0.27
K 0.90 0.83 0.80 0.80
Ca % 0.65 0.47 0.47 0.43
Mg 0.49 0.44 0.48 0.52
Na 0.033 0.030 0.030 0.025
Fe 0.020 0.015 0.020 0.036
Net
N 1.69 1.81 1.75 1.75
P 0.42 0.35 0.32 0.32
K 0.91 0.91 0.91 0.92
Ca % 0.61 0.52 0.55 0.56
Mg 0.56 0.63 0.64 0.62
Na 0.026 0.029 0.030 0.032
Fe 0.017 0.026 0.036 0.030
205
-------
TABLE A-18. NUTRIENT UPTAKE BY SORGHUM X SUDANGRASS
HITH SINGLE APPLICATIONS - 1972
Rate mm/week 50 100 1_50 200
1st Harvest
N 66 82 110 108
P 19 19 20 20
K 48 49 54 53
Ca kg/ha 28 26 37 34
Mg 25 35 39 31
Na 0.8 0.8 1.3 1.9
Fe 0.7 1.9 3.4 0.8
2nd Harvest
N 104 149 103 112
P 24 26 18 21
K 42 63 56 66
Ca kg/ha 32 38 31 31
Mg 32 49 43 49
Na 1.7 2.7 2.0 2.4
Fe 1.0 1.8 1.8 2.6
3rd Harvest
N 21 75 95 97
P 6 15 18 17
K 12 41 50 48
Ca kg/ha 9 24 29 26
Mg 7 22 30 31
Na 0.4 1.5 1.9 1.6
Fe 0.2 0.8 1.2 2.1
206
-------
TABLE A-19- NUTRIENT RECOVERY BY SORGHUM X SUDANGRASS
WITH SINGLE APPLICATIONS - 1972
Rate
N
P
K
Ca
Mg
Na
Fe
N
P
K
Ca
Mg
Na
Fe
mm/week 50
191
49
102
69
64
2.9
1.9
450
155
62
410
120
492
6
100
Harvested
306
60
153
88
106
5.0
4.5
Applied,
900
310
125
820
240
985
12
150
, kg/ha
308
56
160
97
112
5.2
6.4
kg/ha
1350
465
187
1230
360
1477
18
200
317
58
167
91
111
5.9
5.5
1800
620
250
1640
480
1970
24
Recovered , %
N
P
K
Ca
Mg
Na
Fe
42
31
130
17
53
0.6
30
34
19
99
11
44
0.5
36
23
12
69
8
31
0.4
34
17
9
54
6
23
0.3
22
207
-------
(Table A-17). Nutrient uptake for all elements increased with irrigation
rate for all harvests (Table A-18). While total nutrient uptake for the
season increased with irrigation rate (Table A-19), efficiency of recovery
decreased for all elements. The trend is illustrated in Figure A-5.
Sorghum x Sudangrass - Split Applications
Green and dry yields increased with irrigation rate for all three
harvests (Table A-20). Dry matter content remained essentially constant.
TABLE A-20. YIELD AND DRY MATTER OF SORGHUM X SUDANGRASS
WITH SPLIT APPLICATIONS - 1972
Rate
mm/week
50 100 150
200
1st Harvest
Green Weight, mtons/ha 21.6 36.5
Dry Matter, % 16.4 16.4
Dry Weight, mtons/ha 3.53 5.96
42.6
14.9
6.34
2nd Harvest
Green Weight, mtons/ha 17.2 25.3
Dry Matter, % 18.6 18.0
Dry Weight, mtons/ha 3.20 4.55
34.
16,
5.58
3rd Harvest
Green Weight, mtons/ha 5.7 14.5
Dry Matter, % 20.5 23.0
Dry Weight, mtons/ha 1.16 3.34
34.3
21.5
7.37
45.7
14.0
6.41
42.8
16.0
6.85
36.5
20.0
7.30
Net
Green Weight, mtons/ha
Dry
Dry
Matter,
Weight,
01
h
mtons/ha
44.
17.
7.
5
8
9
76.4
1
1
8.1
3.8
11
1
1
1
7
9
.3
.3
.3
125
16
20
.0
.5
.6
Nutrient content values (Table A-21) were similar to those obtained for single
applications. Nutrient uptake increased with irrigation rate (Table A-22) for
all elements. Efficiency of recovery decreased with application rate (Table
A-23), and showed similar values for split and single applications. Recover-
ies were relatively low due to the high level of N application (Fig. A-6).
208
-------
TABLE A-21. NUTRIENT COMPOSITION OF SORGHUM X SUDANGRASS
WITH SPLIT APPLICATIONS - 1972
Rate mm/week
N
P
K
Ca %
Mg
Na
Fe
N
P
K
Ca %
Mg
Na
Fe
N
P
K
Ca %
Mg
Na
Fe
N
P
K
Ca
Mg
Na
Fe
50
1.47
0.47
1.15
0.52
0.74
0.030
0.024
1.65
0.57
0.95
0.82
0.74
0.032
0.021
1.64
0.39
1.22
0.71
0.79
0.062
0.022
1.56
0.50
1.08
0.65
0.74
0.035
0.023
100
1st
1.93
0.36
0.98
0.54
0.74
0.040
0.018
2nd
1.92
0.50
0.88
0.66
0.75
0.035
0.033
3rd
1.85
0.43
1.08
0.74
0.74
0.050
0.072
1.91
0.42
0.97
0.63
0.74
0.040
0.036
150
Harvest
1.89
0.45
1.11
0.58
0.84
0.060
0.019
Harvest
2.25
0.34
0.91
0.54
0.64
0.045
0.018
Harvest
1.44
0.29
0.79
0.61
0.42
0.040
0.013
Net
1.82
0.35
0.93
0.58
0.63
0.048
0.017
200
1.70
0.38
1.20
0.52
0.69
0.058
0.017
2.27
0.42
0.96
0.88
0.74
0.035
0.028
1.63
0.29
0.95
0.64
0.49
0.045
0.013
1.86
0.36
1.04
0.69
0.63
0.045
0.019
209
-------
TABLE A-22. NUTRIENT UPTAKE BY SORGHUM X SUDANGRASS
WITH SPLIT APPLICATIONS - 1972
Rate mm/week 50 100 1_50 200
1st Harvest
N 52 115 120 109
P 17 21 28 25
K 40 58 71 77
Ca kg/ha 18 32 37 34
Mg 26 44 54 44
Na 1.1 2.4 3.8 3.7
Fe 0.9 1.1 1.2 1.1
2nd Harvest
N 53 87 125 156
P 18 22 19 29
K 30 40 50 66
Ca kg/ha 26 30 30 60
Mg 24 34 36 50
Na 1.0 1.6 2.5 2.4
Fe 0.7 1.5 1.0 1.9
3rd Harvest
N 19 62 106 119
P 4 15 21 21
K 15 36 58 69
Ca kg/ha 8 25 45 47
Mg 9 25 31 36
Na 0.7 1.7 2.9 3.2
Fe 0.2 2.4 1.0 0.9
210
-------
TABLE A-23 . NUTRIENT RECOVERY BY SORGHUM X SUDANGRASS
WITH SPLIT APPLICATIONS - 1972
Rate
N
P
K
Ca
Mg
Na
Fe
N
P
K
Ca
Mg
Na
Fe
mm/week 50
124
39
85
52
59
2.8
1.8
450
155
62
410
120
492
6
100
Harvested
264
58
134
87
103
5.7
5.0
Applied,
900
310
125
820
240
985
12
150
, kg/ha
351
68
179
112
121
9.2
3.2
kg/ha
1350
465
187
1230
360
1477
18
200
384
75
212
141
130
9.3
3.9
1800
620
250
1640
480
1970
24
Recovered, %
N
P
K
Ca
Mg
Na
Fe
27
25
110
13
48
0.6
29
29
19
87
11
42
0.6
39
26
13
77
9
33
0.6
17
21
12
69
9
27
0.5
16
211
-------
IRRIGfiTION RfiTE, MH/NEEK
rv>
0
eoo 1200 seoo
N APPLIED, KG/Hfl
*
Oi
UJ!
cc
UJ!
Figure A-6. Nitrogen recovery by sorghum x sudangrass
with split applications - 1972.
-------
Kenaf - Single Applications
Only one harvest of kenaf was obtained in 1972; the crop simply failed
to regenerate adequately following the first cutting. Both green and dry
yields increased with irrigation rate (Table A-24), while dry matter content
TABLE A-24. YIELD AND COMPOSITION OF KENAF WITH SINGLE APPLICATIONS .- 1972
Rate mm/week 50 100 150 200
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
N
P
K
Ca %
Mg
Na
Fe
35.4
17.6
6.23
1.38
0.43
0.92
1.14
0.78
0.11
0.140
41.0
16.4
6.72
1.57
0.36
0.39
1.01
0.78
0.13
0.099
40.3
16.8
6.76
1.69
0.40
1.05
1.07
0.80
0.16
0.099
49.7
17.2
8.56
1.99
0.30
0.98
1.06
0.74
0,15
0.040
remained essentially constant. Nitrogen content showed a slight increase
with application rate. Crop uptake of N increased with irrigation rate,
while uptake decreased for Fe and remained essentially unchanged for the
other elements. Nitrogen recovery (Figure A-7) was low due to the single
harvest obtained. Recovery was considerably higher in 1971 when two cuttings
were obtained. Recovery of K was 140% at an irrigation rate of 50 mm/week,
which indicated that the effluent was deficient in K at this rate. Results
from 1971 (Table A-9) showed this same effect. Iron was also slightly
deficient at 50 mm/week, but was adequate at higher rates. Crop uptake of
N increased with irrigation rate (Table A-25), while N recovery showed a
decrease (Figure A-7).
213
-------
TABLE A-25. NUTRIENT RECOVERY BY KENAF WITH SINGLE APPLICATIONS - 1972
Rate mm/week 50 100 150 200
Harvested, kg/ha
N 86 105 114 170
P 27 25 27 20
K 57 26 71 66
Ca 71 68 72 72
Mg 48 53 54 49
Na 6.8 8.7 10.8 10.1
Fe 8.7 6.6 6.6 2.7
Applied, kg/ha
N 235 470 705 940
P 85 170 255 340
K 40 80 120 160
Ca 212 425 637 850
Mg 62 125 187 250
Na 205 510 715 1020
Fe 3.2 6.5 9.7 13.0
Recovered, %
N 37 22 16 18
P 32 15 11 6
K 140 32 58 41
Ca 33 16 11 8
Mg 77 42 29 20
Na 2.7 1.7 1.4 1.0
Fe 270 100 68 21
214
-------
ro
en
0
IRRIGflTION RflTE* MM/MEEK
50 100
Figure A-7. Nitrogen recovery by kenaf with single
applications - 1972.
-------
Kenaf - Split Applications
Green and dry yields showed erratic trends with irrigation rate (Table
A-26). Dry matter content showed a decrease, while N content showed an
increase. Nutrient uptake values were somewhat erratic (Table A-27), but N
showed a slight increase with irrigation rate. Efficiency of recovery
decreased for all elements (Figure A-8). Values of N recovery were similar
for split and single applications.
TABLE A-26. YIELD AND COMPOSITION OF KENAF WITH SPLIT APPLICATIONS - 1972
Rate
mm/week
50
100
150
200
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
N
P
K
Ca %
Mg
Na
Fe
41 .0
17.8
7.30
1.19
0.40
0.78
1.18
0.71
0.15
0.080
39.4
16.7
6.59
1.63
0.36
0.80
1.19
0.65
0.20
0.082
32.3
16.0
5.17
1.73
0.37
0.78
1.15
0.72
0.26
0.080
44.1
15.6
6.90
1.78
0.31
0.92
1.17
0.59
0.27
0.110
216
-------
TABLE A-27 . NUTRIENT RECOVERY BY KENAF WITH SPLIT APPLICATIONS - 1972
Rate
N
P
K
Ca
Mg
Na
Fe
N
P
K
Ca
Mg
Na
Fe
mm/week 50
87
29
57
86
52
11
5.8
235
85
40
212
62
255
3.2
100
Harvested,
108
24
53
78
43
13
5.4
Applied,
470
170
80
425
125
510
6.5
150
kg/ha
90
19
40
59
37
13
4.1
kg/ha
705
255
120
637
187
765
9.7
200
123
21
64
81
40
19
7.6
940
340
160
850
250
1020
13.0
Recovered, %
N
P
K
Ca
Mg
Na
Fe
37
35
140
40
82
4.3
180
23
14
65
18
34
2.6
83
13
8
33
9
20
1.7
43
13
6
40
10
16
1.8
59
217
-------
ro
oo
oO
o
cc
I O
o
*
O
to
GC
o:
O-L
IRRIGATION RfiTE, NH/WEEK
•
s HfiRVESTED
+—s-
200 HOD
N fiPPLl
600
800
200
UJ
sr
,© SiJ
fw >
o
o
• UJ
or
-o
1000
Figure A-8. Nitrogen recovery by kenaf with split
applications - 1972.
-------
Corn Grain - Single Applications
Yields of grain were adjusted to a standard dry matter content of 15.5%,
Yields showed a strong response to irrigation rate (Table A-28). Nitrogen
content also increased, while other elements remained essentially constant.
Nutrient uptake of all elements increased with irrigation rate (Table A-29),
while efficiency of uptake decreased for all elements, including N (Figure
A-9).
TABLE A-28. YIELD AND COMPOSITION OF CORN GRAIN
WITH SINGLE APPLICATIONS - 1972
Rate mm/week
Yield nitons/ha
N
P
K
c/s ^
Mg
Na
50
5.98
1.34
-
0.25
0.42
-
0.15
100
8.78
1.40
-
0.22
0.50
-
0.25
150
9.72
1.42
-
0.23
0.52
-
0.20
200
10.66
1.62
-
0.20
0.51
-
0.22
219
-------
TABLE A-29. NUTRIENT RECOVERY BY CORN GRAIN
WITH SINGLE APPLICATIONS - 1972
Rate
N
P
K
Ca
Mg
Na
N
P
K
Ca
Mg
Na
rrm/week 50
80
-
15
25
-
9
290
102
49
262
78
312
100
Harvested
123
-
19
44
-
22
Applied,
580
204
98
524
157
625
150
, kg/ha
138
-
22
50
-
19
kg/ha
870
306
147
786
235
937
200
173
-
21
54
-
23
1160
408
196
1048
314
1250
Recovered, %
N
P
K
Ca
Mg
Na
28
-
31
9.5
-
2.9
21
-
19
8.4
-
3.5
16
_
15
6.4
-
2.0
15
_
11
5.2
_
1.8
220
-------
o
IRRIGflTIGN RflTE, HH/WEEK
IOC? ISO
rv>
ro
Figure A-9. Nitrogen recovery by corn grain
with single application - 1972.
-------
Corn Grain - Split Applications
Yields of grain showed a strong increase with irrigation rate (Table
A-30) and were similar to those from single applications. Nitrogen content
also increased, while other elements showed a decrease. Uptake of N increased
with irrigation rate (Table A-31), and showed similar values to single appli-
cations. Recovery efficiency of N (Figure A-10) showed a general decline
with application rate.
TABLE A-30. YIELD AND COMPOSITION OF CORN GRAIN
WITH SPLIT APPLICATIONS - 1972
Rate
Yield
N
P
K
Ca
Mg
Na
mm/week 50
mtons/ha 4.52
1.26
_
0.25
% 0 . 74
-
0.35
100
8.72
1.42
_
0.25
0.58
-
0.25
150
10.66
1.48
_
0.25
0.50
-
0.20
200
10.04
1.75
_
0.25
0.43
-
0.15
222
-------
TABLE A-31. NUTRIENT RECOVERY BY CORN GRAIN
WITH SPLIT APPLICATIONS - 1972
Rate
N
P
K
Ca
Mg
Na
N
P
K
Ca
Mg
Na
N
P
K
Ca
Mg
Na
mm/week 50
57
-
11
33
-
16
290
102
49
262
78
312
20
-
22
13
-
5.1
100
Harvested,
124
-
22
50
-
22
Appl led,
580
204
98
524
157
625
Recovered
21
-
22
9.5
-
3.5
150
kg/ha
158
_
27
53
-
21
kg/ha
870
306
147
786
235
937
, %
18
-
18
6.7
-
2.2
200
176
_
25
43
-
15
1160
408
196
1048
314
1250
15
-
13
4.1
-
1.2
223
-------
IRRIGfiTI
5.0
RflTE, MH/NEEK
100 ISO
ro
ro
200
i|00 $00
N flPPLIED, KG/Hfl
Figure A-10. Nitrogen recovery by corn grain
with split applications - 1972.
-------
Corn SHage - Single Applications
Corn was harvested for silage when the grain reached the hard dent
stage, 13 weeks after planting. Green and dry yields increased with irriga-
tion rate (Table A-32), while dry matter content remained essentially con-
stant. Content of N also showed an increasing trend. Uptake of N increased
with application rate (Table A-33), while recovery efficiency decreased
(Figure A-ll).
TABLE A-32. YIELD AND COMPOSITION OF CORN SILAGE
WITH SINGLE APPLICATIONS - 1972
Rate mm/week
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
N
P
K
Ca %
Mg
Na
Fe
50
33.2
18.9
6.27
1.51
0.44
0.90
0.41
0.49
0.040
0.025
100
39.2
17.2
6.74
1.74
0.42
0.95
0.34
0.54
0.045
0.045
150
45.0
18.4
8.29
1.81
0.38
0.68
0.42
0.55
0.110
0.070
200
50.8
18.4
9.36
1.63
0.37
0.80
0,26
0.50
0.038
0.030
225
-------
TABLE A-33. NUTRIENT RECOVERY BY CORN SILAGE
WITH SINGLE APPLICATIONS - 1972
Rate
N
P
K
Ca
Mg
Na
Fe
mm/week 50
95
28
56
26
30
2.5
1.6
100
Harvested,
118
29
64
22
36
3.0
3.0
150
kg/ha
150
31
56
35
46
9.1
5.7
200
152
35
75
25
47
3.6
2.8
Applied, kg/ha
N 200 400 600 800
P 70 140 210 280
K 31 62 93 134
Ca 174 358 532 716
Mg 54 108 162 216
Na 215 430 645 860
Fe 3 6 9 12
Recovered, kg/ha
N 48 29 25 19
P 40 21 15 12
K 170 95 56 56
Ca 14.4 6.2 6.5 3.
Mg 56 33 28 22
Na 1.1 0.7 1.4 0.
Fe 53 50 63 23
226
-------
o
Q
to
UJ
Figure A-ll.
Nitrogen recovery by corn silage
with single applications - 1972.
-------
Corn Silage - Split Applications
Green and dry yields increased with irrigation rate (Table A-34), while
dry matter content showed a slight decrease. Content of N also increased.
Nitrogen uptake increased with application rate (Table A-35), while efficiency
of recovery generally decreased (Figure A-12). Recoveries were similar for
split and single applications. This indicated no advantage to the more fre-
quent irrigations.
TABLE A-34. YIELD AND COMPOSITION OF CORN SILAGE
WITH SPLIT APPLICATIONS - 1972
Rate mm/week
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
N
P
K
Ca %
Mg
Na
Fe
50
20.2
19.0
3.83
1.10
0.46
0.92
0.36
0.56
0.045
0.027
100
39.6
18.0
7.15
1.65
0.44
0.95
0.34
0.43
0.062
0.035
150
44.8
17.4
7.80
1.64
0.45
0.88
0.31
0.49
0.065
0.021
200
45.7
16.8
7.66
1.63
0.44
0.90
0.29
0.45
0.078
0.018
228
-------
TABLE A-35. NUTRIENT RECOVERY BY CORN SILAGE
WITH SPLIT APPLICATIONS - 1972
Rate
N
P
K
Ca
Mg
Na
Fe
mm/ week 50
43
18
35
13
21
1.7
1.0
100
Harvested,
118
32
68
25
30
4.5
2.6
150
kg/ha
128
35
68
25
38
5.0
1.7
200
124
34
69
22
35
5.9
1.3
Applied, kg/ha
N 200 400 600 800
P 70 140 210 280
K 31 62 93 134
Ca 174 358 532 716
Mg 54 108 162 216
Na 215 430 645 860
Fe 3 6 9 12
Recovered, %
N 21 29 21 16
P 26 23 17 12
K 100 100 68 52
Ca 7.5 6.9 4.6 3.1
Mg 40 28 24 16
Na 0.78 1.00 0.78 0.69
Fe 37 46 20 12
229
-------
fNJ
CO
O
IRRIGATION RftTE, HH/WEEK
o
aOO 400 600
N HPPLIEO, KG/Hfi
8C?0
Figure A-12. Nitrogen recovery by corn silage
with split applications - 1972.
-------
Pearl Millet
Plots were harvested two times during the season. Green and dry yields
were somewhat erratic (Table A-36) but tended to remain constant with irriga-
tion rate. Dry matter content showed a decreasing trend. Nitrogen content
increased with irrigation rate (Table A-37). Uptake of N by the crop showed
an increase with application rate (Table A-38), while efficiency of recovery
decreased (Table A-39 and Figure A-13). Results from this experiment have
been reported elsewhere (Overman, 1975).
TABLE A-36. YIELD AND DRY MATTER OF PEARL MILLET - 1972
Rate
mm/week
50
100
150
200
Green Weight, mtons/ha 24.2
Dry Matter, % 15.9
Dry Weight, mtons/ha 3,85
Green Weight, mtons/ha 72.8
Dry Matter, % 19.5
Dry Weight, mtons/ha 14.2
Green Weight, mtons/ha 97
Dry Matter, % 18.6
Dry Weight, mtons/ha 18.1
1st Harvest
46.8
14.1
6.61
47.5
12.5
5.94
2nd Harvest
80.2
17.5
14,0
127
16.3
20.6
64.1
17.5
11.2
Net
112
15.4
17.1
66.8
12,8
8.53
71.9
16.5
11.9
139
14,7
20.4
231
-------
TABLE A-37. NUTRIENT COMPOSITION OF PEARL MILLET - 1972
Rate mm/week 50 TOO 150 200
1st Harvest
N 2.2 2.4 2.8 2.9
P 0.92 1.00 0.88 0.75
K 1.52 1.35 2.32 1.73
Ca 0.48 0.52 0.52 0.48
Mg % 0.43 0.70 0.71 0.76
Na 0.035 0.050 0.090 0.110
Fe 0.105 0.046 0.051 0.031
Zn 0.0055 0.0050 0.0055 0.0048
Cu 0.0020 0.0015 0.0013 0.0010
2nd Harvest
N 1.8 2.3 2.7 2.5
P 0.73 0.70 0.73 0.68
K 1.15 1.42 1.52 1.71
Ca 0.39 0.48 0.53 0.60
Mg % 0.51 0.50 0.53 0.58
Na 0.030 0.070 0.070 0.085
Fe 0.044 0.037 0.038 0.038
Zn 0.0040 0.0040 0.0052 0.0040
Cu 0.0010 0.0010 0.0008 0.0008
Net
N 1.9 2.3 2.7 2.7
P 0.78 0.80 0.78 0.70
K 1.23 1.40 1.80 1.71
Ca 0.41 0.49 0.52 0.55
Mg % 0.50 0.56 0.59 0.65
Na 0.031 0.064 0.077 0.096
Fe 0.057 0.040 0.042 0.035
Zn 0.0043 0.0043 0.0053 0.0043
Cu 0.0012 0.0011 0.0009 0.0009
232
-------
TABLE A-38. NUTRIENT UPTAKE BY PEARL MILLET - 1972
Rate
mm/week
50
100
150
200
P
K
Ca
Mg
Na
Fe
Zn
Cu
P
K
Ca
Mg
Na
Fe
Zn
Cu
P
K
Ca
Mg
Na
Fe
Zn
Cu
kg/ha
kg/ha
kg/ha
85
35
59
18
17
1.3
4.0
0.21
0.077
255
104
164
55
72
4.3
6.3
0.56
0.14
340
139
223
73
89
5.6
10.3
0.77
0.22
1st Harvest
159
66
89
34
46
3.4
3.0
0.34
0.100
2nd
323
98
199
67
70
9.9
5.2
0.56
0.14
482
164
288
101
116
13.3
8.2
0.90
0.24
166
52
138
31
42
5.4
3.0
0.32
0.077
Harvest
302
82
170
59
59
7.8
4.3
0.58
0.08
Total
468
134
308
90
101
9.7
7.3
0.90
0.15
246
64
147
41
65
9.5
2.7
0.40
0.085
297
81
203
71
69
10.1
4.5
0.47
0.09
543
145
350
112
134
14.0
8.2
0.87
0.18
233
-------
TABLE A-39. NUTRIENT RECOVERY BY PEARL MILLET - 1972
Rate mm/week 50 100 150 200
Harvested, kg/ha
N 340 482 468 534
P 139 164 134 145
K 223 288 308 350
Ca 73 101 90 112
Mg 89 116 101 134
Na 5.6 13.3 9.7 14.0
Fe 10.3 8.2 7.3 8.2
Zn 0.77 0.90 0.90 0.87
Cu 0.22 0.24 0.15 0.18
Applied, kg/ha
N 460 920 1380 1840
P 150 300 450 600
K 78 156 234 312
Ca 390 780 1170 1560
Mg 122 245 367 490
Na 500 1000 1500 2000
Fe 5 11 16 22
Zn 1.8 3.6 5.4 7.2
Cu 1.1 2.2 3.3 4.4
Recovered, %
N 74 52 34 30
P 93 54 30 24
K 280 185 130 110
Ca 19 13 8 7
Mg 73 47 27 27
Na 1.1 1.3 0.9 1.0
Fe 185 73 43 32
Zn 43 24 17 12
Cu 20 10 5 4
234
-------
ro
oo
en
I O
X
o
Q
UJ
flC
tfs
IRRIGflTION RflTE, MM/WEEK
1
150 , ZOO
Jimnjm I umil-.ii»»
© s HftBVESTED
LUi
oc
,0 UJ
* >
o
o
UJ
flC
Figure A-13. Nitrogen recovery by pearl millet - 1972.
-------
1972 WINTER CROPS
Rye (Wrens Abruzzl) and ryegrass (Florida Rust Resistant) were utilized
as in 1971. All plots were prepared by disking, plowing and disking. Seeding
rates were 1.7 hl/ha (2 bu/acre) for rye and 23 kg/ha (20 Ib/acre) for rye-
grass. All plots exhibited vigorous growth.
Effluent characteristics for the period 10/72-3/73 are shown in Table 6.
Values for K, Ca, Mg and Na were approximated as those from the period 4/72-
9/72.
Rye was harvested on March 22, 1973, and ryegrass on March 27. No plots
were harvested in January due to unavailability of equipment. At irrigation
rates of 75 and 100 mm/week, both rye and ryegrass showed considerable lodging
due to high wind gusts just prior to harvest. Much of the vegetation in these
plots was inaccessible to the forage harvester.
Forage samples were analyzed as outlined for 1971.
Rye
Green and dry yields declined sharply at the upper irrigation rates due
to lodging. Dry matter content decreased with irrigation rate, while N con-
tent showed an increase (Table A-40). Nutrient uptake (Table A-41) also
reflected the problem of lodging. However, uptake values at 25 and 50 mm/week
were accurate due to negligible lodging and showed the typical upward trend.
Recovery efficiencies (Figure A-14) obtained for the lower rates were more
accurate.
TABLE A-40. YIELD AND COMPOSITION OF RYE - 1972
Rate mm/week 25 50 75 100
Green Weight, mtons/ha
Dry
Dry
N
P
K
Ca
Mg
Na
Fe
Al
Matter, %
Weight, mtons/ha
°i
k
15.5
25.5
3.95
1.84
0.76
2.02
0.52
0.31
0.050
0.021
0.010
19.3
23.6
4.55
1.96
0.84
2.21
0.49
0.35
0.060
0.024
0.010
11.6
22.4
2.60
2.34
0.78
2.50
0.56
0.35
0.063
0.025
0.010
7.6
20.9
1.59
2.56
0.88
2.30
0.56
0.44
0.108
0.031
0.015
236
-------
TABLE A-41. NUTRIENT RECOVERY BY RYE -
1972
Rate
N
P
K
Ca
Mg
Na
Fe
Al
N
P
K
Ca
Mg
Na
N
P
K
Ca
Mg
Na
mm/ week 25
73
30
80
21
12
2.0
0.83
0.40
190
64
30
154
46
188
38
47
270
14
26
1.1
50
Harvested,
89
38
101
22
16
2.7
1.09
0.46
Applied,
380
128
60
308
92
376
Recovered
23
30
170
7
17
0.7
75
kg/ha
61
20
65
15
9
1.6
0.65
0.26
kg/ha
570
192
90
462
138
564
, kg/ha
11
10
72
3
7
0.3
100
41
14
37
9
7
1.7
0.49
0.24
760
256
120
616
184
752
5
6
31
1
4
0.2
237
-------
ro
CjO
CD
IRRIGflTION RflTE, MM/WEEK
o
o-
X
v,
O
e,
O
UJ o.
:LiJ
>
ir
CE
tf*__
<%J
25
5.0
75
© E HflRVESTED
0
200
400
600
@00
N fiPPLlEO, KG/Hfl
1£S
o
"*& X'
4- o
LU!
o
iODD
Figure A-14. Nitrogen recovery by rye - 1972.
-------
Ryegrass
Lodging was also a problem for ryegrass at the higher irrigation rates,
as shown by the green and dry yields (Table A-42). At irrigation rates of
25 and 50 mm/week, N uptake showed an increase (Table A-43), as expected.
Recovery efficiency for N declined (Figure A-15) with application rate.
TABLE A-42. YIELD AND COMPOSITION OF RYEGRASS - 1972
Rate
mm/week
25
50
75
100
Green Weight, mtons/ha
Dry
Dry
N
P
K
Ca
Mg
Na
Fe
Al
Matter, %
Weight, mtons/ha
%
30.4
15.5
4.71
1.93
0.54
1.73
0.56
0.39
0.25
0.032
0.010
32.3
21.9
7.07
2.03
0.60
1.74
0.65
0.40
0.51
0.038
0.010
27.8
14.7
4.09
2.07
0.68
1.70
0.69
0.52
0.84
0.047
0.010
24.2
14.4
3.48
2.67
0.69
1.70
0.59
0.45
1.18
0.041
0.020
239
-------
TABLE A-43. NUTRIENT RECOVERY BY RYEGRASS - 1972
Rate
N
P
K
Ca
Mg
Na
Fe
AT
N
P
K
Ca
Mg
Na
mm/week 25
91
25
81
26
18
12
1.5
0.47
190
64
30
154
46
188
50
Harvested
144
42
123
46
28
36
2.7
0.71
Applied,
380
128
60
308
92
376
75
, kg/ha
85
28
70
28
21
34
1.9
0.41
kg/ha
570
192
90
462
138
564
100
93
24
59
21
16
41
1.4
0.70
760
256
120
616
184
752
Recovered, %
N
P
K
Ca
Mg
Na
48
39
270
17
39
6.4
38
33
200
15
30
9.6
15
15
78
6
15
6.0
12
9
49
3
9
5.5
240
-------
IRRIGRTION
0 25 50
cc
X
Q
yj
t—
to
x a-
75
CD s HRRVESTED
125
.o
LU
•O
Figure A-15. Nitrogen recovery by ryegrass - 1972,
-------
1973 SUMMER CROPS
Crops Included sorghum x sudangrass (Asgrow Gazer-A), kenaf (Everglades
41), pearl millet (Asgrow Star), and corn (Pioneer 3369 A) for silage and for
grain. All plots were disked, plowed and disked again. Planting and har-
vesting followed the schedule of Table A-44. Sorghum x sudangrass plots were
TABLE A-44. FIELD SCHEDULE FOR SUMMER 1973
Crop
Sorghum x sudangrass
Kenaf
Corn Silage
Corn Grain
Pearl Millet
Planting
4/11/73
4/11/73
4/25/73
4/25/73
4/25/73
Cultivation Harvesting
6/22/73 6/21/73
8/30/73 8/29/73
10/24/73
7/11/73 7/10/73
7/10/73
8/30/73
6/21/73
8/29/73
rotovated on June 21, 1973, following the first harvest to control crabgrass.
Corn was planted in 90 cm (36 in.) and 45 cm (18 in.) rows at seeding rates
of 17 kg/ha and 34 kg/ha, respectively. Pearl millet was drilled (broadcast
planted) at 28 kg/ha. Sorghum x sudangrass and kenaf were both planted in
90 cm rows at 11 kg/ha.
Characteristics of the effluent for the period 4/73-9/73 are given in
Table 6.
Sorghum x Sudangrass
Three harvests were obtained. Green and dry yields increased with
irrigation rate (Table A-45), while dry matter content remained essentially
constant. Nitrogen composition was independent of rate (Table A-46). Crop
uptake of various elements increased with irrigation rate (Table A-47), while
efficiency of recovery showed a decreasing trend (Table A-48 and Figure A-16),
242
-------
TABLE A-45. YIELD AND DRY MATTER OF SORGHUM X SUDANGRASS
- 1973
Rate mm/ week
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
100
37.2
17.0
6.32
150
1st Harvest
39.6
16.3
6.47
200
70.6
16.5
11.65
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
23.1
23.0
5.31
10.8
20.3
2.20
71.1
19.5
13.8
2nd Harvest
26.2
24.2
6.34
3rd Harvest
11.2
20.1
2.26
Net
77.0
19.6
15.1
26.2
23.4
6.14
12.3
21.5
2.64
109.1
18.8
20.4
243
-------
TABLE A-46. NUTRIENT
COMPOSITION OF SORGHUM X
SUDANGRASS -
1973
Rate mm/ week
N
P
K
Ca
Mg %
Na
Fe
Zn
Mn
N
P
K
Ca
Mg %
Na
Fe
Zn
Mn
N
P
K
Ca
Mg %
Na
Fe
Zn
Mn
N
P
K
Ca
Mg %
Na
Fe
Zn
Mn
100
1st
1.44
0.40
0.79
0.46
0.48
0.100
0.0085
0.0047
0.00085
2nd
1.13
0.25
0.28
0.38
0.31
0.220
0.0125
0.0063
0.00035
3rd
1.66
0.30
0.37
0.63
0.47
0.240
0.0402
0.0022
0.00050
1.35
0.33
0.53
0.46
0.41
0.17
0.015
0.0049
0.00060
150
Harvest
1.35
0.30
0.75
0.45
0.43
0.130
0.0132
0.0034
0.00050
Harvest
1.09
0.22
0.36
0.40
0.28
0.180
0.0095
0.0046
0.00075
Harvest
1.73
0.26
0.34
0.65
0.43
0.245
0.0322
0.0071
0.00075
Net
1.30
0.26
0.53
0.49
0.37
0.17
0.014
0.0044
0.00064
200
1.40
0.30
0.82
0.43
0.42
0.120
0.0135
0.0040
0.00075
1.18
0.23
0.39
0.35
0.25
0.225
0.0635
0.0175
0.00100
1.78
0.28
0.31
0.69
0.44
0.185
0.0585
0.0043
0.00100
1.38
0.28
0.62
0.44
0.37
0.16
0.034
0.0081
0.00086
244
-------
TABLE A-47. NUTRIENT UPTAKE BY SORGHUM X SUDANGRASS - 1973
Rate mm/week
N
P
K
Ca
Mg kg/ha
Na
Fe
Zn
Mn
N
P
K
Ca
Mg kg/ha
Na
Fe
Zn
Mn
N
P
K
Ca
Mg kg/ha
Na
Fe
Zn
Mn
100
91
25
50
29
30
6.3
0.54
0.30
0.054
60
13
15
20
16
11.6
0.66
0.34
0.019
36
7
8
14
10
5.3
0.88
0.048
0.011
150
1st Harvest
87
19
49
29
28
8.4
0.85
0.22
0.032
2nd Harvest
69
14
23
25
18
11.4
0.60
0.29
0.048
3rd Harvest
39
6
8
19
10
5.5
0.73
0.160
0.017
200
163
35
96
50
49
14.0
1.57
0.47
0.087
72
14
24
22
15
13.8
3.90
1.08
0.061
47
7
8
18
12
4.9
1.55
0.114
0.026
245
-------
TABLE A-4d NUTRIENT RECOVERY BY SORGHUM X SUDANGRASS - 1973
Rate mm/week 100 150 200
Harvested, kg/ha
N 187 195 282
P 45 39 56
K 73 80 128
Ca 63 73 90
Mg 56 56 76
Na 23 25 33
Fe 2.1 2.2 7.0
Zn 0.69 0.67 1.66
Applied, kg/ha
N 670 1000 1340
P 245 370 490
K 195 290 390
Ca 1680 2520 3360
Mg 465 700 930
Na 1455 2180 2910
Fe 29 44 58
Zn 8.7 13.1 17.4
Recovered, %
N 28 20 21
P 18 11 11
K 37 28 33
Ca 3.7 2.9 2.7
Mg 12.0 8.0 8.2
Na 1.6 1.2 1.1
Fe 7.1 5.0 12.0
Zn 7.9 5.1 9.6
246
-------
Figure A-16. Nitrogen recovery by sorghum
x sudangrass - 1973,
-------
Kenaf
As in 1972, the kenaf failed to regenerate after first harvest. Green
and dry yields showed the characteristic increase with irrigation rate (Table
A-49), while dry matter content decreased slightly. Nutrient composition was
slightly erratic. Nitrogen uptake was essentially constant (Table A-50),
while N recovery decreased rapidly with irrigation rate (Figure A-17).
TABLE A-49. YIELD AND COMPOSITION OF KENAF - 1973
Rate
mm/week
100
150
200
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
N
P
K
Ca %
Mg
Na
Fe
Zn
Mn
24.6
18.7
4.61
1.86
0.47
0.71
0.99
0.48
0.142
0.0105
0.0065
0.0015
26.4
17.9
4.73
1.86
0.35
0.65
0.96
0.51
0.114
0.0045
0.0068
0.00085
27.6
17.6
4.84
1.67
0.33
0.77
0.87
0.43
0.109
0.0055
0.0056
0.00085
248
-------
TABLE A-50. NUTRIENT RECOVERY BY KENAF - 1973
Rate mm/week IjOO 150 200
Harvested, kg/ha
N 86 88 81
P 22 17 16
K 33 31 37
Ca 46 45 42
Mg 22 24 21
Na 66 54 53
Fe 4.8 2.1 2.7
Zn 3.0 3.2 2.7
Mn
Applied, kg/ha
N 280 420 560
P 106 159 212
K 64 96 168
Ca 710 1070 1420
Mg 196 294 392
Na 620 930 1240
Fe 12 18 24
Zn 3.68 5.52 7.36
Mn -
Recovered, %
N 31 21 14
P 21 10 8
K 51 32 22
Ca 6.4 4.2 3.0
Mg 11.2 8.2 5.3
Na 10.6 5.8 4.2
Fe 40 12 11
Zn 82 58 37
249
-------
en
O
IRRIGATION RfiTE, HM/I^EEK
o
Ifjf
p
CC
O
0
o-
to
oc
I
o-
o
50 100
200 250
O s
;5TED =
200 100
N flPPLIED,
600
°
&
>?
,0 Q
yj
O
o
-------
Pearl Millet
Two cuttings were obtained. The first harvest was at 8 weeks of age.
Some vegetation could not be harvested from the 200 mm/week plot due to
lodging; the crop should have been harvested at 6 or 7 weeks after planting.
Green and dry yields showed an upward trend with irrigation rate (Table A-51
while dry matter content showed a downward trend. Nitrogen content also
tended upward (Table A-52). Crop uptake of N showed a slight increase of N
with application rate (Table A-53). Efficiency of N recovery decreased in
the typical manner (Table A-54, Figure A-18).
TABLE A-51. YIELD AND DRY MATTER OF PEARL MILLET (GAHI-1) - 1973
Rate
mm/week
50
100
150
200
1st Harvest
Green Weight, mtons/ha 45.2 46.1
Dry Matter, % 14.3 12.6
Dry Weight, mtons/ha 6.47 5.82
53.8
12.1
6.50
2nd Harvest
Green Weight, mtons/ha 19.3 23.5
Dry Matter, % 25.1 25.7
Dry Weight, mtons/ha 4.84 6.03
Green Weight, mtons/ha 64.5 69.6
Dry Matter, % 17.5 17.0
Dry Weight, mtons/ha 11.3 11.8
Net
24.0
23.9
5.71
77.8
15.7
12.2
43.9
12.3
5.40
26.9
23.2
6.23
70.8
16.4
11.6
251
-------
TABLE A-52. NUTRIENT COMPOSITION OF PEARL MILLET (GAHI-1) - 1973
Rate
mm/week
50
TOO
150
200
P
K
Ca
Mg
Na
Fe
Zn
Mn
P
K
Ca
Mg
Na
Fe
Zn
Mn
P
K
Ca
Mg
Na
Fe
Zn
Mn
1st Harvest
1.58
0.81
0.89
0.39
0.63
0.029
0.042
0.027
0.0032
1.62
0.86
1.02
0.43
0.70
0.030
0.028
0.019
0.0031
1.78
0.70
1.00
0.44
0.67
0.031
0.018
0.011
0.0032
1.89
0.60
1.11
0.50
0.70
0.038
0.015
0.008
0.0026
2nd Harvest
1.20
0.75
0.70
0.45
0.53
0.009
0.0115
0.0128
0.0021
1.01
0.67
0.75
0.36
0.54
0.010
0.0045
0.0062
0.0011
1.25
0.63
0.67
0.42
0.60
0.012
0.0058
0.0128
0.0020
1.35
0.54
0.76
0.43
0.63
0.010
0.0042
0.0072
0.0014
Net
1.42
0.78
0.81
0.41
0.59
0.021
0.029
0.021
0.0027
1.30
0.76
0.88
0.40
0.62
0.020
0.016
0.013
0.0021
1.53
0.67
0.85
0.43
0.64
0.022
0.012
0.012
0.0026
1.61
0.57
0.92
0.46
0.66
0.023
0.009
0.008
0.0020
252
-------
TABLE A-53. NUTRIENT UPTAKE BY PEARL MILLET (GAHI-1) - 1973
Rate mm/week 50 HX) 150 200
1st Harvest
N 102 94 115 103
P 52 50 45 32
K 58 60 65 60
Ca 25 25 29 27
Mg kg/ha 41 41 44 38
Na 1.92 1.71 2.02 2.05
Fe 2.73 1.66 1.15 0.80
Zn 1.74 1.12 0.72 0.45
Mn 0.21 0.18 0.21 0.14
2nd Harvest
N 58 61 71 84
P 36 40 36 34
K 34 45 38 47
Ca 22 22 24 27
Mg kg/ha 26 33 34 39
Na 0.44 0.63 0.68 0.65
Fe 0.56 0.27 0.34 0.26
Zn 0.62 0.37 0.73 0.45
Mn 0.10 0.07 0.11 0.09
Total
N 160 155 186 187
P 88 90 81 66
K 92 105 103 107
Ca 47 47 53 54
Mg kg/ha 67 77 78 77
Na 2.36 2.34 2.70 2.70
Fe 3.29 1.93 1.49 1.06
Zn 2.36 1.49 1.45 0.90
Mn 0.31 0.25 0.32 0.23
253
-------
TABLE A-54 • NUTRIENT RECOVERY BY PEARL MILLET (6AHI-1) - 1973
Rate
N
P
K
Ca
Mg
Na
Fe
Zn
mm/ week 50
160
88
92
47
67
2.36
3.29
2.36
100
Harvested,
155
90
105
47
77
2.34
1.93
1.49
150
kg/ha
186
81
103
53
78
2.70
1.49
1.45
200
187
66
107
54
77
2.70
1.06
0.90
Applied, kg/ha
N 175 350 525 700
P 60 120 180 240
K 50 100 150 200
Ca 425 850 1275 1700
Mg 112 224 336 448
Na 365 730 1095 1460
Fe 5 11 16 22
Zn 1.7 3.4 5.1 6.8
Recovered, %
N 91 44 35 27
P 150 75 45 28
K 180 105 69 54
Ca 11.1 5.5 4.2 3.2
Mg 60 34 23 17
Na 0.65 0.32 0.25 0.18
Fe 66 18 9 5
Zn 140 44 28 13
254
-------
cn
RRIGflTION
^—
RflTE, MM/WEEK
I|G gqO
O s HfiRVESTED
200
O
O
•£ «
Lu
tf>
UJ
•o
i L, U f
Figure A-18. Nitrogen recovery by pearl millet - 1973,
-------
Corn Silage - 90 cm Rows
A plant density of approximately 45,000 plants/ha (18,000 plants/acre)
was used. Both green and dry yields increased with irrigation rate (Table
A-55), while dry matter content and N content remained essentially constant.
Uptake of all elements showed an upward trend with application rate (Table
A-56). Recovery efficiency for N decreased downward (Figures A-19) from 44%
at 50 mm/week.
TABLE A-55. YIELD AND COMPOSITION OF CORN SILAGE
IN 90 CM RONS - 1973
Rate mm/week 50 100 150 200
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
N
P
K
Ca %
Mg
Na
Fe
Zn
Mn
23
22.2
5.1
1.22
0.48
0.50
0.22
0.25
0.0160
0.0060
0.0042
0.00120
26
23.5
6.1
1.23
0.37
0.57
0.18
0.23
0.0150
0.0060
0.0045
0.00085
34
24.2
8.2
1.09
0.32
0.52
0.13
0.22
0.0085
0.0023
0.0024
0.00075
35
23.3
8.2
1.14
0.35
0.62
0.18
0.21
0.0170
0.0060
0.0044
0.00085
256
-------
TABLE A-56. NUTRIENT RECOVERY BY CORN SILAGE
IN 90 CM ROWS - 1973
Rate
N
P
K
Ca
Mg
Na
Fe
Zn
Mn
N
P
K
Ca
Mg
Na
Fe
Zn
Mn
mm/week 50
62
24
26
11
13
0.82
0.31
0.21
0.061
140
53
42
355
98
310
6
1.84
-
100
Harvested,
75
23
35
11
14
0.92
0.37
0.27
0.052
Applied,
280
106
84
710
196
620
12
3.68
-
150
kg/ha
89
26
43
11
18
0.70
0.19
0.20
0.062
kg/ha
420
159
126
1060
294
930
18
5.52
-
200
93
29
51
15
17
1.
0.
0.
0.
560
212
168
1420
392
1240
24
7.
39
49
36
070
31
Recovered, %
N
P
K
Ca
Mg
Na
Fe
Zn
Mn
44
45
62
3.1
13
0.26
5.2
11
-
27
22
42
1.5
7.1
0.15
3.1
7.3
-
21
16
34
1.0
6.1
0.08
1 .1
3.6
17
14
30
1.
4.
0.
2.
4.
-
1
3
11
0
9
257
-------
CO
IRRIGfiTIGN
©0, 5,0 IOC
—H———r
cc
o
to
LU
•>
££
cr
0
1 SO 200 250
s HflRVESTED ..
+ i I I
,o
.X*
LU
O
HJ
aoo ^oo eoo
M fiPPLIED, KG/Hfl
Figure A-19. Nitrogen recovery by corn silage
in 90 cm rows - 1973.
-------
Corn Silage - 45 cm Rows
Double planting was used to achieve a plant density of approximately
90,000 plants/ha (36,000 plants/acre). Increased irrigation rates caused
higher green and dry yields (Table A-57), with dry matter content and N con-
tent remaining essentially constant. Crop uptake of all elements increased
with application rate (Table A-58), with efficiency of recovery showing a
decrease for N (Figure A-20).
TABLE A-57. YIELD AND COMPOSITION OF CORN SILAGE
IN 45 CM ROWS - 1973
Rate mm/week
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
N
P
K
Ca %
Mg
Na
Fe
Zn
Mn
50
20.4
19.0
4.0
1.42
0.56
0.62
0.28
0.30
0.0225
0.0162
0.0051
0.0017
100
30.2
19.5
5.7
1.45
0.43
0.64
0.23
0.26
0.0285
0.0132
0.0044
0.0010
150
39.6
20.8
8.2
1.31
0.40
0.54
0.25
0.29
0.0130
0.0058
0.0050
0.0011
200
46.1
19.2
8.9
1.56
0.40
0.67
0.27
0.27
0.0320
0.0120
0.0086
0.0011
259
-------
TABLE A-5& NUTRIENT RECOVERY BY CORN SILAGE
IN 45 CM ROWS - 1973
Rate
N
P
K
Ca
Mg
Na
Fe
Zn
Mn
N
P
K
Ca
Mg
Na
Fe
Zn
Mn
mm/week 50
57
22
25
11
12
0.90
0.65
0.20
0.068
140
53
42
355
98
310
6
1.84
-
100
Harvested,
83
25
36
13
15
1.62
0.75
0.25
0.057
Applied,
280
106
84
710
196
620
12
3.68
-
150
kg/ha
107
33
44
21
24
1.07
0.48
0.41
0.090
kg/ha
420
159
126
1060
294
930
18
5.52
-
200
139
36
60
24
24
2.85
1.07
0.77
0.098
560
212
168
1420
392
1240
24
7.36
-
Recovered, %
N
P
K
Ca
Mg
Na
Fe
Zn
Mn
41
42
60
3.1
12
0.29
11
11
_
30
24
43
1.8
7.7
0.26
6.2
6.8
_
25
21
35
2.0
8.2
0.12
2.7
7.4
_
25
17
36
1.7
6.1
0.23
4.5
10.5
_
260
-------
RRIGflTION RfiTE, MM/WEEK
0Q SO 100 150 200 2SO
UJ
i—
to
yj
>
oc
4-0 o
yj
CC
yj
= oiQBwpejcn
™ n In BI ¥ C 3 I t U
•o
Figure A-20. Nitrogen recovery by corn silage
in 45 cm rows - 1973.
-------
Corn Grain
Corn was planted in 90 cm rows at a density of 45,000 plants/ha. Plots
were harvested 18 weeks after planting. Green and dry weights showed a strong
increase with irrigation rate (Table A-59), while dry matter content remained
essentially constant. Nitrogen content also increased with rate. Calcium
was not determined due to an oversight. Plant uptake of all elements
increased with application rate (Table A-60). Efficiency of recovery of N
showed a slight upward trend (Figure A-21), but was very low for all rates,
TABLE A-59. YIELD AND COMPOSITION OF CORN GRAIN IN 90 CM RONS - 1973
Rate mm/week 50 100 150 200
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
N
P
K
1.68
85.8
1.43
1.32
0.36
0.38
2.91
81.9
2.37
1.50
0.35
0.37
5.38
84.7
4.55
1.46
0.32
0.34
6.83
84.5
5.78
1.63
0.30
0.31
Ca % -
Mg 0.092 0.100 0.108 0.095
Na 0.0010 0.0005 0.0005 0.0015
Fe 0.0085 0.0101 0.0068 0.0145
Zn 0.0028 0.0016 0.0015 0.0014
Mn 0.0001 0.0007 0.0001 0.0001
262
-------
TABLE A-60L NUTRIENT RECOVERY BY CORN GRAIN IN 90 CM ROUS - 1973
Rate
N
P
K
Ca
Mg
Na
Fe
Zn
Mn
N
P
K
Ca
Mg
Na
Fe
Zn
Mn
mm/week 50
19
5.1
5.4
-
1.3
0.014
0.12
0.040
0.001
140
52
32
355
98
300
6
1.8
-
100
Harvested
36
8.3
8.8
-
2.4
0.012
0.24
0.038
0.017
Applied,
280
105
64
710
195
600
12
3.7
-
150
, kg/ha
66
14.6
15.5
_
4.9
0.023
0.31
0.068
0.005
kg/ha
420
157
96
1065
293
900
18
5.5
-
200
94
17.3
17.9
_
5.5
0.087
0.84
0.081
0.006
560
210
168
1420
390
1200
24
7.4
-
Recovered, %
N
P
K
Ca
Mg
Na
Fe
Zn
Mn
14
9.8
17
-
1.3
0.005
2.0
2.2
-
13
7.9
14
-
1.2
0.002
2.0
1.0
-
16
9.3
16
-
1.7
0.003
1.7
1.2
—
17
8.2
11
-
1.4
0.007
3.5
1.1
~
263
-------
ro
CT)
IRRIGATION RftTE, HH/MEEK
uv
o
UJ
I—
4O
yj
£C
0
!__1|L_J4L
200
© s HiBRVESTED
600
o
UJ
o
o
UJ
!3C
-O
800
Figure A-21. Nitrogen recovery by corn grain
in 90 cm rows - 1973.
-------
1973 WINTER CROPS
Rye (Wrens Abruzzi) and ryegrass (Gulf Annual) were seeded at rates of
0.9 hl/ha (1 bu/acre) and 1.3 hl/ha (1.5 bu/acre), respectively, using a
cultipacker seeder. Before planting, all plots were disked, plowed and disked
again. Both crops grew vigorously and provided three cuttings. The schedule
of planting and harvesting as shown Table A-61.
Effluent characteristics for this period are given in Table 6.
TABLE A-61. FIELD SCHEDULE FOR WINTER 1973
Operation
Date
Planting
Harvesting
1st
2nd
3rd
11/7/73
1/17/74
2/13/74
4/4/74
Rye
Yields of green and dry forage showed an increase with irrigation rate
(Table A-62), while dry matter content showed a slight downward trend.
Nitrogen content showed a definite increase with irrigation rate (Table A-63),
while other elements showed much smaller changes. Crop uptake of N showed a
strong upward trend (Table A-64). Nitrogen recovery (Table A-65, Figure A-22)
followed the characteristic decline with application. Uptake of K exceeded
supply at 25 and 50 mm/week (Table A-65). This could lead to deficiency under
prolonged practice.
265
-------
TABLE A-62. YIELD AND DRY MATTER OF RYE - 1973
Rate
mm/week
25
50
75
100
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
5.44
17.8
0.97
1.70
23.3
0.39
9.50
25.2
2.39
16.6
22.6
3.75
1st Harvest
8.02 7.20
13.8 15.8
1.11 1.15
2nd Harvest
2.66 2.87
20.8 20.0
0.56 0.57
3rd Harvest
13.31 13.10
22.0 20.4
2.93 2.67
Net
24.0
19.1
4.60
23.3
18.9
4.39
9.21
16.0
1.47
2.31
19.9
0.46
13.78
20.4
2.81
25.3
18.8
4.74
266
-------
TABLE A-63. NUTRIENT CONTENT OF RYE - 1973
Rate mm/week
N
P
K
Ca
Mg %
Na
Fe
Zn
Mn
Cu
N
P
K
Ca
Mg %
Na
Fe
Zn
Mn
Cu
N
P
K
Ca
Mg %
Na
Fe
Zn
Mn
Cu
25
4.13
0.64
2.20
0.47
0.29
0.021
0.040
0.0010
0.0032
0.0012
3.18
0.52
1.46
0.36
0.26
0.041
0.016
0
0.0030
0.0010
1.77
0.37
1.90
0.24
0.20
0.012
0.020
0
0.00125
0.00075
50
1st Harvest
4.42
0.69
1.46
0.48
0.34
0.026
0.027
0.0022
0.0015
0.0013
2nd Harvest
3.61
0.50
1.51
0.39
0.30
0.024
0.017
0
0.0013
0.0012
3rd Harvest
2.67
0.40
1.60
0.33
0.24
0.009
0.016
0
0.00075
0.00075
75
4.06
0.65
1.80
0.57
0.32
0.018
0.098
0.0000
0.0020
0.0018
4.01
0.51
1.55
0.45
0.31
0.028
0.016
0
0.0010
0.0010
2.41
0.44
1.51
0.40
0.25
0.012
0.010
0
0.00025
0.00075
100
4.42
0.65
1.28
0.54
0.32
0.026
0.092
0.0072
0.0020
0.0020
4.18
0.56
1.57
0.46
0.31
0.021
0.015
0
0.0010
0.0010
2.82
0.46
1.49
0.47
0.28
0.009
0.010
0
0.00050
0.00075
(continued)
267
-------
TABLE A-63 .
( continued)
Rate mm/week 25
50 75 TOO
Net
N 2.53 2.83 3.06 3.54
P 0.45 0.49 0.51 0.53
K 1.93 1.55 1.59 1.43
Ca 0.31 0.38 0.45 0.49
Mg % 0.23 0.27 0.28 0.29
Na 0.017 0.015 0.016 0.015
Fe 0.025 0.019 0.034 0.036
Zn _ 0 - -
Mn 0.0019 0.0010 0.0008 0.0010
Cu 0.0009 0.0009 0.0010 0.0012
268
-------
TABLE A-64. NUTRIENT UPTAKE BY RYE - 1973
Rate mm/week 25 50 75 100
1st Harvest
N 40 50 47 65
P 6.2 7.7 7.5 9.6
K 21 16 21 19
Ca 4.6 5.3 6.6 7.9
Mg kg/ha 2.8 3.8 3.7 4.7
Na 0.20 0.29 0.21 0.38
Fe 0.39 0.30 1.13 1.35
Zn 0.010 0.024 0 0.106
Mn 0.031 0.017 0.023 0.029
Cu 0.012 0.014 0.021 0.029
2nd Harvest
N 12 20 23 19
P 2.0 2.8 2.9 2.6
K 6897
Ca 1.4 2.2 2.6 2.1
Mg kg/ha 1.0 1.7 1.8 1.4
Na 0.16 0.13 0.16 0.10
Fe 0.062 0.095 0.091 0.069
Zn 0000
Mn 0.0117 0.0073 0.0057 0.0046
Cu 0.0039 0.0067 0.0057 0.0046
3rd Harvest
N
P
K
Ca
Mg
Na
Fe
Zn
Mn
Cu
42
9
45
5.7
kg/ha 4.8
0.29
0.48
0
0.030
0.018
78
12
47
9.7
7.0
0.26
0.47
0
0.022
0.022
64
12
40
10.7
6.7
0.32
0.27
0
0.007
0.020
79
13
42
13.2
7.9
0.25
0.28
0
0.014
0.021
'continued'
269
-------
TABLE A-64. (continued)
Rate mm/week 25 50 75 100
Total
N 94 148 134 163
P 17 23 22 25
K 72 71 70 68
Ca 12 17 20 23
Mg kg/ha 8.6 12 12 14
Na 0.65 0.68 0.69 0.73
Fe 0.93 0.87 1.49 1.70
Zn 0.01 0.02 0 0.11
Mn 0.073 0.046 0.036 0.048
Cu 0.034 0.043 0.047 0.055
270
-------
TABLE A-65. NUTRIENT RECOVERY BY RYE - 1973
Rate
N
P
K
Ca
Mg
Na
Fe
Zn
N
P
K
Ca
Mg
Na
Fe
Zn
mm/week 25
94
17
72
12
8.6
0.65
0.93
0.01
160
60
29
170
50
190
2.3
1.0
50
Harvested
148
23
71
17
12
0.68
0.87
0.02
Applied,
320
120
58
340
100
380
4.7
2.1
75
, kg/ha
134
22
70
20
12
0.69
1.49
0
kg/ha
480
180
87
510
150
570
7.0
3.1
100
163
25
68
23
14
0.73
1.70
0.11
640
240
116
680
200
760
9.4
4.2
Recovered , %
N
P
K
Ca
Mg
Na
Fe
Zn
59
28
250
7.1
17
0.34
40
1
46
19
120
5.0
12
0.18
19
1
28
12
80
3.9
8
0.12
21
-
25
10
58
3.4
7
0.10
18
3
271
-------
ho
IRRIGflTIGN RflTE, MM/WEEK
o
o-
o:
X o
o
UJ
OC
CE
= HflRVESTED
200
N fiPPLIED, KG/Hfl
,0
(O
,o
lij
flC
o
<_>
bj
Figure A-22. Nitrogen recovery by rye - 1973.
-------
Ryegrass
Increased irrigation rates produced higher yields of green and dry forage
(Table A-66), with a slight decrease in dry matter content. Nitrogen content
increased strongly with rate (Table A-67), while other elements showed only
moderate changes. Crop uptake of N showed a strong upward trend with appli-
cation rate (Table A-68), while recovery of all elements decreased (Table
A-69). Figure A-23 shows the curve of diminishing returns for N.
TABLE A-66. YIELD AND DRY MATTER OF RYEGRASS 1973
Rate
mm/week
25
50
75
100
Green Weight, mtons/ha 4.2
Dry Matter, % 13.2
Dry Weight, mtons/ha 0.56
Green Weight, mtons/ha 6.9
Dry Matter, % 17.0
Dry Weight, mtons/ha 1.17
Green Weight, mtons/ha 17.2
Dry Matter, % 15.8
Dry Weight, mtons/ha 2.71
Green Weight, mtons/ha 28.3
Dry Matter, % 15.7
Dry Weight, mtons/ha 4.44
1st Harvest
12.4
11.2
1.39
12.5
10.2
1.27
2nd Harvest
8.8
15.9
1.40
9.5
15.3
1.45
3rd Harvest
15,
15,
2.42
37.1
14.0
5.21
Net
20.3
12.6
2.56
42.3
12.5
5.28
12.9
11.4
1.48
9.7
15.0
1.45
21.4
13.8
2.95
44.0
13.4
5.88
273
-------
TABLE A-67. NUTRIENT CONTENT OF RYEGRASS - 1973
Rate mm/week
N
P
K
Ca
Mg %
Na
Fe
Zn
Mn
Cu
N
P
K
Ca
Mg %
Na
Fe
Zn
Mn
Cu
N
P
K
Ca
Mg %
Na
Fe
Zn
Mn
Cu
25
3.83
0.93
1.71
0.45
0.25
1.30
0.028
0
0.0022
0.0022
2.92
0.80
1.25
0.49
0.27
1.23
0.033
0
0.0010
0.0012
2.11
0.67
1.24
0.63
0.26
1.08
0.013
0
0.0020
0.0008
50
1st Harvest
4.13
0.92
1.71
0.41
0.25
1.61
0.024
0
0.0018
0.0018
2nd Harvest
2.88
0.87
1.47
0.41
0.26
1.61
0.023
0
0.0015
0.0013
3rd Harvest
3.09
0.82
1.49
0.46
0.29
1.25
0.014
0
0.0015
0.0012
75
4.04
0.86
1.68
0.48
0.29
1.58
0.019
0
0.0020
0.0020
3.78
0.77
1.49
0.47
0.28
1.75
0.023
0
0.0015
0.0015
3.36
0.72
1.57
0.49
0.26
1.33
0.013
0
0.0015
0.0012
100
4.12
0.80
1.68
0.44
0.25
1.38
0.037
0
0.0020
0.0020
3.47
0.72
1.49
0.47
0.27
1.74
0.036
0
0.0015
0.0015
3.20
0.66
1.38
0.48
0.25
1.41
0.013
0
0.0015
0.0012
(continued)
274
-------
TABLE A-67 . (continued)
Rate mm/week 25 50 75 100
Net
N- 2.55 3.30 3.37 3.49
P 0.74 0.86 0.77 0.71
K 1.30 1.77 1.57 1.48
Ca 0.57 0.43 0.48 0.47
Mg % 0.26 0.27 0.28 0.26
Na 1.15 1.44 1.50 1.48
Fe 0.020 0.019 0.017 0.025
Zn 0000
Mn 0.0017 0.0016 0.0016 0.0016
Cu 0.0011 0.0014 0.0015 0.0015
275
-------
TABLE A-68. NUTRIENT UPTAKE BY RYEGRASS - 1973
Rate mm/week 25 50 75 100
1st Harvest
N 21 57 51 61
P 5.2 13 11 12
K 10 24 21 25
Ca 2.5 5.7 6.1 6.5
Mg kg/ha 1.4 3.5 3.7 3.7
Na 7.3 22 20 20
Fe 0.16 0.33 0.24 0.55
Zn 0000
Mn 0.012 0.025 0.025 0.030
Cu 0.012 0.025 0.025 0.030
2nd Harvest
N 34 40 55 50
P 9.4 12 11 10
K 15 21 22 22
Ca 5.7 5.7 6.8 6.8
Mg kg/ha 3.2 3.6 4.1 3.9
Na 14 22 25 25
Fe 0.39 0.32 0.33 0.52
Zn 0000
Mn 0.012 0.021 0.022 0.022
Cu 0.014 0.018 0.022 0.022
3rd Harvest
N
P
K
Ca
Mg
Na
Fe
Zn
Mn
Cu
57
18
34
17
kg/ha 7.0
29
0.35
0
0.054
0.020
75
20
36
11
7.0
30
0.34
0
0.036
0.029
86
18
40
12
6.7
34
0.33
0
0.038
0.031
94
19
41
14
7.4
42
0.38
0
0.044
0.035
(continued)
276
-------
TABLE A-68. (Continued)
Rate mm/week 25 50 75 100
Total
N 112 172 192 205
P 33 45 40 41
K 59 81 83 88
Ca 25 22 25 27
Mg kg/ha 12 14 15 15
Na 50 74 79 87
Fe 0.90 0.99 0.90 1.45
Zn 0000
Mn 0.078 0.082 0.085 0.096
Cu 0.046 0.082 0.078 0.087
277
-------
TABLE A-69 . NUTRIENT RECOVERY BY RYEGRASS - 1973
Rate
N
P
K
Ca
Mg
Na
Fe
Zn
Mn
Cu
N
P
K
Ca
Mg
Na
Fe
Zn
Mn
Cu
mm/ week 25
112
33
59
25
12
50
0.90
0
0.078
0.046
160
60
29
170
50
190
2.3
1.0
-
-
50
Harvested,
172
45
81
22
14
74
0.99
0
0.082
0.082
Applied,
320
120
58
340
100
380
4.7
2.1
-
-
75
kg/ha
192
40
83
25
15
79
0.90
0
0.085
0.078
kg/ha
480
180
87
510
150
570
7.0
3.1
-
-
100
205
41
88
27
15
87
1.45
0
0.096
0.087
640
240
116
680
200
760
9.4
4.2
-
-
Recovered, %
N
P
K
Ca
Mg
Na
Fe
70
55
205
15
24
26
39
54
38
140
6.5
14
19
21
40
22
95
4.9
10
14
13
32
17
76
4.0
7.5
11
15
278
-------
ro
1RRIGRTIGN RflTE, MH/WEEK
o
o-
CT
I
X
o
Q
UJ
5—
4O
yj
£00
100
O s HflRVESTED
oc
yj
>
o
-
Figure A-23. Nitrogen recovery by ryegrass - 1973,
-------
1974 SUMMER CROPS
Crops included pearl millet (Tiflate and Gahi-1), corn (Pioneer 3369 A )
and coastal bermudagrass. All plots were prepared by disking, plowing, and
disking again. Field operations followed the schedule of Table A-70. Pearl
millet was planted at the rate of 11 kg/ha (10 Ib/acre) with a cultipacker
seeder. Corn was planted in 0.9-m (36-in.) rows at a density of approximately
73,000 plants/ha (29,000 plants/acre). Coastal bermudagrass was sprigged in
August 1973 at the rate of 25 bales/ha (10 bales/acre). Bales of fresh green
coastal bermudagrass were distributed over the plots using a manure spreader
and then cut-in by light disking. Good plot coverage was obtained by June
1974. Some weeds were evident in the first cutting.
Characteristics of the effluent for the period 4/74-9/74 are given in
Table 6.
Pearl Millet - Gahi 1
Three cuttings were obtained for the season. Green and dry yields as
well as dry matter content, were all essentially independent of irrigation
rate (Table A-71). Slight lodging was evident at the first harvest for 200
mm/week indicating that the first harvest should have been at 6 or 7 weeks
after planting. A small amount of forage in this plot was not harvestable.
Nitrogen content showed a small increase with rate (Table A-72). Values of
N uptake (Table A-73) were slightly erratic. Efficiency of N recovery (Figure
A-24) was low due to the high application rates of N. Uptake of K exceeded
application for all rates, indicating a potential for K deficiency. Recovery
of other elements decreased with irrigation rate (Table A-74).
280
-------
TABLE A-70. FIELD SCHEDULE FOR SUMMER 1974
Crop
Planting
Harvesting
Pearl Millet
Gahi-1
Tiflate
Corn Silage
Coastal Bermudagrass
4/10/74
6/12/74
3/27/74
6/5/74
7/31/74
10/16/74
10/16/74
7/3/74
6/5/74
7/3/74
7/31/74
10/16/74
TABLE A-71. YIELD AND DRY MATTER OF PEARL MILLET (GAHI-1) - 1974
Rate
mm/week
100
150
200
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
38.8
13.4
5.20
40.5
19.8
8.02
9.2
26.4
2.44
88.5
17.7
15.7
1st Harvest
36.5
13.6
4.97
2nd Harvest
36.7
19.8
7.28
3rd Harvest
10.0
25.4
2.55
Net
83.2
17.8
14.8
41.2
13.2
5.44
37.6
20.4
86.0
32.0
2.76
87.4
18.2
15.9
281
-------
TABLE A-72L. NUTRIENT CONTENT OF PEARL MILLET (GAHI-1) - 1974
Rate mm/week
N
P
K
Ca
Mg %
Na
Fe
Zn
Al
N
P
K
Ca
Mg %
Na
Fe
Zn
Al
N
P
K
Ca
Mg %
Na
Fe
Zn
Al
TOO
1.74
0.85
1.49
0.52
1.32
0.052
0.016
0.0021
0.0025
1.53
0.52
1.06
0.64
1.09
0.035
0.018
0.0027
0.0050
1.14
0.60
0.95
0.81
0.89
0.025
0.017
0.0028
0.0125
150
1st Harvest
1.71
0.85
1.36
0.50
1.18
0.032
0.021
0.0022
0.0025
2nd Harvest
1.56
0.45
1 .04
0.58
0.91
0.025
0.028
0.0012
0.0025
3rd Harvest
1.67
0.49
1.02
0.88
0.88
0.042
0.015
0.0030
0.0125
200
2.09
0.74
1.28
0.52
1.15
0.172
0.018
0.0026
0.0075
1.63
0.41
1.18
0.61
0.90
0.042
0.016
0.0014
0.0025
1.31
0.50
0.86
0.75
0.43
0.023
0.010
0.0040
0.0075
(continued)
282
-------
TABLE A-72. (continued)
jtete mm/week 100 150 200
Net
N 1.55 1.63 1.73
P 0.64 0.59 0.54
K 1.19 1.14 1.16
Ca 0.63 0.61 0.60
Mg % 1.00 1.00 0.90
Na 0.039 0.030 0.084
Fe 0.017 0.023 0.015
Zn 0.0025 0.0019 0.0023
Al 0.0054 0.0042 0.0050
283
-------
TABLE A-73. NUTRIENT UPTAKE BY PEARL MILLET (GAHI-1) - 1974
Rate mm/week
N
P
K
Ca
Mg kg/ha
Na
Fe
Zn
Al
N
P
K
Ca
Mg kg/ha
Na
Fe
Zn
Al
N
P
K
Ca
Mg kg/ha
Na
Fe
Zn
Al
100
90
44
77
27
69
2.7
0.83
0.11
0.13
123
42
85
51
87
2.8
1.4
0.22
0.40
28
15
23
20
22
0.61
0.41
0.068
0.31
150
1st Harvest
85
42
68
25
59
1.6
1.04
0.11
0.12
2nd Harvest
73
33
76
42
66
1.8
2.0
0.09
0.18
3rd Harvest
43
12
26
22
22
1.07
0.38
0.077
0.32
200
114
40
70
28
63
9.4
0.98
0.14
0.41
125
31
91
47
69
3.2
1.2
0.11
0.19
36
14
24
21
12
0.63
0.28
0.110
0.21
284
-------
TABLE A-73 . (continued)
Rate mm/week 100 150 200
Total
N 241 201 275
P 101 87 85
K 185 170 185
Ca 98 89 96
Mg kg/ha 178 147 144
Na 6.1 4.5 13.2
Fe 2.6 3.4 2.8
Zn 0.40 0.28 0.36
Al 0.84 0.62 0.81
285
-------
TABLE A-74. NUTRIENT RECOVERY BY PEARL MILLET (GAHI-1) - 1974
Rate mm/week
N
P
K
Ca
Mg
Na
N
P
K
Ca
Mg
Na
N
P
K
Ca
Mg
Na
100
241
101
185
98
178
6.1
840
260
85
670
200
770
29
39
220
14.6
89
0.79
150
Harvested, kg/ha
201
87
170
89
147
4.5
Applied, kg/ha
1260
390
128
1000
300
1150
Recovered, %
16
22
130
8.9
49
0.39
200
275
85
185
96
144
13.2
1680
520
170
1340
400
1540
16
16
no
7.2
36
0.86
286
-------
00
O
X
O
IRBIGflTIGN RflTE. HM/HiEEK
o . iso
0 s HftRVESTED
200
•
*
O
I O Lull
<* >
O
Lull
1C
Figure A-24.
Nitrogen recovery by pearl millet
(Gahi-1) - 1974,
-------
Pearl Millet - Tiflate
Only one harvest was obtained, 18 weeks after planting. Plots were
irrigated for only 14 weeks. Yields of green and dry forage increased with
irrigation rate (Table A-75), while dry matter content remained approximately
constant. Nitrogen content showed an increase with rate. Crop uptake of N
showed a strong increase with application rate (Table A-76), while recovery
showed a gradual decline from 37% at 50 mm/week (Figure A-25). Again, K
uptake exceeded application.
TABLE A-75. YIELD AND COMPOSITION OF PEARL MILLET (TIFLATE) - 1974
Rate
mm/week
50
100
150
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
N
P
K
Ca %
Mg
Na
Fe
Zn
Al
34
29
10
3
4
1
0.94
0.55
0.60
0.40
0.45
0.020
0.0105
0.0042
0.0050
53.8
26.8
14.4
1.10
0.26
0.72
0.40
0.44
0.030
0.0112
0.0035
0.0075
60
27
16
1
7
2
5
25
0.42
0.71
0.42
0.45
0.032
0.0162
0.0036
0.0150
288
-------
TABLE A-76. NUTRIENT RECOVERY BY PEARL
MILLET (TIFLATE)
- 1974
Rate
N
P
K
Ca
Mg
Na
Fe
Zn
Al
N
P
K
Ca
Mg
Na
Fe
Zn
Al
N
P
K
Ca
Mg
Na
mm/ week 50
95
56
61
40
45
2.0
1.1
0.42
0.51
260
78
26
200
62
235
-
-
-
37
72
230
20
73
0.85
100
Harvested, kg/ha
158
37
104
58
63
4.3
1.6
0.50
1.1
Applied, kg/ha
520
156
52
400
124
470
-
-
-
Recovered, %
30
24
200
15
50
0.91
150
206
69
117
69
74
5.3
2.7
0.59
2.5
780
234
78
600
186
705
-
-
-
26
29
150
12
40
0.75
289
-------
ro
UD
o
IRRIGfiTI
o
o-
cc
o
o
o
.
o
uj
or
1000
Figure A-25. Nitrogen recovery by pearl millet
(Tiflate) - 1974.
-------
Corn Silage
The corn was harvested at the hard dent stage, 14 weeks after planting.
Green and dry yields showed a strong increase with irrigation rate (Table
A-77), while dry matter content was approximately constant. Nitrogen content
showed a slight increase with rate. A large increase in crop N with appli-
cation rate was obtained (Table A-78), but recoveries of N were low (Figure
A-26) due to the high application rates.
TABLE A-77. YIELD AND COMPOSITION OF CORN SILAGE - 1974
Rate mm/week
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
N
P
K
Ca %
Mg
Na
Fe
Zn
Al
100
20.0
28.0
5.58
1.18
0.37
0.27
0.31
0.27
0.038
0.024
0.0030
0.0050
150
25.2
27.2
6.83
1.29
0.39
0.26
0.36
0.31
0.035
0.015
0.0015
0.0025
200
31.5
30.0
9.43
1.26
0.35
0.26
0.26
0.24
0.035
0.011
0.0010
0.0025
291
-------
TABLE A-78. NUTRIENT RECOVERY BY CORN SILAGE - 1974
Rate mm/week
N
P
K
Ca
Mg
Na
Fe
Zn
Al
N
P
K
Ca
Mg
Na
Fe
Zn
Al
N
P
K
Ca
Mg
Na
100
66
21
15
17
15
2.1
1.3
0.17
0.28
510
155
52
403
123
470
-
_
-
13
14
29
4.2
12
0.45
150
Harvested, kg/ha
88
27
18
25
21
2.4
1.0
0.10
0.17
Applied, kg/ha
765
232
78
604
185
705
_
_
-
Recovered, %
12
12
23
4.1
11
0.34
200
119
33
25
25
23
3.3
1.1
0.094
0.24
1020
310
104
806
246
940
_
_
-
12
11
24
3.1
9
0.35
292
-------
ro
UD
oo
IRRIGATION RATE, HM/NEEK
ce "
X
o
o
o—
^^
* '**•
B—
if)
> s-
icr
x -
z
o-
50 100 i|0 200
• ^
x^^
J£f^
^^^
&^1_
-a i»
0 s HlflRVESTED
II. ! || I Jl 1 1! f ||IM
1 I II 1 II I II 1 II .1
O
ex
*l
BO f"ii
01 UJI
UJI
o
=o y
- z
-o
7SO
Figure A-26. Nitrogen recovery by corn silage - 1974.
-------
Coastal Bermudagrass
This grass responded very well to irrigation with effluent. Some prob-
lem with weeds in the plots was experienced. Four cuttings were obtained
(Table A-79). Yields of green and dry forage increased with irrigation rate,
while dry matter content showed a slight decline. Nitrogen content showed
an increase with rate (Table A-80). Nitrogen levels in the last cutting were
low because of the age of the grass; viz, 11 weeks. Better forage quality
would have been obtained at an earlier age, yielding 5 cuttings instead of 4.
Crop uptake of N showed a general increase with application rate (Tables A-81
and A-82). Recovery efficiency exhibited the trend of diminishing returns
(Figure A-27), from a value of 49% at 50 mm/week.
TABLE A-79. YIELD AND DRY MATTER OF COASTAL BERMUDAGRASS - 1974
Rate
mm/week
50
100
150
200
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
10.3
20.0
2.07
6.3
24.4
1.54
7.5
25.6
1.91
10.9
46.0
5.03
35.0
30.3
10.6
1st Harvest
16.1
16.4
2.63
43.2
25.7
11.1
13.9
19.6
2
8.8
25.4
2.23
3rd Harvest
8.6
25.4
2.19
9.7
42.0
4.05
Net
73
2nd Harvest
12.1
26.4
3.19
9.6
25.2
2.41
4th Harvest
12.4
40.6
5.05
48.0
27.9
13.4
13.1
20.0
2.62
14.4
24.0
3.46
12.3
23.6
2.91
11.8
43.6
5.16
51 .6
27.4
14.2
294
-------
TABLE A-80. NUTRIENT CONTENT OF COASTAL BERMUDAGRASS - 1974
Rate
N
P
K
Ca
Mg
Na
Fe
Zn
Al
N
P
K
Ca
Mg
Na
Fe
Zn
Al
N
P
K
Ca
Mg
Na
Fe
Zn
Al
N
P
K
Ca
Mg
Na
Fe
Zn
Al
mm/week 50
1.95
0.37
1.53
0.88
% 0.33
0.13
0.014
0.0071
0.0050
1.96
0.35
1 .50
0.73
% 0.30
0.070
0.021
0.0030
0.0050
1.59
0.37
1.53
0.56
% 0.30
0.055
0.012
0.0019
0.0025
0.49
0.28
0.78
0.45
% 0.21
0.032
0.0062
0.0018
0.0075
100 1
1st Harvest
2.57
0.37
1.80
0.89
0.33
0.26
0.019
0.0040
0.0050
2nd Harvest
2.79
0.37
1.75
0.66
0.36
0.105
0.011
0.0018
0.0050
3rd Harvest
1.85
0.34
1.60
0.55
0.34
0.062
0.010
0.0010
0.0025
4th Harvest
0.56
0.25
1 .09
0.54
0.27
0.045
0.0112
0.0015
0.0125
50
2.57
0.37
1.73
0.72
0.30
0.20
0.017
0.0043
0.0050
2.43
0.36
1.69
0.58
0.34
0.095
0.014
0.0016
0.0050
2.01
0.32
1.45
0.53
0.34
0.058
0.015
0.0012
0.0100
0.70
0.24
0.89
0.45
0.23
0.040
0.0062
0.0009
0.0075
200
2.82
0.37
0.73
0.81
0.35
0.22
0.016
0.0038
0.0050
2.80
0.40
1.79
0.58
0.34
0.095
0.014
0.0018
0.0050
2.18
0.38
1.66
0.60
0.40
0.058
0.016
0.0016
0.0125
0.90
0.24
1.02
0.50
0.27
0.035
0.0078
0.0015
0.0100
(continued)
295
-------
TABLE A-80. (continued)
Rate mm/week 50 TOO 150 200
Net
N 1.18 1.74 1.73 1.98
P 0.32 0.32 0.31 0.33
K 1.16 1.49 1.35 1.47
Ca 0.59 0.65 0.55 0.60
Mg % 0.26 0.32 0.29 0.41
Na 0.061 0.111 0.089 0.088
Fe 0.011 0.013 0.012 0.013
Zn 0.0030 0.0021 0.0018 0.0020
Al 0.0057 0.0072 0.0082 0.0083
296
-------
TABLE A-81 . NUTRIENT UPTAKE BY COASTAL BERMUDA6RASS - 1974
Rate mm/week 50 TOO 150 200
1st Harvest
N 40 68 70 74
P 7.7 9.7 10.1 9.7
K 32 47 47 45
Ca 18 23 20 21
Mg kg/ha 6.8 8.7 8.2 9.2
Na 2.7 6.8 5.5 5.8
Fe 0.29 0.50 0.46 0.42
Zn 0.15 0.11 0.12 0.10
Al 0.10 0.13 0.14 0.13
2nd Harvest
N 30 62 78 35
P 5.4 8.3 11.5 13.8
K 23 39 54 62
Ca 11 15 19 20
Mg kg/ha 5 8 11 12
Na 1.1 2.3 3.0 3.3
Fe 0.32 0.25 0.45 0.48
Zn 0.050 0.040 0.051 0.062
Al 0.08 0.11 0.16 0.17
3rd Harvest
N 30 41 48 63
P 7.1 7.4 7.7 11.1
K 29 35 35 48
Ca 11 12 13 17
Mg kg/ha 5.7 7.4 8.2 11.6
Na 1.1 1-4 1.4 1.7
Fe 0.23 0.22 0.36 0.47
Zn 0.036 0.022 0.029 0.047
Al 0.05 0.05 0.24 0.36
4th Harvest
N 80 23 35 46
P 14 10 12 12
K 329 44 45 53
Ca 23 22 23 26
Mg kg/ha 11 11 12 14
Na 1.6 1.8 2.0 1.8
Fe 0.31 0.45 0.31 0.40
Zn 0.090 0.061 0.045 0.077
Al 0.38 0.51 0.38 0.52
297
-------
TABLE' A-82. NUTRIENT RECOVERY BY COASTAL BERMUDAGRASS - 1974
Rate mm/week 50 100 150 200
Harvested, kg/ha
N 180 194 231 218
P 34 35 41 47
K 123 165 181 208
Ca 63 72 75 84
Mg 29 35 39 47
Na 6.5 12 12 13
Fe 1.2 1.4 1.6 2.0
Zn 0.33 0.23 0.24 0.28
Al 0.61 0.80 0.92 1.18
Applied, kg/ha
N 365 730 1095 1460
P 112 224 336 448
K 37 74 111 148
Ca 290 580 870 1160
Mg 87 174 261 348
Na 335 670 1005 1340
Fe -
Zn -
Al -
Recovered, %
N 49 27 21 15
P 30 16 12 10
K 330 220 160 140
Ca 22 12 9 7
Mg 33 20 15 4
Na 1.9 1.8 1.2 1.0
298
-------
ho
UD
o
a ^
Q
8—
o-
250
•
XI
yji
© = HIRRVES1ED
Hh
N
Figure A-27. Nitrogen recovery by coastal bermudagrass - 1974,
-------
1974 WINTER CROPS
Rye and ryegrass were seeded at rates of 0.5 hi/ha (1/2 bu/acre) and
0.9 hl/ha (1 bu/acre), respectively, with a cultipacker seeder. Plots were
prepared by disking, plowing and disking again before planting. Two cuttings
of both crops were obtained.
Characteristics of the effluent for the period 10/74-3/75 are given in
Table 6.
Rye
Green and dry yields both increased slightly with irrigation rate (Table
A-83). Dry matter content was approximately constant. More than 80% of the
forage harvested was collected in the second cutting; growth was more vigorous
after the first harvest. Nitrogen content increased with rate (Table A-84).
Nitrogen uptake also showed an increase (Table A-85). Due to the high levels
of application (Table A-86), recovery of N was low. Recovery did follow the
downward trend (Figure A-28) generally observed.
TABLE A-83. YIELD AND DRY MATTER OF RYE - 1974
Rate
mm/week
50
75
100
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, I
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
3.00
16.4
0.49
13.8
19.0
2.61
16.8
18.5
3.1
1st Harvest
2.78
17.5
0.49
2nd Harvest
15.7
19.7
3.10
Net
18.5
19.4
3.6
3.99
16.1
0.64
14.9
18.5
2.75
18.9
17.9
3.4
300
-------
TABLE A-84 . NUTRIENT CONTENT OF RYE - 1974
Rate mm/ week
N
P
K
Ca
Mg %
Na
Fe
Zn
Al
50
3.82
0.70
1.80
0.51
0.27
0.030
0.024
0.0065
0.0100
75
1st Harvest
3.72
0.70
1.96
0.54
0.26
0.025
0.020
0.0030
0.0125
100
4.26
0.67
1.84
0.61
0.27
0.060
0.028
0.0052
0.0275
2nd Harvest
N 2.57 2.62 2.89
P 0.46 0.44 0.45
K 2.00 2.05 2.14
Ca 0.41 0.42 0.49
Mg % 0.23 0.23 0.23
Na 0.040 0.038 0.045
Fe 0.0210 0.0225 0.0188
Zn 0.0034 0.0052 0.0045
Al 0.0050 0.0075 0.0100
Net
N 2.76 2.77 3.15
P 0.50 0.48 0.49
K 1.96 2.04 2.09
Ca 0.42 0.63 0.51
Mg % 0.24 0.23 0.24
Na 0.038 0.036 0.048
Fe 0.0212 0.0222 0.0205
Zn 0.0039 0.0049 0.0036
Al 0.0058 0.0082 0.0133
301
-------
TABLE A-85. NUTRIENT UPTAKE BY RYE - 1974
Rate mm/ week
N
P
K
Ca
Mg kg/ha
Na
Fe
Zn
AT
N
P
K
Ca
Mg kg/ha
Na
Fe
Zn
Al
N
P
K
Ca
Mg kg/ha
Na
Fe
Zn
Al
50
19
3.4
8.8
2.5
1.3
0.15
0.11
0.032
0.049
67
12
52
11
6.0
1.0
0.55
0.089
0.13
86
15
61
14
7.3
1.2
0.66
0.12
0.18
75
1st Harvest
18
3.4
9.6
2.6
1.3
0.12
0.10
0.015
0.061
2nd Harvest
81
14
64
13
7.1
1.2
0.70
0.16
0.23
Total
99
17
74
16
8.4
1.3
0.80
0.18
0.29
100
27
4.3
11.8
3.9
1.7
0.38
0.18
0.033
0.176
79
12
59
13
6.3
1 .2
0.52
0.12
0.28
106
16
63
17
8.0
1.6
0.70
0.15
0.46
302
-------
TABLE A-86. NUTRIENT RECOVERY BY RYE - 1974
Rate mm/week 50 75 100
Harvested, kg/ha
N 86 99 106
P 15 17 16
K 61 74 63
Ca 14 16 17
Mg 7.3 8.4 8.0
Na 1.2 1.3 1.6
Fe 0.66 0.80 0.70
Zn 0.12 0.18 0.15
Al 0.18 0.29 0.46
Applied, kg/ha
N 455 682 910
P 100 150 200
K 45 68 90
Ca 320 480 640
Mg 112 168 224
Na 280 420 560
Fe 2.0 3.0 4.0
Zn 3.6 5.4 7.2
Al -
Recovered, %
N 19 15 12
P 15 11 8
K 140 110 70
Ca 4.4 3.3 2.7
Mg 6.5 5.0 3.6
Na 0.43 0.31 0.29
Fe 33 27 18
Zn 3.3 3.3 2.1
303
-------
OJ
o
©'
Iflr
o
O
O
yj J.
to
> g
cc
oc
IRRIGftTION RfiTE, MM/WEEK
© = HRRVESTED
200
N flPPLIED,
ac
UJ!
o
UJ
Figure A-28. Nitrogen recovery by rye - 1974.
-------
Ry_eg_rass
Green and dry yields were somewhat erratic (Table A-87), and showed no
definite trend. Dry matter content did show an increase with rate. Nitrogen
content (Table A-88) did not show a definite trend. Nitrogen uptake showed a
slight upward trend with application rate (Table A-89), with a corresponding
decrease in N recovery (Figure A-29). Recovery of N was low due to the high
application rates of N (Table A-90).
TABLE A-87. YIELD AND DRY MATTER OF RYE6RASS - 1974
Rate
mm/week
50
75
100
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
6.76
13.6
0.92
19.0
12.8
2.43
25.8
13.0
3.35
1st Harvest
7.66
14.4
1.10
2nd Harvest
26.4
13.4
3.53
Net
34.1
13.6
4.63
7.77
12.0
0.93
18.0
15.2
2.73
25.8
14.2
3.66
305
-------
TABLE A-88. NUTRIENT CONTENT OF RYEGRASS - 1974
Rate mm/week
N
P
K
Ca
Mg %
Na
Fe
Zn
Al
50
3.80
0.85
2.06
0.45
0.24
1.14
0.018
0.0048
0.0050
75
1st Harvest
3.62
0.75
2.00
0.47
0.23
1.00
0.034
0.0055
0.0050
100
4.12
0.84
2.18
0.41
0.24
1.29
0.039
0.0065
0.0125
N
P
K
Ca
Mg
Na
Fe
Zn
Al
2.57
0.58
1.66
0.50
0.24
1.25
0.035
0.0194
0.0125
2nd Harvest
2.56
0.60
1.71
0.50
0.23
1.31
0.071
0.0056
0.0075
3.05
0.58
1 .99
0.50
0.25
1.10
0.026
0.0109
0.0175
Net
P
K
Ca
Mg
Na
Fe
Zn
Al
2.89
0.65
1 .76
0.48
0.24
1.21
0.030
0.0153
0.0103
2.80
0.64
1.78
0.49
0.23
1.24
0.062
0.0056
0.0070
3.32
0.65
2.03
0.48
0.25
1.14
0.030
0.0098
0.0162
306
-------
TABLE A-89. NUTRIENT UPTAKE BY RYEGRASS - 1974
Rate mm/ week
N
P
K
Ca
Mg kg/ha
Na
Fe
Zn
Al
N
P
K
Ca
Mg kg/ha
Na
Fe
Zn
Al
N
P
K
Ca
Mg kg/ha
Na
Fe
Zn
Al
50
35
7.8
19
4.1
2.2
10
0.17
0.044
0.046
62
14
40
12
5.8
30
0.85
0.47
0.30
97
22
59
16
8.0
40
1.0
0.51
0.35
75
1st Harvest
40
8.2
22
5.2
2.5
11
0.37
0.060
0.055
2nd Harvest
90
21
60
18
8.1
46
2.51
0.20
0.26
Total
130
29
82
23
10.6
57
2.9
0.26
0.32
100
38
7.8
20
3.8
2.2
12
0.36
0.060
0.116
83
16
54
14
6.8
30
0.71
0.30
0.48
121
24
74
18
9.0
42
1.1
0.36
0.60
307
-------
TABLE A-90 . NUTRIENT RECOVERY BY RYEGRASS - 1974
Rate mm/week
N
P
K
Ca
Mg
Na
Fe
Zn
Al
N
P
K
Ca
Mg
Na
Fe
Zn
Al
N
P
K
Ca
Mg
Na
Fe
Zn
50
97
22
59
16
8.0
40
1.0
0.51
0.35
455
100
45
320
112
280
2.0
3.6
-
21
22
130
5.0
7.1
14
50
14.2
75
Harvested, kg/ha
130
29
82
23
10.6
57
2.9
0.26
0.32
Applied, kg/ha
682
150
68
480
168
420
3.0
5.4
-
Recovered, %
19
19
120
4.8
6.3
14
97
14.8
100
121
24
74
18
9.0
42
1.1
0.36
0.60
910
200
90
640
224
560
4.0
7.2
-
13
12
82
2.8
4.0
8
28
5.0
308
-------
CO
o
O
U>
J
I
X
o
a—
to
tf>
IRRIGATION RATE, MM/WEEK
-I ? I T-H-
4s-
1?
ESTED
s
8
yji
•..:
flC
N
Figure A-29. Nitrogen recovery by ryegrass - 1974,
-------
1975 SUMMER CROP
For this period only coastal bermudagrass was studied. In the summer of
1973 a 1.35 ha (3.34 acres) strip of coastal bermudagrass was sprigged at the
same time and in the manner as the plots. The strip was irrigated with water
from 4 large guns at an average intensity of 28 mm/hr (1.1 in./hr) for 4 hours
for an irrigation rate of 112 mm/week (4.4 in./week). This area had not been
irrigated previously and thus had less weed infestation than the plots.
All plots and the strip were clipped on April 2, 1975, to remove any early
weeds. Some weeds were evident in the 50 mm/week plot at the first and second
harvests, so these plots were simply clipped without weighing the material.
Plots and strip were harvested by the schedule shown in Table A-91.
Effluent characteristics for the period 4/75-9/75 are given in Table 6.
TABLE A-91. HARVEST SCHEDULE FOR SUMMER 1975
Coastal Bermudagrass
Harvest
1
2
3
4
5
6
4/30/75
6/5/75
6/25/75
8/6/75
9/10/75
-
4/30/75
6/5/75
6/25/75
8/6/75
9/10/75
10/21/75
Total Time, weeks 23 29
Coastal Bermudagrass Plots
The plots were harvested 5 times during the season. Due to light weed
infestation, vegetation from the 50 mm/week was not saved for the first and
second harvests. Thus, values for this rate are somewhat low. With this in
mind, it may be seen that dry yields increased only slightly with irrigation
rate (Table A-92), as did dry matter content. Nitrogen content appeared
somewhat uniform with rate (Table A-93). Nitrogen uptake showed only modest
increase with application rates from 100 to 200 mm/week (Table A-94). The
value of nutrient uptake at 50 mm/week was adjusted by assuming that 40% of
total uptake occurred in the first two cuttings (based on results for the
other irrigation rates). Adjusted values are given in Table A-95. Based on
these values N recovery declined downward from 44% at 50 mm/week (Figure
A-30). At this rate K uptake exceeded application, indicating potential
deficiency in long term operation.
310
-------
JABLE A-92. YIELD AND DRY MATTER OF COASTAL BERMUDAGRASS (PLOTS) - 1975
Rate
mm/week
50
100
150
200
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
Green Weight, mtons/ha
Dry Matter, %
Dry Weight, mtons/ha
6.99
24.0
1.68
5.24
27.6
1.46
3.70
26.5
0.99
15.9
26.0
4.13
1st Harvest
2.97
20.0
0.60
1.43
28.8
0.40
2nd Harvest
9.77 10.7
24.6 30.8
2.40 3.29
3rd Harvest
6.88 5.64
25.0 33.5
1.72 1.88
4th Harvest
7.10 5.44
26.0 33.4
1.84 1.81
5th Harvest
4.61
23.8
1.10
31.3
24.5
7.66
Net
3.38
40.4
1.37
26.6
32.9
8.75
1.95
26.4
0.52
11.2
31.2
3.49
6.27
30.7
1.93
4.84
29.0
1.41
4.84
30.8
1.48
29.1
30.3
8.83
311
-------
TABLE A-93 . NUTRIENT CONTENT OF COASTAL BERMUDAGRASS (PLOTS) - 1975
Rate mm/week 50 100 ^50 200
1st Harvest
N - 3.05 3.04 3.29
P - 0.41 0.31 0.34
K - 1.76 1.50 1.58
Ca % - 1.22 0.72 0.72
Mg - 0.34 0.27 0.26
Na - 0.258 0.092 0.068
Fe - 0.0230 0.0155 0.0100
Zn - 0.0048 0.0033 0.0029
2nd- Harvest
N - 2.45 2.27 2.50
P - 0.31 0.33 0.34
K - 1.45 1.95 1.68
Ca % - 1.04 1.02 1.16
Mg - 0.30 0.23 0.26
Na - 0.118 0.075 0.052
Fe - 0.0100 0.0128 0.0122
Zn - 0.0033 0.0031 0.0027
3rd Harvest
N 2.49 2.09 2.53 2.83
P 0.35 0.40 0.29 0.27
K 1.51 1.65 1.62 li.60
Ca % 0.78 0.88 0.54 0.56
Mg 0.31 0.28 0.26 0.25
Na 0.092 0.108 0.052 0.050
Fe 0.0215 0.0130 0.0108 0.0108
Zn 0.0042 0.0041 0.0026 0.0023
4th Harvest
N
P
K
Ca
Mg
Na
Fe
Zn
1.90
0.40
1.32
% 0.55
0.27
0.032
0.0420
0.0075
2.42
0.34
1.41
0.59
0.30
0.070
0.0125
0.0029
2.25
0.29
1.48
0.54
0.26
0.030
0.0232
0.0054
1.86
0.29
1.58
0.65
0.27
0.062
0.0205
0.0060
(continued)
312
-------
TABLE A-93. (continued)
Rate mm/week 50 100 150 200
5th Harvest
P
K
Ca %
Mg
Na
Fe 0.0235 0.0218 0.0180 0.0280
Zn 0.0037 0.0024 0.0017 0.0033
N
P
K
Ca
Mg
Na
Fe
Zn
2.39
0.42
1.26
0.75
0.32
0.050
3.11
0.31
1.32
0.84
0.32
0.105
3.00
0.25
1.10
0.50
0.27
0.045
3.50
0.30
1.41
0.81
0.31
0.05
Net
2.28
0.38
1.39
0.71
0.30
0.060
0.0300
0.0054
2.49
0.56
2.24
0.89
0.29
0.112
0.0132
0.0034
2.48
0.31
1.61
0.73
0.26
0.056
0.0153
0.0033
2.68
0.32
1.60
0.86
0.27
0.055
0.0165
0.0033
313
-------
TABLE A-94. NUTRIENT UPTAKE BY COASTAL BERMUDAGRASS (PLOTS) - 1975
Rate mm/week 50 100 150 200
1st Harvest
N - 18 12 17
P - 2.5 1.2 1.8
K - 11 6.0 8.2
Ca kg/ha - 7.3 2.9 3.7
Mg - 2.0 1.1 1.4
Na - 1.55 0.37 0.35
Fe - 0.14 0.062 0.052
Zn - 0.029 0.013 0.015
2nd Harvest
N - 59 33 35
P - 7.4 10.9 11.9
K 35 64 59
Ca kg/ha - 25 34 40
Mg - 7.2 7.6 9.1
Na - 2.8 2.5 1.8
Fe - 0.24 0.42 0.43
Zn - 0.079 0.102 0.094
3rd Harvest
N 42 36 48 55
P 5.9 6.9 5.5 5.2
K 25 28 30 31
Ca kg/ha 13 15 10 11
Mg 5.2 4.8 4.9 4.8
Na 1.5 1.9 1.0 1.0
Fe 0.36 0.22 0.20 0.21
Zn 0.071 0.071 0.049 0.044
4th Harvest
N
P
K
Ca
Mg
Na
Fe
Zn
28
5.8
19
kg/ha 8.0
3.9
0.47
0.61
0.11
45
6.3
26
10.9
5.5
1.29
0.23
0.05
41
5.2
27
9.8
4.7
0.54
0.42
0.10
26
4.1
22
9.2
3.8
0.87
0.29
0.08
(continued)
314
-------
TABLE A-94. (continued)
Rate mm/week 50 TOO 150 200
5th Harvest
N 24 34 41 52
P 4.2 3.4 3.4 4.4
K 12 15 15 21
Ca kg/ha 7.4 9.2 6.9 12.0
Mg 3.2 3.5 3.7 4.6
Na 0.50 1.16 0.61 0.77
Fe 0.23 0.24 0.25 0.41
Zn 0.037 0.026 0.023 0.049
Total
N 94 192 175 185
P 16 27 26 27
K 56 115 142 141
Ca kg/ha 28 67 64 76
Mg 12 23 22 24
Na 2.5 11.3 5.0 4.8
Fe 1.2 2.3 1.4 1.4
Zn 0^22 o!l8 0.28 0.28
315
-------
TABLE
Rate
N
P
K
Ca
Mg
Na
Fe
Zn
N
P
K
Ca
Mg
Na
Fe
Zn
A-95. NUTRIENT RECOVERY BY COASTAL BERMUDAGRASS (PLOTS)
rim/week 50
155
26
95
48
20
4.1
2.0
0.37
350
105
67
320
no
380
4.5
2.1
100
Harvested,
192
27
115
67
23
11.3
2.3
0.18
Applied,
700
210
134
640
220
760
9.0
4.2
150
kg/ha*
175
26
142
64
22
5.0
1.4
0.28
kg/ha
1050
315
201
960
330
1140
13.5
6.3
- 1975
200
185
27
141
76
24
4.8
1.4
0.28
1400
420
268
1280
440
1520
18.0
8.4
Recovered, %
N
P
K
Ca
Mg
Na
Fe
Zn
44
25
140
15
18
1.1
44
18
27
13
86
10
10
1.5
26
4.3
17
8.3
71
6.7
6.7
0.4
10
4.4
13
6.4
53
5.9
5.5
0.3
8
3.3
*Value at 50 mm adjusted for 1st two harvests.
316
-------
IRRIGATION RfiTE, HH/NEEK
an
cc
X o
0 ^
m
*
O
s Sr
11"™ f^J
CO
yj
X 0-
BS
SO 1 00 1 SO 200 250
1 I 1 1
0 STRIP
m KB
B ^
\
0-^N^^^
\^ PLOTS
m ^^""'v. ^
G = HRRVESTED
IL. — 8 II » II 6 II j II
O
CO
•
m «i ^t_8]
. Qi
LLJl
01
.0 UJ
3F Sl*ii,
•" .^•"
0'
o
= 1 p II
tJiJi
li;
100
800
1200
iOOO
Figure A-30. Nitrogen recovery by coastal bermudagrass - 1975,
-------
Coastal Bermuda Strip
Six cuttings were obtained. Yield of oven dried forage was 15.2 mton/
ha, with an average dry matter content in the field of 28.4% (Table A-96).
Nitrogen content averaged 2.36%. Nutrient uptake values for the various
cuttings are given in Table A-97. Recovery efficiencies for all elements are
given in Table A-98. The value for N was low due to the high application rate
of 1000 kg/ha (890 lb/acre). Even at this high irrigation rate, K uptake
slightly exceeded application. Other elements appeared quite adequate.
TABLE A-96. YIELD AND COMPOSITION OF COASTAL BERMJDAGRASS (STRIP) - 1975
Harvest
Green Weight,
mtons/ha
Dry Matter, %
Dry Weight,
mtons/ha
N
P
K
Ca
Mg
Na
Fe
Zn
1
2.2
28.8
0.63
2.49
0.32
1 .54
0.57
0.25
0.062
0.0190
0.0046
2
13.4
27.9
3.71
2.49
0.35
1.56
0.59
0.28
0.089
0.0035
0.0054
3
8.8
27.4
2.42
2.58
0.33
1.53
0.62
0.30
0.079
0.0198
0.0058
4
13.0
28.5
3.72
1.83
0.30
1.24
0.48
0.28
0.040
0.0097
0.0046
5
10.0
27.5
2.76
2.80
0.30
1.27
0.51
0.29
0.062
0.0149
0.0031
6
6.3
31.7
1.99
2.12
0.31
1.31
0.55
0.30
0.050
0.0206
0.0025
Net
53.7
28.4
15.2
2.36
0.32
1.39
0.55
0.29
0.065
0.0263
0.0044
318
-------
TABLE A-97. NUTRIENT UPTAKE BY COASTAL BERMUDAGRASS (STRIP) - 1975
Harvest
1
2
3
4
5
6
Total
Harvested, kg/ha
N
P
K
Ca
Mg
Na
Fe
Zn
16
2.0
10
3.6
1.6
0.39
0.12
0.029
93
12.9
58
22
10.5
3.3
2.21
0.20
62
8.1
37
15
7.3
1.9
0.48
0.14
67
11.2
46
18
10.3
1.5
0.36
0.17
77
8.4
35
14
8.0
1.7
0.41
0.085
43
6.2
26
11
6.0
1.0
0.41
0.050
357
49
212
84
44
9.9
4.0
0.67
TABLE A-98. NUTRIENT RECOVERY BY COASTAL BERMUDAGRASS (STRIP) - 1975
Element
N
P
K
Ca
Mg
Na
Fe
Zn
Harvested
kg/ha
357
49
212
84
44
9.9
4.0
0.67
Applied
kg/ha
1000
300
190
910
310
1090
12.5
5.9
Recovered
%
35
16
110
9.2
14
0.91
32
11
319
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/2-79-151
4. TITLE AND SUBTITLE
WASTEWATER IRRIGATION AT TALLAHASSEE, FLORIDA
5. REPORT DATE
August 1979 issuing date_
6. PERFORMING ORGANIZATION CODE
3. RECIPIENT'S ACCESSI ON-NO.
7. AUTHOR(S)
Allen R. Overman
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
University of Florida
Agricultural Engineering Department
Gainesville, Florida 32611
10. PROGRAM ELEMENT NO.
1BC822
11. CONTRACT/GRANT NO.
S800829
12. SPONSORING AGENCY NAME AND ADDRESS
Robert S. Kerr Environmental Research Lab-Ada, OK
Office of Research and Development
U.S. Environmental Protection Agency
Ada, Oklahoma 74820
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
EPA-600/15
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Municipal wastewater from the City of Tallahassee, Florida, which has received
secondary treatment was used to demonstrate the effectiveness of wastewater
renovation without pollution of groundwater or surface water through land
application to forage crops by sprinkler irrigation. Five summer and two winter
forage crops were grown with applied wastewater at rates up to 200 and 100 mm per
week, respectively. Vegetation was harvested at appropriate stages of growth and
evaluated for yield response, forage quality, and nutrient removal. Groundwater
chemical characteristics were measured in wells located in the irrigated fields
and compared with off-site control wells and the applied wastewater. Soil samples
were collected from several plots at various depths through time to characterize
the change in soil properties in relation to chemical processes and crop
production.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Land use/water quality
Sewage treatment/winter reclamation
Groundwater/soi1 water
Environmental engineering/waste disposal
Land treatment/sewage
effluents
Land pollution abatement
Land management/crop
management
Wastewater spray irrigat
on
68D
68C
48B
48G
48E
91A
3. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (This Report)
UNCLASSIFIED
21. NO. OF PAGES
340
20. SECURITY CLASS (This page)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (9-73)
320
4 U-S. GOVERNMENT PRINTING OFFICE. 1979-657-060/5387
------- |