Environmental Protection Technology Series
DETERMINATION OF KINETICS OF PHOSPHORUS
MINERALIZATION IN SOILS UNDER
OXIDIZING CONDITIONS
Robert S. Kerr Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Ada, Oklahoma 74820
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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-
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The nine series are:
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This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
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This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-77-180
August 1977
DETERMINATION OF KINETICS OF PHOSPHORUS MINERALIZATION
IN SOILS UNDER OXIDIZING CONDITIONS
by
Y. V. Subbarao
Roscoe Ellis, Jr.
Department of Agronomy
Kansas State University
Manhattan, Kansas 66506
Grant No. R803936
Project Officer
Carl G. Enfield
Wastewater Management Branch
Robert S. Kerr Environmental Research Laboratory
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.
ii
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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) investigate the nature, transport, fate and management of pollutants
in groundwater; (b) develop and demonstrate methods for treating waste-
waters with soil and other natural systems; (c) develop and demonstrate
pollution control technologies for irrigation return flows; (d) develop
and demonstrate 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
iii
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ABSTRACT
In search of a better approach to predict phosphorus movement in soils
from applied wastewaters, reactions of added orthophosphates were studied
in 9 different soils with widely varying physical and chemical properties.
Information obtained on the nature and rate of P reaction will be coupled
with P adsorption data to derive mathematical models for P movement in soils
from applied wastewaters.
Compounds having higher solubility than variscite were formed which
changed to crystalline variscite with time upon adding CaCHaPOOz'HiO to
acid soils. Monocalcium phosphate monohydrate in alkaline soils transformed
to relatively insoluble CaHPOil»2H20, CaSPO^, Ca3(POif)2, CailH(POif)3'2JsH20,
and Cam (OH) 2(1*006. The rate of transformation in both acid as well as
alkaline soils was P rate dependent; slower with increased P rates.
iv
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CONTENTS
Foreword .............................. ±±±
Abstract .............................. iv
Figures ............................... vi
Tables ............................... vii
Abbreviations and Symbols ...................... viii
1. Introduction ......................... 1
2. Conclusions ......................... 3
3. Recommendations ....................... 4
4. Methods and Materials .................... 5
5. Results and Discussion .................... 10
6. References .......................... 21
Appendices
1. Fraction of total P as HsPOit, HaPO^1, HPO^2, PO^3
at various pH values .................... 23
2. Solubility data obtained from adding 100, 40, 25,
and 12.5 ppm P (soil basis) to acid soils ......... 28
3. Solubility data obtained from adding 100, 40, 25,
and 12.5 ppm P (soil basis) to alkaline soils E,
0, and AB ......................... 47
4. Solubility data obtained from adding 100, 40, 25,
and 12.5 ppm P (soil basis) to neutral soil -AC ...... 59
5. Reaction products of applied CaO^POi^'HzO as
identified by X-ray diffraction analysis .......... 63
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FIGURES
Number Page
1. Solubility diagram for variscite and gibbsite
in soils at 25°C 8
2. Solubility diagram for calcium phosphate compounds
in soils at 25°C 8
3. Effect of phosphate addition on the aluminum and
phosphoric acid potentials in soil - B 12
4. Effect of phosphate addition on the aluminum and
phosphoric acid'potentials in soil-D 13
5. Changes in lime and phosphate potentials in soil - E
by adding 100, 40, 25, and 12.5 ppm P 15
6. Changes in lime and phosphate potentials in soil - 0
by adding 100, 40, 25, and 12.5 ppm P 16
7. Changes in lime and phosphate potentials in soil - AB
by adding 100, 40, 25, and 12.5 ppm P 17
8. Changes in lime and phosphate potentials in soil-AC
by adding 100, 40, 25, and 12.5 ppm P 18
vi
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TABLES
Number Page
1. Clay mineralogy of the soils used in this
investigation 5
2. Calculated ion activity products (-log ZAP)
of gibbsite in the acid soils
3. Reported solubility product constants (pK )
at 25°C
4. pH, P, Ca, Mg, Al and ion activity products
(-log IAP values) of variscite measured in
0.01 M CaCl2 extracts of five untreated acid
soils 10
5. Solubility data for three untreated alkaline soils
and one neutral soil 11
vii
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LIST OF ABBREVIATIONS AND SYMBOLS
ABBREVIATIONS
MCPM
DCPD
DCPA
TCP
OCP
HA
G
V
ppm
Monocalcium phosphate monohydrate. [Ca(H.PO,) _'H_0]
Dicalcium phosphate dihydrate. [CaHPO, -2H20]
Dicalcium phosphate anhydrous. [CaHPO,3
Tricalcium phosphate. [Ca_(PO,) ]
Octacalcium phosphate. [Ca,H(PO,)3»2%H20]
Hydroxyapatite. [Ca1
Gibbsite. [A1(OH>3]
Variscite.
parts per million
SYMBOLS
P
Ca+2
Al+3
pH - l/3pAl
pH-
Phosphorus
Calcium
Magnesium
Aluminum
Aluminum hydroxide potential
Lime potential
Phosphate potential
Phosphoric acid potential
viii
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SECTION 1
INTRODUCTION
Large volumes of liquid and solid industrial and municipal wastes result-
ing from increased urbanization and industrialization pose serious disposal
problems. Land as a disposal medium is receiving widespread attention. Soil
can be used as a biological and chemical filter for upgrading the wastewater
prior to discharge; and, if transportation is not limiting, the wastes can be
disposed onto agricultural lands. A major concern in land disposal is the
accumulation in soils of certain metals in toxic quantities and movement of
unacceptable levels of certain other elements such as phosphorus and nitrogen.
Excess phosphorus (P) entering lake waters increases algal bloom and
eutrophication. Naturally occurring ground waters are generally in equili-
brium with hydroxyapatite and hence have a P content less than the acceptable
level of 0.05 ppm. Since phosphorus moves slowly in soils, its role in under-
ground water contamination is generally ignored. However, there are instances
where liberal amounts of P applied to some soils moved substantially deeper
into soil profiles to cause underground water contamination. Adriano et al.
(1) showed clear evidence of perched and underground water contamination by
P from applying large amounts of food processing waste waters for prolonged
periods. According to Fiskell and Spencer (2), P added at very high rates to
a Lakeland fine sand moved as deep as 11 feet. Phosphorus contamination of
high perched water tables from septic tank systems was reported by Reneau and
Pettry (3). Lund et al. (4) analyzed soil cores at various depths beneath
sewage sludge and effluent ponds at two treatment plant locations in
California. Their data suggest that the practice of ponding liquid sewage
sludge and effluent on open, porous soils can result in P contamination of
underground water. They also noticed that agricultural cropland irrigated
with sewage effluent for 7 years was enriched in P to a depth of at least 2
meters. From these studies it appears that unloading large volumes of wastes
without knowing the physical and chemical characteristics of soils in the
disposal sites can lead to P contamination of underground water.
Phosphorus in soils is immobilized by adsorption and chemical precipita-
tion. Precipitation involves transformation of applied soluble phosphates to
relatively insoluble iron, aluminum and calcium phosphates. These insoluble
compounds govern the P concentration in soil solution. Efforts so far have
used P adsorption capacity of soils in predicting P movement. Using the
adsorption data, coupled with the solubility information for the crystalline
compounds formed, to predict P movement can be a better approach than pre-
dicting from P adsorption characteristics alone.
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This study was initiated to obtain information on the nature and rate of
applied orthophosphate transformations for 9 soils differing widely in physi-
cal and chemical characteristics.
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SECTION 2
CONCLUSIONS
Amorphous A1(OH)3 or crystalline gibbsite controlled Al 3 solubility in
acid soils.
Phosphorus fixation was related to pH and clay content of the soils.
Soils with more clay fixed more phosphorus. Acid soils in general had
more P fixation capacity than alkaline soils.
Monocalcium phosphate monohydrate in acid soils transformed to compounds
having higher solubility than variscite (AlPOij • 2H20) which with time
changed to crystalline variscite.
Several calcium phosphate compounds CaHPOit • 2HaO , CaHPOif,
Cai»H(POit)3'2JsH20 and Caio (OH) 2 (POO 6 controlled P solubility when
was added to neutral and alkaline soils.
Phosphorus when applied at higher rates approximating that found near
a fertilizer granule site saturated the soil zone with CaHPOi('2H20 and
CaHPOi» in the acid as well as alkaline soils.
The rate at which the initial and intermediary reaction products formed
and transformed was P rate dependent. The conversion of intermediary
compounds to crystalline variscite was relatively fast at low P rates in
acid soils. Similarly in alkaline soils CaHPOif«2H20 formed initially
converted faster to other compounds at low P rates.
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SECTION 3
RECOMMENDATIONS
* Proper site selection is very important to effectively remove P from
applied waste waters. Only at moderate rates of P application, sandy
soils are saturated with CaHPOj,«2H20 which has the highest solubility of
all the P reaction products known. Since more P is expected to move
under these conditions, sandy soils like U and AB should be avoided as
waste disposal sites.
* In order to minimize the movement of P in alkaline soils it would be
desirable to have hydroxyapatite present in the soils. This could be
accomplished by controlling pH, rate of P application, and time intervals
between applications.
* If removing P from waste waters was the only consideration it would be
logical to apply waste waters to acid soils since aluminum and iron
phosphates that form under acid soil conditions have very low solubilities.
However, in practice, liming of waste treated acid soils may be required
to immobilize heavy metals. Phosphorus solubilities in lime treated
acid soils will be controlled by relatively more soluble calcium phosphate
compounds.
* Applications of waste waters bring about reducing conditions and pH
changes in the soil zone and the results could be different from those
obtained by applying CaCHaPOij^'HzO to these soils. Hence the P
reactions should be determined by applying waste waters as such to soils.
* In this study P at a given rate was added only once, and the rate of
transformation of initial and intermediary compounds formed was
determined. The rates should be determined under repeated application
of P to the soils.
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SECTION 4
METHODS AND MATERIALS
Physical and chemical properties of soils used in this work were previ-
ously reported (5). To further characterize the chemical and physical
properties, clay minerals in each soil were determined by using X-ray diffrac-
tion techniques (Table 1).
TABLE 1. CLAY MINERALOGY OF THE SOILS USED IN THIS INVESTIGATION
Soil
Clay Minerals
B
D
E
U
Y
AA
AB
AC
Illite, Kaolinite, and mixed layered minerals (1:1 Illite
and Montmorillonite).
Illite, Montmorillonite, and Kaolinite
Illite, Kaolinite, and mixed layered minerals (1:1 Illite
and Montmorillonite). 22.5% CaC03 on soil dry wt. basis.
Illite, Montmorillonite, Kaolinite. 6.6% CaC03 on soil
dry wt. basis.
Chlorite
Mg+2 rich Chlorite
Mg+2 rich Chlorite, Kaolinite and Illite
Illite, Montmorillonite, and Kaolinite. 6.6% CaC03 on
soil dry wt. basis.
Illite and Kaolinite
X-ray diffraction work did not show the presence of gibbsite in acid
soils B, D, U, Y, or AA. For gibbsite to be detectable using X-ray diffrac-
tion, approximately 5% of the clay sized particles would have to be present
as gibbsite. An alternate procedure based on solubility products can be
effective in low concentrations. Identification of the specific compound
can be made by comparing calculated ion activity products with solubility
constants of the various crystalline forms. After measuring the Al1' ion
activity in soil extracts, the ion activity products (pAl+3pOH) were calcu-
lated as listed in Table 2. The reported pK (negative log of the ion
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activity product) values ranged from 32.34 for amorphous A1(OH)3(6) to
33.8 for crystalline gibbsite (7). Thus, indicating amorphous A1(OH)3 in
soils U and AA and crystalline gibbsite in soils B, D, and Y.
TABLE 2. CALCULATED ION ACTIVITY PRODUCTS (-LOG IAP)
OF GIBBSITE IN THE ACID SOILS
Soil
B
D
U
Y
AA
-log IAP
(pAl + 3pOH)
34.52
33.35
32.37
33.54
32.46
Several scientists used solubility criteria to show the existence of
variscite (8), strengite (9), and several calcium phosphates as CaHPOif,
CaHPOi^HaO, Cai^POi,) 3*24H20, Caio (OH)2(POO6 and CaioF2(POif)6 (10 - 16).
The same basic principles were used to obtain the solubility data in these
experiments. Phosphorus was reacted with soils in two different ways.
Fifty ml of 0*01 M CaCl2 containing 30 and 12 ppm P was added to 15 g of
soil in centrifuge tubes to give 90 and 40 ppm P on a soil basis. Reagent
grade (NH,l)2HP0lf and Ca(H2PO^)2.H20 were used as P sources. Adequate aera-
tion was provided to prevent reducing conditions and C02 accumulation during
the experiment. Sufficient replications were made to facilitate sampling at
the end of 1, 3, 10, 30, 100, 300, 1000 and 3000 hours.
In the second method, desired P concentrations as Ca(H2POit)2*H20 were
mixed with soil, wet to field capacity and stored in plexiglas containers.
Deionized distilled water was added at regular intervals to maintain constant
moisture levels. A portion of the soil sample was taken at desired time
intervals and was dried immediately. Ten and 20 g of dried sample were
shaken with 50 ml of 0.01 M CaGl2 for two hours and the data obtained were
extrapolated to Zero dilution (10).
Since method of incubation had no significant influence on the results,
data from the second method of incubation are presented in this report.
pH in the suspensions was measured with a Fisher Accumet pH meter.
Phosphorus in the filtered solutions was measured by the Riley Ascorbic Acid
method as described in "Manual of Methods for Chemical Analysis of Water and
Wastes" (18). From the total P concentrations, the values of HsPOi,, H2POI»~
HPOi>— and P0i»were calculated by using the following equations
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= P
(H)3 +
(H)
(H) +
HPO
~2
(H)3 +
PO
-3
(H)3 +
K3K2K1
where KI, Ka, and K3 are 1st, 2nd and 3rd dissociation constants of phosphoric
acid; 7.51 x 10~3, 6.33 x 10~8, and 4.73 x 10~10 respectively. Calculated P
fractions at various pH values are shown in Appendix Table 1.
After measuring Al+3 in soil extracts on a 305B Perkin-Elmer atomic
absorption spectrophotometer with a graphite furnace, aluminum activities
were calculated as shown by Lindsay, Peech, and Clark (17).
Calcium and Mg 2 concentrations were measured with a Perkin-Elmer 303
atomic absorption spectrophotometer. The activity coefficient f^ was calcu-
lated by using the equation
-log f± =
0.506 Z /IT
-
+ 0.329 a T/~\
+ 3
where y is the ionic strength, Z-^ is the valence of the ion,
by Kielland (19), and g is -0.257 (20).
is 6 as given
The data were interpreted by using the solubility diagrams shown in
Figs. 1 and 2. Also the ion activity products -log (IAP) were calculated
and compared with the known solubility product constants (pKgp) of various
P compounds. Table 3 gives the pKSp values of various P compounds used to
interpret the data.
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8
O
D_
31
O,
Il-
O
\-
2 0 2.2 2.4- 2.6 2.8 3 0
FIG. 1. SOLUBILITY DIAGRAM FOR VARISCITE AND GIBBSITE IN SOILS AT 25 C
ID
U 0 5.0 6.0 7.0 8.0
pH-0.5pCa
FIG. 2. SOLUBILITY DIAGRAM FOR CALCIUM PHOSPHATE COMPOUNDS IN SOILS AT 25 C
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TABLE 3. REPORTED SOLUBILITY PRODUCT CONSTANTS (pKgp)
AND DISSOCIATION CONSTANTS AT 25°C.
Compound
CaHPO -2H20 (DCPD)
CaHP04
Ca3(P04)2 (TCP)
Ca4H(P04)3'2JgH20 (OCP)
Ca1Q(OH)2(P04)6 (HA)
Al (OH) _ (Amorphous)
A1(OH)3 (Gibbsite)
A1P04»2H20 (Variscite)
CaC03 (Calcite)
Solubility Expression
pCa + pHP04
pCA + pHP04
3pCa + 2pP04
4pCa + pH + 3pP04
10 pCa + 6pP04 + 2pOH
pAl + 3pOH
pAl + 3pOH
pAl + 2pOH + pH2P04
pH - pCa + % log PC02
pK
sp
6.56
6.66
26.0
46.91
113.7
32.34
33.8
30.5
4.93
Source
20
7
6
20
7
6
7
8
21
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SECTION 5
RESULTS AND DISCUSSION
IN SITU PHOSPHORUS
In considering soil as a possible medium for P removal from applied waste
waters, the fate of both applied and in situ phosphorus must be understood.
Information obtained from analyzing the 0.01 M CaCl2 extracts of untreated
soils (Tables 4 and 5) was used to identify the compounds governing the P
solubility.
TABLE 4. pH, P, Ca, Mg, Al AND ION ACTIVITY PRODUCTS (-LOG IAP VALUES)
OF VARISCITE MEASURED IN 0.01 M CaCl2 EXTRACTS OF FIVE UNTREATED
ACID SOILS.
5011 "H P Ca Mg Al (pA1
B
D
U
Y
AA
4.20
4.80
4.90
4.40
5.15
0.017
0.013
0.022
0.463
0.087
279
242
345
302
311
ppm - — -
31.8
45.7
3.4
22.8
11.5
0.710
0.206
0.663
1.800
0.190
30.98
30.53
29.68
28.77
29.17
Phosphorus concentrations in the equilibrium extracts of untreated acid
soils ranged from 0.013 to 0.463 ppm. Ion activity products indicated
crystalline variscite in Soils B and D. Equilibrium solutions of Soils U, Y,
and AA were supersaturated with respect to variscite, indicating that these
soils may have been treated with P prior to sample collection. Upon aging,
however, these ion activity product values generally approach the solubility
product of variscite.
Calculated ion activity products for alkaline soils (Table 5) indicated
octacalcium phosphate (OCP) in Soils E and AB, and tricalcium phosphate in
Soil 0. Hydroxyapatite (HA) controlled P solubility in the untreated neutral
Soil AC.
10
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TABLE 5. SOLUBILITY DATA FOR 3 UNTREATED ALKALINE SOILS AND ONE NEUTRAL SOIL
Soil pH P Ca Mg P Compound
E
0
AB
AC
7.70
8.10
7.80
6.00
0.124
0.216
0.216
0.044
381
244
317
327
3.9
19.5
24.0
8.6
*
Ca4H(P04)3'2lsH20 (47.2 )
Ca3(P04)2 (26.07)
Ca4H(P04) *2lsH 0 (46.36)
Ca1Q(OH)2(P04)6 (119.62)
*
Calculated -log LAP values for the indicated compounds.
Tricalcium phosphate and octacalcium phosphate are not stable and will
be converted to less soluble hydroxyapatite.
REACTIONS IN ACID SOILS
Solubility data for the phosphate treated acid Soils B, D, U, Y and AA
are presented in Appendix Table 2. Soils B, D, and AA with high clay content
fixed more phosphorus than U and Y, having lower amounts of clay. At 100 ppm
(soil basis) rate, P in extracts of Soil B, D, and AA decreased by more than
200-fold in less than an hour compared to 50- and 6-fold decreases in Soils Y
and U respectively. Phosphorus fixation rate which was rapid in the beginning
decreased with time.
Aluminum hydroxide potentials (pH - 1/3 pAl) and pH values in CaCla sus-
pensions of the acid soils increased with time of incubation at any given
rate of P application. pH of soil extracts decreased with increasing amount
of applied phosphate. A decrease in the values of pH - 1/3 pAl with increased
P rates was reported by Lindsay, Clark, and Peech (8). In this study, where
100, 40, 25 and 12.5 ppm P (soil basis) rates were compared, highest aluminum
hydroxide potentials were noted at 40 and 25 ppm (soil basis) rates compared
to 100 and 12.5 ppm P rates.
It is evident from Appendix Table 2 that the ion activity products of
variscite in Soils B and D were lower in the beginning, especially at 100 ppm
P rate, and approached the reported pKsp value of 30.5 with time. The solu-
bility data for Soils B and D are plotted in Figs. 3 and 4. After adding
100 ppm P Soil B yielded extracts that were supersaturated with respect to
variscite and undersaturated with gibbsite. Almost immediately after adding
25 and 12.5 ppm P, variscite controlled P solubility.
Extracts of Soil D after adding 100, 40, and 25 ppm P (soil basis) were
supersaturated with both variscite and gibbsite. The soil solution was in
equilibrium with variscite in less than an hour after adding 12.5 ppm P.
11
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FIG. 3. EFFECT OF PHOSPHATE ADDITION ON THE ALUMINUM AND PHOSPHORIC ACID
POTENTIALS IN SOIL-B.
8-
O
cu
10-
DC
Q,
11-
12-
2
SOIL B
ppm P-100
8-
9-
O
Q_
Q,
0 2.2 2.4 2.6 2.8 3 0
pH-V3pfil
11-
12-
2
SOIL B
ppm P-25
t | i | I
0 2.2 2.4 2.6 2.8 3 0
O
OL.
cu
10-
11-
12
SOIL B
ppm P—12.5
T—i—i—i—i—i—i—i—1~
2.0 2.2 2.4 2.6 2.8 3.0
PH-V3pFU
Untreated soil
12
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FIG. 4. EFFECT OF PHOSPHATE ADDITION ON THE ALUMINUM AND PHOSPHORIC ACID
POTENTIALS IN SOIL-D.
10-
o
Q_
0«
o:
a
12-
13
©
SOIL D
ppm P-100
2.6 2.8 3.0 3.2
10-
O
QL
12-
3.U
13-
2
I • I •i »
\
o
SOIL D
ppm P-10
6 2.8 3.0 3.2 3.4
pH-'/spRl
10-
O
a_
12-
o
SOIL D
ppm P-25
o
10-
o
0-
3*11-
o,
12-
2.8 3.0 3.2 3 IJ
13-
2
SOIL D
ppm P-12.5
i • i » i
2.8 3.0 3.2
Untreated soil
13
-------
Soils U, Y and AA continued to yield extracts that were supersaturated
with respect to variscite during the entire aging period. Slow rate of
variscite formation is expected and reported (8). According to Wright and
Peech (9), lower ion activity products of variscite may be attributed to the
presence of extremely small crystals of variscite having higher solubility
than particles of larger size. More complex phosphates like tarnakites,
which are expected to form when orthophosphates are added to acid soils (22),
have higher solubilities than variscite. So the observed low ion activity
products might be due to the formation of small crystals of variscite or
formation of complex phosphates like tarnakites.
Upon aging, the phosphate treated soils had higher aluminum hydroxide
potentials and variscite ion activity products than the corresponding un-
treated soils. This is not peculiar since the data on the original soils
were obtained prior to P treatments; changes in pH, P and Al concentrations
of phosphate untreated soils with time of incubation were not monitored.
REACTIONS IN ALKALINE SOILS
Concentrations of P, Ca and Mg, and pH values in 0.01 M CaCla extracts
of alkaline soils and the calculated lime (pH - %pCa) and phosphate CspCa +
pHaPOjj) potentials and ion. activity products are included in Appendix Table 3.
In general, P applications lowered the pHaPOu values which with time of incu-
bation tended to approach those of phosphate untreated soils. pH values and
lime potentials of phosphate treated soils followed no particular trend during
incubation. In most cases, a gradual increase followed by a decrease in pH
values was noticed with a corresponding change in the equilibrium P concen-
tration; increased pH lowered the P concentration and vice versa. This was
more so at the highest P rates. Changes in COa partial pressure during
incubation could have caused this kind of unusual fluctuations. Decreased
suspension pH values with increased P rates was noticed by Jensen (11), in
several calcareous soils. In this study, equilibrium pH values in Soil AB
decreased slightly, and in Soils E and 0 increased slightly with increasing
P rates.
Soils E and 0 immobilized more P in less time than Soil AB. Soil AB,
with a comparatively low clay content, had a very poor P fixation capacity.
One thousand hours after adding 90 ppm P, a substantial amount (^5 ppm) of P
was still left in the soil solution. From the solubility data, it is evident
that additions of only 100 ppm P saturated this soil with respect to CaHPO^*
2H20. Unacceptable levels of P are likely to move down through this soil
under heavy and repeated applications of waste waters.
Lime and phosphate potentials obtained from the measurements made of the
soil samples taken during incubation are plotted in Figs. 5, 6 and 7 for
Soils E, 0 and AB respectively. These soils yielded extracts that were
super- or undersaturated and sometimes in equilibrium, with the known calcium
phosphates CaHPOi^HaO, CaHPOij, Ca3(POif)2, Ca^H(POif)3'2%H20, and Caio(OH)2
(POO 6- Soil E in the presence of 25 and 12.5 ppm added P, yielded extracts
that were supersaturated with hydroxyapatite and had higher phosphate
14
-------
FIG. 5. CHANGES IN LIME AND PHOSPHATE POTENTIALS IN SOIL - E BY ADDING
100, 40, 25, AND 12.5 ppm P.
SOIL E ppm P-100
SOIL E ppm P-UO
5.0 6.0 7.0
pH-0. 5pCa
8.0
5.0 6.0 7.0
pH-0.5pCa
8.0
SOIL E ppm P-25
SOIL E ppm P-12.5
10
U.O 5.0 6.0 7.0
pH-0.5pCa
8 0
pH-0.5pCa
Untreated soil
15
-------
FIG. 6. CHANGES IN LIME AND PHOSPHATE POTENTIALS IN SOIL - 0 BY ADDING
100, 40, 25, AND 12.5 ppm P.
SOIL 0 ppm P-
• ^^^""^"^^^^^^^^^"^^^^^^^^""""^^^"^^T"
100
SOIL 0 ppm P-UO
5.0 6.0 7.0 8.0
10
u.o
pH-0.5pCa
pH-0.5pCa
SOIL 0 ppm P-25
SOIL 0 ppm P-12.5
pH-0.5pCa
pH-0.5pCa
Untreated soil
16
-------
FIG. 7. CHANGES IN LIME AND PHOSPHATE POTENTIALS IN SOIL - AB BY ADDING
100, 40, 25, AND 12.5 ppm P-
SOIL flB ppm P-90
5.0 6.0 7.0
pH-0.5pCa
8.0
SOIL flB ppm P-UO
U-T 1 v I 1 1 1 1 r-
10
4.0 5.0 6.0
pH-0.5pCa
SOIL flB ppm P-25
SOIL flB ppm P-12.5
U 0
U.O 5.0 6.0 7.0 8.0
pH-0.5pCa
pH-0. 5pCa
Untreated soil
17
-------
FIG. 8. CHANGES IN LIME AND PHOSPHATE POTENTIALS IN SOIL - AC BY ADDING
100, 40, 25, AND 12.5 ppm P.
SOIL flC ppm P-100
SOIL RC ppm P-UO
5-
o
a. 61
CM
-------
potentials than the original sample. This suggests a further reaction of
in situ phosphorus along with the added P .
The phosphate potentials of Soils 0 and AB increased to reach those of
untreated samples. The rate of transformation was P rate dependent; slower
with increased P additions. Soil 0 when treated with 25 and 12.5 ppm P was
in equilibrium with octacalcium phosphate with calculated ion activity pro-
ducts ranging between 46 and 47. Aslyng (10), and Weber and Mattingly (13)
reported solubility data consistent with the existence of octacalcium
phosphate for some Rothamsted soils.
The calculated ion activity products of CasCPOOa at 1000 and 3000 hours
after adding 100 ppm P to Soil 0 were 26.02 and 26.09; also the ion activity
product of P untreated soil was 26.07. These ion activity products agree
with the reported pKsp value of 26 for Ca3(P0lt)2. It is likely that Ca3(POi»)2
exists in soils as an unstable intermediary reaction product which with time
changes to less soluble octacalcium phosphate and hydroxyapatite .
REACTIONS IN A NEUTRAL SOIL
Solubility data for Soil AC are presented in Appendix Table 4.
Phosphorus applications in general lowered the pH, and lime and phosphate
potentials. Depending on the rate of P application, the soil yielded
extracts that were supersaturated or in equilibrium with hydroxyapatite
(Fig. 8). When 100 ppm P was added the extracts were undersaturated with
respect to octacalcium phosphate and supersaturated with respect to hydroxy-
apatite until 1000 hours. At 3000 hours the soil solution was in equilibrium
with hydroxyapatite with a calculated ion activity product (lOpCa + 6pPOij +
2pOH) of 113.2. Application of 40 ppm P supersaturated the soil with respect
to HA until 1000 hours. Three hundred hours after adding 25 ppm P, HA con-
trolled P solubility. Solubility data showed the existence of HA, 3 hours
after adding 12.5 ppm P. According to several scientists (13, 16), acid
soils limed to near neutral pH values were in equilibrium with hydroxyapatite.
X-RAY DIFFRACTION WORK
A method very similar to that of Bell and Black (23) was used to identify
the reaction products of applied orthophosphates. Monocalcium phosphate
monohydrate was mixed with soils and incubated in plexiglas cylinders. The
cylinders were kept in a saturated atmosphere in a desiccator to prevent
water loss by evaporation. Precaution was taken to provide adequate aeration
at the reacting surface. X-ray diffraction patterns of the samples from the
reaction surface were obtained by a Philips X-ray diffractometer using nickel-
filtered Cu K a radiation with a pulse height analyzer. Identifications were
made by comparing the X-ray diffraction patterns obtained with those pub-
lished by Lehr et al. (24). Peak heights were used to quantitatively deter-
mine the reaction products. The quantitative data thus obtained are subject
to ± 5 to 10% error.
19
-------
Applied Ca(H2POif)2*H20 transformed to CaHPOit and CaHPOt^ZHaO in all the
soils, which remained unchanged for more than a year. Proportions of CaHPOi*
and CaHPOi»'2H20 for one acid - (Soil B), and one neutral - (Soil AC), and one
alkaline soil (Soil 0) are presented in Appendix Table 5. These results
agree well with those reported elsewhere. Bell and Black (23) identified
CaHPOi,»2H20 and CaHPOi* by applying Ca(H2POit)2'H20 to slightly acid and alka-
line soils. Moreno et al. (15) mixed very high concentrations of P with an
acid soil and showed the soil solution was saturated with respect to CaHPO^*
2H20 in less than an hour and remained so after one month. It is a general
observation that phosphate fertilizers when banded supply more P to plants
than when broadcasted; and this phenomenon is more so in the acid soils.
Phosphorus concentrations are higher in the banding site and the soil zone is
saturated with CaHPOi* • 2H20. Broadcasting favors aluminum and iron phosphates
in acid soils and octacalcium phosphate in alkaline soils which are less
soluble than CaHPOit*2H20.
Applied Ca(H2POif)2-H20 should transform to the next less soluble compound
CaHPOi,-2H20. However, a close look at the results in Appendix Table 5 reveals
that CaHPOij precipitated earlier than CaHP(V2H20, The transformation of
CaHPOit«2H20 to CaHPOit might have occurred while drying the samples for X-ray
diffraction analysis.
20
-------
SECTION 6
REFERENCES
1. Adriano, D. C., L. T. Novak, A. E. Erickson, A. R. Wolcott, and B. G.
Ellis. 1975. Effect of long term land disposal by spray irrigation
of food processing wastes on some chemical properties of the soil and
subsurface waters. J. Environ. Qual. 4:242-248.
2. Fiskell, J. G. A., and W. F. Spencer. 1964. Forms of phosphate
in Lakeland fine sand after six years of heavy phosphate and lime
applications. Soil Sci. 97:320-327-
3. Reneau, Jr., R. B., and D. E. Pettry. 1976. Phosphorus distribution
from septic tank effluent in Coastal Plain soils. J. Environ. Qual.
5:34-39.
4. Lund, L. J., A. L. Page, and C. 0. Nelson. 1976. Nitrogen and
phosphorus levels in soils beneath sewage disposal ponds. J. Environ.
Qual. 5:26-30.
5. Enfield, C. G., C. C. Harlin, Jr., and B. E. Bledsoe. 1976. Comparison
of five kinetic models for orthophosphate reactions in mineral soils.
Soil Sci. Soc. Am. J. 40:243-249.
6. Sillen, L. G., and A. C. Martell. 1964. Stability constants of metal
ion - complexes. 2nd ed. Special publication No. 17. The Chemical
Society, London. 754 P.
7. Lindsay, W. L., and E. C. Moreno. 1960. Phosphate phase equilibria
in soils. Soil Sci. Soc. Am. Proc. 24:177-182.
8. Lindsay, W. L., M. Peech, and J. S. Clark. 1959. Solubility criteria
for the existence of variscite in soils. Soil Sci. Soc. Am. Proc.
23:357-360.
9. Wright, Bill C., and Michael Peech. 1960. Characterization of
phosphate reaction products in acid soils by the application of
solubility criteria. Soil Sci. 90:32-43.
10. Aslyng, H. C. 1954. The lime and phosphate potentials of soils; the
solubility and availability of phosphates. Roy. Vet. and Agr. Coll.,
Copenhagen, Den. Yearbook Reprint, pp. 1-50.
21
-------
11. Jensen, H. E. 1971. Phosphate solubility in Danish soils equilibrated
with solutions of differing phosphate concentrations. J. Soil Sci.
22:261-266.
12. Clark, J. S., and M. Peech. 1955. Solubility criteria for the
existence of calcium and aluminum phosphates in soils. Soil Sci.
Soc. Am. Proc. 19:171-174.
13. Weber, M. D., and G. E. Mattingly. 1970. Inorganic soil phosphorus:
II. Changes in monocalcium phosphate and lime potentials on mixing
and liming soils. J. Soil Sci. 21:121-126.
14. Larsen, S., and A. E. Widdowson. 1970. Evidence of dicalcium phosphate
precipitation in a calcareous soil. J. Soil Sci. 21:364-367-
15. Moreno, E. C., W. L. Lindsay, and G. Osborn. 1960. Reactions of
dicalcium phosphate dihydrate in soils. Soil Sci. 90:58-68.
16. Withee, L. V., and Roscoe Ellis, Jr. 1965. Change of phosphate
potentials of calcareous soils on adding phosphorus. Soil Sci. Soc.
Am. Proc. 29:511-514.
17. Lindsay, W. L., M. Peech, and J. S. Clark. 1959. Determination of
aluminum ion activity in soil extracts. Soil Sci. Soc. Am. Proc.
23:266-269.
18. Manual of methods for chemical analysis of water and wastes. 1974.
Environmental Protection Agency, Washington, D.C. Publication number
EPA-625-/ 6-74-003. 298 P.
19. Kielland, J. 1937. Individual activity coefficients of ions in
aqeous solutions. J. Am. Chem. Soc. 59:1675-1678.
20. Moreno, E. C., W. E. Brown, and G. Osborn. 1960. Solubility of
dicalcium phosphate dihydrate in aqeous solutions. Soil Sci. Soc.
Am. Proc. 24:94-98.
21. Turner, R. C., and J. S. Clark. 1956. The pH of calcareous soils.
Soil Sci. 82:337-341.
22. Lindsay, W. L., and H. F. Stephenson. 1959. Nature of the reactions
of monocalcium phosphate monohydrate in soils. IV. Repeated reactions
with metastable triple-point solution. Soil Sci. Soc. Am. Proc.
23:440-445.
23. Bell, L. C., and C. A. Black. 1970. Crystalline phosphates produced
by interaction of orthophosphate fertilizers with slightly acid and
alkaline soils. Soil Sci. Soc. Am. Proc. 34:735-740.
24. Lehr, J. R., E. H. Brown, A. W. Frazier, J. P. Smith, and R. D. Thrasher.
1967. Crystallographic properties of fertilizer compounds. Tennessee
Valley Authority Chem. Engin. Bull. 6. 166 P.
22
-------
APPENDIX TABLE 1
Table 1. Fraction of total P as
values.
_,
-2
_3
_
, E2POt+, HPOi^ , POit at various
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
PH
.00
.05
.10
.15
.20
.25
.30
.35
.AO
,A5
.50
.55
.60
.65
.70
.75
.80
.65
.90
.95
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
H3PC4
.131E-01
.117K-01
.105E-01
.933E-02
.832E-02
.742E-02
.662E-02
.590E-02
.526E-02
.A69E-02
.410E-02
.373E-C2
.333E-02
.2S6E-02
.26AE-D2
.235E-02
.210E-02
.107E-02
.167E-02
.IA8E-02
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
RACTI'JN OF
H2PC4
.986E
.988E
.989E
.990E
.991E
.991E
.992E
.993E
.993E
.9<54E
.99AE
.994E
.9S4E
.99AE
.99AE
.9SAE
.99AE
.9SAE
.993E
.993E
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
TOTAL
H
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
P04
624E-03
701E-03
7S3E-03
885E-C3
99AE-03
112F-02
125E-02
1A1E-02
158E-02
177E-02
199E-C2
223E-02
251E-C2
281E-02
315E-C2
35AE-02
3976-02
AA5E-02,
A99E-02
560E-02
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
PDA
2955-11
372E-11
469E-11
591E-11
745E-11
939E-11
113E-10
149E-10
183E-10
236E-10
29S£-10
375E-13
A72E-1U
59'tE-lO
743E-10
9A1E-10
UOE-09
1A9E-09
IP8E-09
236E-09
23
-------
PH
5.00
5.05
5.10
5.15
5.20
5.25
5.30
5.35
5.40
5.45
5.50
5.55
5.60
5.65
5.70
5.75
5.80
5.65
5. SO
5.95
H3PC4
0.1B2E-02
0.118E-02
0.105E-02
0.933E-03
0.831E-03
0.740E-03
0.659E-03
0.586E-03
0.522E-03
0.464E-03
0.413E-03
0.367E-03
0.326E-03
0.290E-03
0.257E-03
0.229E-03
0.203E-03
0.180F-03
0.160E-03
0.141E-03
— FRATT IPN PF
r"M\*» Awl* U~
I-2PC4
0.9S2E 00
0.992E 00
0.991E 00
0.990E 00
0.989E 00
0.968E 00
0.987E 00
0.985E 00
0.984E 00
C.982E 09
0.980E 00
O.S78E 00
0.975E 00
0.972E 00
0.569E 00
0.965E 00
0.961E 00
0.957E 00
0.952E 00
0.946E 00
TfTAI D AC* ___
HP04
0.628E-C2
0.704E-02
0.790C-C2
0.885E-C2
0.992E-C2
0. 111E-01
0.125E-01
0.140E-CI
0.156E-01
0.1755-01
0.196E-01
0.220E-01
0.246E-C1
0.275E-01
0.307E-01
0.344E-01
0.384E-01
0.429E-01
0.479E-01
0.534E-01
P04
0.297E-09
0.374E-0<>
0.470E-09
0.592E-09
0.744E-09
0.*)36E-09
o.iiae-03
0.143E-08
0.186E-08
0.234E-03
0.293E-00
0.3&9E-03
0.463E-08
0.581E-08
0.729E-OB
0.914E-03
0.115E-07
0.144E-07
0. 180E-07
0.225E-07
APPENDIX TABLE 1 (continued)
24
-------
PH
6.
6.
6.
6.
6.
6.
6.
6.
6.
00
C5
10
15
20
25
30
35
40
£.45
6.
£.
6.
6.
6.
6.
6.
6.
6.
6.
50
55
60
65
70
75
60
85
90
95
H3PC4
0.125E-03
0.111F-03
0.980E-04
0.865E-04
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.764E-04
•673E-04
.593E-04
.521E-04
.457E-04
.401E-04
.351E-04
.306E-04
.267E-04
.232C-04
.202E-04
.175C-04
.151E-04
.130E-04
.112E-04
.955E-05
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
KAWI 11
H2PC4
.94CE
.934E
.926E
.918E
.9C<5E
.8S9C
.888E
.876E
.863E
.84<3E
.833E
.817E
.7S96
.780E
.759E
.737E
.715E
.691E
.665E
.639E
HP04
00
00
00
00
03
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
595E-C1
663E-CI
738S-01
821E-01
912E-01
101E
112E
124E
137E
151E
167E
183E
201E
220E
241 E
262E
285t
309E
335E
361E
CO
00
00
00
00
CO
00
00
00
00
00
00
00
00
00
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
P04
282E-C7
352E-07
439E-07
548E-07
683E-07
851E-07
106E-06
131E-06
163E-06
202E-06
249E-06
3J8E-06
379E-06
466E-06
571E-06
698E-06
352E-06
104E-C5
126E-05
152E-05
APPENDIX TABLE 1 (continued)
25
-------
PH
7.
7.
7.
7.
7.
7.
7.
7.
7.
7.
7.
7.
7.
7.
7.
7.
7.
7.
7.
7.
CO
05
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
H3PC4
.816E-05
.694E-05
.589E-05
.498E-05
.419E-05
.352E-05
.2S5E-05
.246E-05
.205E-05
.170E-05
.140E-C5
.116E-05
.950E-OA
.779E-06
.637E-06
.519E-06
.423E-06
.343E-06
.278E-06
.225E-06
— I-
0
0
0
0
0
0
0
0
a
0
0
0
0
0
0
0
0
0
0
0
KALI 11
H2PC4
.612E
.585F
.557E
.528E
.4SSE
..470E
.442E
.414E
.386E
.359E
.333E
.3C8E
.284E
.261E
.240E
.219E
.20CE
.182E
.166E
.151E
JN CF TCTAL P AS:
HP04
00
00
00
00
ao
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
388E
415E
443E
472E
501E
53 OE
55 8E
586E
614E
641E
667E
692E
716E
739E
76 OE
781E
800E
818E
834E
849E
CO
00
00
00
00
00
00
CO
CO
CO
00
CO
CO
00
00
00
00
CO
00
00
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
P04
.183E-C5
.220E-05
.264E-05
.315E-05
.375E-05
.445E-05
.527E-05
.621E-05
.729E-05
.854E-05
.997E-05
.116E-04
.135E-04
.156E-04
.180E-04
.203C-04
.239E-04
.274E-04
.313E-04
.358E-04
APPENDIX TABLE 1 (continued)
26
-------
PH
8.
8.
8.
6.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
00
05
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
0
0
0
0
0
0
C
0
0
0
0
0
0
0
0
0
0
0
0
H3PC4
,l82t-C6
. 146E-06
. 118E-06
.948E-07
.762E-07
.611E-07
.490E-07
.392E-07
.314E-07
.251E-07
.200E-07
.160E-07
.128E-07
.102E-07
.812E-08
.647E-08
.515E-08
.411E-08
.327E-08
0.260E-08
0
0
0
0
0
0
3
0
0
0
0
0
0
0
0
0
0
0
0
0
RACTION OF
H2P04
.136E 00
.123E 00
.112E 00
.1015 00
.9C6E-01
.816E-01
. 734E-01
.659E-01
.592E-01
.531E-01
.476E-01
.426E-01
.382E-01
.342E-01
.3C6E-01
.273E-01
.244E-01
.218E-01
.IS5E-01
.174E-01
TCTAL P A!
HP04
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
864E
877E
8RRE
89 9E
909E
91 3E
92 7E
934E
941E
947E
S52E
95 7E
S62S
966E
969E
972E
S75E
978E
980E
S82E
00
00
CO
00
CO
00
00
00
00
CO
CO
00
CO
00
00
CO
CO
00
00
CO
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
P04
.403E-04
.465E-04
.529E-C4
.601E-04
.682E-04
. 772E-04
.874E-04
.989E-04
.112E-03
. 126E-03
. 142E-03
.161E-03
.181E-03
.204E-03
.230E-03
.259E-03
.291E-J3
.327E-03
.363E-03
.4UE-03
27
-------
APPENDIX TABLE 2
Table 2. Solubility data obtained from adding 100, 40, 25, .,,,d 12 5 ppm
P (soil basis) to acid soils.
TIHE(HHS)
1
3
10
30
100
300
1000
3000
TIHE(HRS)
1
3
10
30
100
300
1000
3000
SOIL- B
P CONCENTRATION- 100 ppn
pH P(Ppm) pH3P04 PH P0 PHPO Ppo
4.00 0.490 6.68 4.81 8.01 16.33
4.00 0.620 6.58 H.70 7.90 16.23
1.00 0.480 6.69 4.82 8.01 16.34
4.00 0.600 6.59 4.72 7.92 16.24
4.10 0.330 6.95 4.98 8.08 16.30
4.30 0.146 7.51 5.33 8.23 16.25
4.00 0.246 6.98 5.11 8.30 16.63
4.20 0.026 8.16 6.08 9.08 17.20
Al (ppm) pAl pAl+3pOH pAl + 2pOH + pH PO
0.880 5.017 35.02 29.82
0.790 5.065 35.06 29.77
0.830 5.044 35.04 29.86
0.820 5.055 35.05 29.77
0.810 5.063 34.76 29.84
0.810 5.078 34.18 29.81
0.810 5.057 35.06 30.16
0.720 5.119 34.52 30.80
28
-------
SOIL- B
P CONCENTRATION-
TIHE(HRS)
3
30
100
300
1000
pH
4.25
4.35
4.50
4.30
4.50
P (ppm)
0.020
0.020
0.015
0.003
0.006
pH PO
3 4
8.32
8.42
8.69
9.19
9.09
25 ppa
pH PO
6.19
6.19
6.32
7.02
6.72
PHP04
9.14
9.04
9.02
9.92
9.41
pPO^
17.22
17.02
16.84
17.94
17.24
TIHB(HRS)
3
30
100
300
1000
il (ppn)
0.720
0.650
0.600
0.500
0.600
PA1
5.121
5.174
5.232
5.283
5.229
pAl+3pOH
34.37
34.12
33.73
34.38
33.73
pAl*2pOH+pH PO
30.81
30.67
30.55
31.70
30.94
APPENDIX TABLE 2 (continued)
29
-------
SOIL- B
P CONCENTRATION- 12.5 ppm
TIHE(HRS)
30
100
1000
pH
4.30
4.20
4.50
P(ppm)
0.012
0.008
0.003
PV°»
8.59
8.67
9.39
pH PO
z *
6.42
6.59
7.02
PHPO%
9.31
9.59
9.72
Ppo4
17.34
17.72
17.54
TIME (MRS)
30
100
1000
Al(ppm)
0.680
0.560
0.600
pfcl
5.131
5.231
5.233
p&l+3pOH
34.23
34.63
33.73
pAl+2pOH+pH PO
30.95
31.42
31.25
APPENDIX TABLE 2 (continued)
30
-------
SOIL- D
P CONCENTRATION- 100 ppa
TINE (BBS)
1
10
30
100
300
3000
pH
4.80
4.80
4.80
4.90
5.10
5.20
P(ppm)
0.173
0.155
0.075
0.060
0.030
0.010
pH PO
r 3 4
7.93
7.98
8.29
8.49
8.99
9.57
pH PO
r 2 4
5.26
5.30
5.62
5.72
6.02
6.50
PHP04
7.65
7.70
8.02
8.01
8.12
8.49
PP04
15.18
15.23
15.54
15.44
15.34
15.62
TIME (BBS)
1
10
30
100
300
3000
Al (ppm)
0.290
0.320
0.350
0.160
0.130
0.100
PA1
5.612
5.567
5.529
5.891
6.057
6.216
pAl+3pOH
33.21
33.17
33.13
33.19
32.76
32.62
pAl*2pOH+pH PO
29.27
29.27
29.55
29.81
29.88
30.31
APPENDIX TABLE 2 (continued)
31
-------
SOIL- D
P CONCENTBATION-
TIHE(HBS)
1
3
10
30
100
300
1000
PH
4.80
4.80
4.90
4.90
4.80
4.90
5.10
P(ppn)
0.130
0.130
0.040
0.020
0.020
0.015
0.016
pH PO
*3 *
8.06
8.06
8.67
8.97
8.87
9.09
9.27
40 ppm
pH PO
5.38
5.38
5.89
6.19
6.19
6.32
6.29
PHP04
7.78
7.78
8.19
8.49
8.59
8.62
8.39
pPO^
15.30
15.30
15.62
15.92
16.12
16.04
15.61
TIHE(HRS)
1
3
10
30
100
300
1000
*1(PPB)
0.175
0.170
0.205
0.270
0.185
0.205
0.215
pAl
5.831
5.843
5.790
5.670
5.798
5.787
5.839
pAl+3pOH
33.43
33.44
33.09
32.97
33.40
33.09
32.54
PAl+2POH*pH2P04
29.61
29.62
29.88
30.06
30.39
30.30
29.93
APPENDIX TABLE 2 (continued)
32
-------
SOIL- D
P COHCENTHATIOH-
25 ppm
TIHE(BRS)
3
30
100
300
1000
pH
4.90
4.90
5.10
4.90
5.40
P (ppm)
0.100
0.033
0.013
0.008
0.001
pH PO
3 4
8.27
8.75
9.36
9.37
10.77
pK PO
2 *
5.49
5.98
6.38
6.59
7.50
PHP04
7.79
8.27
8.48
8.89
9.30
PP<\
15.22
15.70
15.70
16.31
16.22
TIME (BBS)
3
30
100
300
1000
Al(ppn)
0.235
0.100
0.110
0.250
0.110
pAl
5.723
6.096
6.126
5.699
6.276
pAl+3pOH
33.02
33.40
32.83
33.00
32.08
pAl*2pOH+pH PO
29.42
30.27
30.31
30.49
30.97
APPENDIX TABLE 2 (continued)
33
-------
SOIL- D
P CONCENTRATION- 12.5 ppm
XXHE(HBS)
3
30
100
300
1000
pH
4.70
4.65
4.80
4.95
5.10
P(pp»)
0.019
0.023
0.010
0.009
0.004
pH PO
r 3 «
8.79
8.66
9.17
9.37
9.87
PH2P04
6.21
6.13
6.49
6.54
6.89
PHPO^
8.71
8.68
8.89
8.79
8.99
Ppo4
16.34
16.36
16.42
16.16
16.22
TINE (BBS)
3
30
100
300
1000
Al (ppn)
0.140
0.190
0.085
0.075
0.140
PA1
5.897
5.752
6.136
6.234
6.022
pAl+3pOH
33.80
33.80
33.74
33.38
32.72
pAl+2pOH+pH PO
30.71
30.58
31.03
30.87
30.71
APPENDIX TABLE 2 (continued)
34
-------
SOIL- U
P COHCENTBATION- 100 pp>
TIHB(HBS)
1
10
30
100
300
1000
3000
TIHE(HBS)
1
10
30
100
300
1000
3000
pH P
-------
TIME (HBS)
1
3
10
30
100
300
1000
TIHE(HRS)
1
3
10
30
100
300
1000
PH
4.85
4.95
5.10
5.10
5.60
5.80
5.30
11 (ppm)
0.360
0.235
0.220
0.230
0.110
0.175
0.195
SOIL- U
P CONCENTRATION- 40 ppn
P(ppm) PH3P04 pH2PO« PHP04 Ppo
6.400 6.41 3.69 6.04 13.51
5.100 6.61 3.79 6.04 13.41
2.900 7.01 4.03 6.13 13.36
3.800 6.89 3.92 6.01 13.24
0.400 8.38 4.90 6.50 13.22
0.010 10.18 6.51 7.91 14.43
0.010 9.67 6.50 8.40 15.42
p&l pAl+3pOH pAl+2pOH+pH PO^
5.535 32.99 27.52
5.759 32.91 27.65
5.834 32.53 27.67
5.801 32.50 27.52
6.416 31.62 28.12
6.362 30.96 29.27
5.983 32.08 29.88
APPENDIX TABLE 2 (continued)
36
-------
SOIL- 0
P CONCEHTBATIOH- 25 ppn
TIME(HRS)
3
30
100
300
1000
pH
5.10
5.15
5.30
5.10
5.20
P (ppm)
0.700
0.425
0.308
0.028
0.034
pH^PO^
7.63
7.89
8.18
9.02
9.04
PH2P04
4.65
4.87
5.01
6.05
5.96
PHP04
6.75
6.92
6.91
8.15
7.96
PP04
13.97
14.09
13.93
15.37
15.09
TIHE(HRS)
3
30
100
300
1000
Al(ppo)
0.300
0.265
0.205
0.205
0.220
p&l
5.699
5.775
5.960
5.867
5.877
pAl+3pOH
32.40
32.33
32.06
32.57
32.28
p&l+2pOH*pH PO
28.15
28.34
28.37
29.72
29.44
APPENDIX TABLE 2 (continued)
37
-------
TIHE(HBS)
(
3
30
100
300
1000
TIDE (BBS)
3
30
100
300
1000
SOIL- U
P CONCENTRATION- 12.5 ppm
pH P (ppa) pH PO pH PO pHPO pPO
34 Z 4 4 4
4.85 0.195 7.93 5.20 7.55 15.03
4.90 0.115 8.21 5.43 7.73 15.16
5.15 0.034 8.99 5.96 8.01 15.19
5.15 0.026 9.11 6.08 8.13 15.30
5.20 0.020 9.27 6.19 8.19 15.32
Al (ppa) pAl pAl+3pOH pAl+2pOH+pHzPO^
0.360 5.532 32.98 29.04
0.320 5.599 32.90 29.23
0.200 5.897 32.45 29.56
0.175 5.952 32.50 29.73
0.175 5.978 32.38 29.77
APPENDIX TABLE 2 (continued)
38
-------
SOIL- I
P CONCENTRATION- 100 ppra
TINE (BBS)
1
3
10
30
100
300
1000
3000
TIHE(HRS)
1
3
10
30
100
300
1000
3000
pH P(ppm) pH PO pH PO
4.40 2.060 6.46 4.18
4.40 1.960 6.48 4.20
4.40 2.170 6.43 4.16
4.40 2.010 6.47 4.19
4.55 1.560 6.73 4.30
4.60 0.710 7.12 4.64
4.80 0.100 8.17 5.49
4.90 0.090 8.32 5.54
Al (ppn) pAl pAl*3pOH
0.030 6.536 35.34
0.050 6.311 35.11
0.030 6.526 35.33
0.740 5.123 33.92
0.760 5.128 33.48
0.950 5.044 33.24
1.060 5.043 32.64
0.950 5.123 32.42
pHPO pPO
6.98 14.90
7.00 14.93
6.96 14.88
6.99 14.91
6.95 14.72
7.24 14.97
7.89 15.42
7.84 15.26
pAl*2pOH+pH PO
29.92
29.71
29.88
28.51
28.33
28.49
28.94
28.86
APPENDIX TABLE 2 (continued)
39
-------
SOIL- I
P COHCEHTBATION-
40 ppa
HUE (BBS)
pH
P (pp»)
pH PO
r 3 4
pH PO
* 2 *
PHPO,
1
3
10
30
100
300
1000
4.30
4.40
4.40
4.40
4.50
4.80
4.90
1.880
1.580
1.100
1.200
0.740
0.320
0.130
6.40
6.57
6.73
6.69
7.00
7.66
8.16
4.22
4.30
4.45
4.41
4.62
4.99
5.38
7.12
7.09
7.25
7.21
7.32
7.39
7.68
15.14
15.02
15.18
15.14
15.15
14.91
15.10
TIME (BBS)
1
3
10
30
100
300
1000
Al
1
1
1
2
0
0
0
(PP»)
.240
.210
.880
.400
.810
.550
.670
4
4
4
4
5
5
5
PA1
.909
.927
.729
.612
.092
.327
.271
pAl+3pOH
34.
33.
33.
33.
33.
32.
32.
01
73
53
41
59
93
57
pAl+2pOH+pH PO
28
28
28
28
28
28
28
•
•
•
•
•
•
•
53
42
38
23
72
72
85
APPENDIX TABLE 2 (continued)
40
-------
TIME (BBS)
3
30
100
300
1000
TIHE(HBS)
3
30
100
300
1000
SOIL- X
P COKCEHTBATIOH- 25 ppm
pH P(ppn) pH PO pH PO
4.50 0.888 6.92 4.55
4.50 0.800 6.97 4.59
4.70 0.575 7.31 4.73
5.10 0.118 8.40 5.42
5.30 0.089 8.72 5.55
Al (ppm) pAl pAl+3pOH
1.150 4.947 33.45
1.280 4.897 33.40
0.840 5.113 33.01
0.550 5.417 32.12
0.310 5.760 31.86
PHP04 PP04
7.24 15.07
7.29 15.11
7.23 14.86
7.52 14.75
7.45 14.47
pAl+2pOH+pH PO^
28.49
28.49
28.45
28.64
28.71
APPENDIX TABLE 2 (continued)
41
-------
SOIL- I
P COHCENTBATION- 12.5 ppB
TIHB(HBS)
3
30
100
300
1000
pH
4.30
4.30
4.50
5.10
4.60
P (ppa)
0.658
0.183
0.258
0.060
0.078
PHsP04
6.85
7.41
7.46
8.69
8.08
pH PO
r Z 4
4.68
5.23
5.08
5.72
5.60
PHP0<
7.57
8.13
7.78
7.82
8.20
PP04
15.60
16.16
15.61
15.04
15.93
TIHE(BRS)
3
30
100
300
1000
U (ppa)
1.590
1.500
0.530
0.350
0.570
pAl
4.779
4.807
5.282
5.615
5.269
pAl+3pOH
33.88
33.91
33.78
32.32
33.47
pAH-2pOH+pH PO
28.85
29.44
29.36
29.13
29.67
APPENDIX TABLE 2 (continued)
42
-------
TIME (MRS)
1
3
10
30
100
300
1000
3000
IIHB(HRS)
1
3
10
30
100
300
1000
3000
PH
5.20
5.20
5.20
5. HO
6.10
5.60
5.70
4.90
Al (ppn)
0.055
0.205
0.150
0.088
0.301
0.175
0.120
0.360
SOIL- iA
P COHCENTRATION- 100 ppn
P(ppn) PV°« PHj,PO« PHP04 PP04
0.170 8.34 5.27 7.26 14.39
0.213 8.24 5.17 7.17 14.29
0.220 8.23 5.15 7.15 14.28
0.257 8.36 5.09 6.89 13.81
0.092 9.54 5.56 6.66 12.88
0.148 8.81 5.33 6.93 13.66
0.110 9.04 5.46 6.96 13.59
0.019 8.99 6.22 8.51 15.94
pAl pAl+3pOH pAl+2pOH+pH PO
6.485 32.89 29.35
5.911 32.31 28.68
6.047 32.45 28.80
6.380 32.18 28.67
6.363 30.06 27.72
6.208 31.41 28.34
6.447 31.35 28.51
5.550 32.85 29.97
APPENDIX TABLE 2 (continued)
43
-------
SOIL- AA
P CONCEHTRATION
40 pp«
TIME (BBS)
1
3
10
30
100
300
1000
PH
5.10
5.20
5.20
5.30
5.60
5.50
6.70
P(ppa)
0.600
0.150
0.080
0.090
0.010
0.010
0.020
7.69
8.40
8.67
8.72
9.98
9.88
10.89
pHzP°«
4.72
5.32
5.59
5.54
6.50
6.50
6.31
PHPO^
6.82
7.32
7.59
7.44
8.10
8.20
6.81
PPO%
14.04
14.44
14.72
14.47
14.83
15.02
12.43
TIHE(HHS)
1
3
10
30
100
300
1000
Al (ppn)
0.240
0.240
0.180
0.300
0.105
0.160
0.270
pAl
5.801
5.843
5.968
5.791
6.421
6.180
6.979
pAl+3pOH
32.50
32.24
32.37
31.89
31.62
31.68
28.88
pAl+2pOH+pH PO
28.32
28.76
29.16
28.73
29.72
29.68
27.89
APPENDIX TABLE 2 (continued)
44
-------
SOU- AA
P CONCENTBATIOH-
25 pp»
TIHE(HRS)
3
30
100
300
1000
pH
5.40
5.80
6.50
6.60
6.60
P(ppn)
0.108
0.050
0.073
0.030
0.116
pH PO
3 4
8.74
9.48
10.08
10.59
10.00
pR PO
2 4
5.46
5.81
5.71
6.11
5.52
PHP04
7.26
7.21
6.41
6.71
6.12
14.19
13.73
12.23
12.44
11.85
TIME (BBS)
3
30
100
300
1000
Al (ppn)
0.130
0.270
0.430
0.200
0.340
p*l
6.207
6.161
6.576
7.004
6.769
pAl+3pOH
32.01
30.76
29.08
29.20
28.97
pAl+2pOH+pH PO
28.87
28.37
27.28
27.92
27.09
APPENDIX TABLE 2 (continued)
45
-------
SOIL- AA
P CONCEHTBATION- 12.5 ppm
TIME (BBS)
3
30
100
300
1000
pH
5.10
5.50
6.25
6.60
6.75
P(ppm)
0.060
0.007
0.010
0.025
0.071
pH PO
J 4
8.69
10.03
10.66
10.67
10.40
pH PO
r 2 4
5.72
6.65
6.54
6.19
5.77
PHP04
7.82
8.35
7.49
6.79
6.22
pPO^
15.04
15.18
13.56
12.51
11.80
TIHE(HHS)
3
30
100
300
1000
Al (ppm)
0.215
0.070
0.025
0.550
0.180
PA1
5.830
6.535
7.578
6.562
7.191
pAl+3pOH
32.53
32.03
30.83
28.76
28.94
pAl*2pOH+pH PO
29.35
30.19
29.62
27.55
27.46
46
-------
APPENDIX TABLE 3
Table 3. Solubility data obtained from adding 100, 40, 25, and 12.5 ppm
P (soil basis) to alkaline soils E, 0, and AB.
SOIL- E
P COHCEHTRATION-
TIKE(HHS)
1
3
10
30
100
300
1000
3000
PH
7.80
7.80
7.80
7.80
7.85
7.70
7.70
7.60
P(ppm)
0.400
0.561
0.661
0.715
0.510
0.465
0.100
0.085
PH PO
3 4
11.26
11.12
11.04
11.01
11.25
11.02
11.69
11.58
100 ppm
PH PO
2 4
5.59
5. 44
5.37
5.34
5.52
5.44
6.11
6.11
pHPO pPO
4.99 9.51
4.84 9.36
4.77 9.29
4.73 9.26
4.87 9.35
4.94 9.57
5.61 10.24
5.71 10.43
TIHE(HRS)
1
3
10
30
100
300
1000
3000
Ca(ppm)
367.
359.
359.
381.
371.
376.
374.
369.
Mg(ppn)
2.9
2.9
3.1
2.4
1.3
3.4
2.4
2.6
pCa
2.29
2.30
2.30
2.28
2.29
2.28
2.28
2.29
pH-0. 5pCa
6.65
6.65
6.65
6.66
6.71
6.56
6.56
6.46
0.5pCa+pH PO
24
6.73
6.59
6.52
6.47
6.67
6.58
7.25
7.25
TIBE(HRS)
1
3
10
30
100
300
1000
3000
pCa+pHPO
7.28
7.11
7.07
7.01
7.16
7.22
7.89
8.00
3pCa+2pPO 4pCa+pH+3pPO
25.89
25.62
25.48
25.35
25.56
25.98
27.32
27.73
45.50
45.09
44.87
44.69
45.04
45.53
47.54
48.05
10pCa+6pPO +2pOH
92.37
91.57
91.14
90.73
91.27
92.81
96.85
98.28
47
-------
SOIL- E
P CONCENTRATION- 40 ppn
TIHE(HRS)
1
3
10
30
100
300
1000
pH P
7.50 2
7.70 1
7.90 0
7.90 0
7.80 0
7.40 0
7.50 0
(ppn) ;
.370
.000
.360
.500
.010
.020
.010
pv°4
9.97
10.69
11.49
11.35
12.87
11.88
12.34
pH PO
r Z 4
4.59
5.11
5.71
5.57
7.19
6.60
6.97
pHPO pPO
4.29 9.12
4.61 9.24
5.01 9.44
4.87 9.30
6.59 11.11
6.40 11.33
6.67 11.49
TIHE(HRS)
1
3
10
30
100
300
1000
Ca(ppm) Hg
415.
397.
397.
421.
421.
443.
405.
(ppm)
2.6
2.6
3.1
3.4
4.3
7.4
2.3
pCa
2.25
2.26
2.26
2.24
2.24
2.22
2.26
pH-0.5pCa
6.38
6.57
6.77
6.78
6.68
6.29
6.37
0.5pCa+pH PO
2 »
5.72
6.24
6.85
6.69
8.31
7.71
8.10
TIBE(HRS)
1
3
10
30
100
300
1000
pCa+pHPO
6.54
6.87
7.27
7.11
8.83
8.62
8.92
3pCa+2pPO
24.97
25.26
25.66
25.31
28.94
29.30
29.75
4pCa+pH+3pPO
43.84
44.45
45.26
44.75
50.09
50.25
51.00
10pCa*6pPO +2pOH
90.17
90.63
91.45
90.37
101.46
103.32
104.51
APPENDIX TABLE 3 (continued)
48
-------
SOU- B
P CONCEHTBATION-
TIME(HES)
3
30
100
300
1000
PH
7.60
7.30
7.60
7.40
7.40
P(ppn)
0.050
0.044
0.017
0.009
0.003
PH PO
3 4
11.81
11.38
12.28
12.23
12.70
25 ppn
pH PO
2 4
6.34
6.20
6.81
6.95
7.43
pHPO pPO
5.94 10.66
6.10 11.13
6.41 11.13
6.75 11.67
7.23 12.15
IIHE(HRS)
3
30
100
300
1000
Ca(ppn)
367.
358.
359.
358.
322.
Bg(ppm)
2.4
2.9
3.3
3.4
2.6
pCa
2.29
2.30
2.30
2.30
2.34
pH-0.5pCa
6.45
6.15
6.45
6.25
6.23
0.5pCa+pH PO
24
7.48
7.35
7.96
8.10
8.60
TIME(HRS)
3
30
100
300
1000
pCa+pHPO
8.23
8.40
8.70
9.05
9.56
3pCa+2pPO
28.20
29.15
29.16
30.24
31.32
4pCa+pH+3pPO
48.75
49.88
50.18
51.62
53.21
10pCa+6pPO +2pOH
99.69
103.15
102.56
106.23
109.50
APPENDIX TABLE 3 (continued)
49
-------
SOIL- E
P CONCENTRATION- 12.5 ppm
TIHE (UBS)
3
30
100
300
1000
PH
7.40
7.30
7.20
7.40
7.75
P(ppm)
0.018
0.012
0.003
0.011
0.001
pH PO
3 *
11.92
11.94
12.39
12.14
13.78
pH PO
r 2 4
6.65
6.77
7.32
6.86
8.15
PHP04
6.45
6.67
7.31
6.66
7.60
11.37
11.69
12.44
11.59
12.17
TIHE(HHS)
3
30
100
300
1000
Ca(ppm)
363.
371.
374.
344.
376.
Hg(ppm)
2.6
2.2
3.0
3.8
2.2
pCa
2.29
2.29
2.28
2.31
2.28
pH-0.5pCa
6.25
6.16
6.06
6.24
6.61
0.5pCa+pH PO
7.80
7.91
8.46
8.02
9.29
XZHB(HRS)
3
30
100
300
1000
pCa+pHPO
8.74
8.95
9.60
8.97
9.88
3pCa+2pPO
29.63
30.24
31.73
30.11
31.20
4pCa+pH+3pPO
50.70
51.52
53.65
51.41
53.40
10pCa+6pPO +2pOH
104.39
106.42
111.07
105.85
108.37
APPENDIX TABLE 3 (continued)
50
-------
SOU- 0
P CONCZNTBATION-
TIME(HRS)
1
3
10
30
100
300
1000
3000
PH
8.10
8.10
8.10
8.10
8.10
8.00
7.90
7.90
P(ppn)
1.070
1.700
2.020
2.160
1.645
1.280
0.380
0.344
PH PO
3 4
11.39
11.19
11.11
11.08
11.20
11.12
11.47
11.51
100 ppa
pH PO
2 4
5.41
5.21
5.14
5.11
5.23
5.25
5.69
5.73
pHPO pPO
4 *
4.51 8.74
4.31 8.54
4.24 8.46
4.21 8.43
4.33 8.55
4.45 8.77
4.99 9.42
5.03 9.46
TIME (BBS)
1
3
10
30
100
300
1000
3000
Ca(ppm)
367.
302.
240.
215.
211.
238.
253.
250.
Mg(ppn)
23.7
18.6
15.2
13.3
13.1
16.9
17.2
21.2
pCa
2.26
2.33
2.42
2.46
2.47
2.42
2.40
2.39
pH-0.5pCa
6.97
6.93
6.89
6.87
6.87
6.79
6.70
6.70
0.5pCa+pH PO
6.54
6.38
6.35
6.34
6.46
6.46
6.89
6.93
TIBE(HSS)
1
3
10
30
100
300
1000
3000
pCa+pHPO
6.77
6.64
6.65
6.67
6.79
6.86
7.39
7.42
3pCa+2pPO
24.25
24.07
24.18
24.25
24.51
24.80
26.02
26.09
4pCa+pH+3pPO
43.35
43.04
43.16
43.24
43.63
43.98
45.73
45.84
10pCa+6pPO +2pOH
86.81
86.34
86.75
87.01
87.79
88.80
92.64
92.85
APPENDIX TABLE 3 (continued)
51
-------
SOIL- 0
P CONCENTRATION- 40 pp«
TINE (HRS)
1
3
10
30
100
300
1000
PH
7.60
7.60
7.60
7.60
7.50
7.40
7.60
P(ppm) pU PO
1.980
1.800
1.750
1.920
1.560
1.500
0.990
10.22
10.26
10.27
10.23
10.15
10.00
10.52
pH2P°*
4.74
4.78
4.79
4.75
4.78
4.73
5.04
pHPO pPO
4.34 9.06
4.38 9.11
4.39 9.12
4.35 9.08
4.47 9.30
4.53 9.45
4.64 9.37
TIME (BBS)
1
3
10
30
100
300
1000
Ca (ppm)
293.
298.
300.
312.
304.
335.
317.
Hg (ppm)
20.1
19.3
20.1
22.0
21.5
24.6
23.9
pCa
2.34
2.34
2.33
2.31
2.32
2.29
2.31
pH-0.5pCa
6.43
6.43
6.43
6.44
6.34
6.26
6.45
0.5pCa+pH PO
5.91
5.95
5.96
5.91
5.94
5.87
6.20
TIME (HRS)
1
3
10
30
100
300
1000
pCa+pHPO
6.68
6.72
6.72
6.67
6.80
6.81
6.95
3pCa+2pPO
25.15
25.22
25.23
25.10
25.57
25.76
25.65
4pCa+pH+3pPO
44.15
44.26
44.28
44.09
44.69
44.90
44.92
10pCa+6pPO +2pOH
90.58
90.79
90.82
90.42
92.04
92.78
92.06
APPENDIX TABLE 3 (continued)
52
-------
SOIL- 0
P CONCENTRATION- 25 ppn
TIBE(HBS)
3
30
100
300
1000
PH
7.75
7.55
7.70
7.50
7.75
P(ppm) pH PO
0.575
0.610
0.513
0.268
0.169
11.02
10.64
10.98
10.92
11.55
pH PO
2 «
5.39
5.22
5.40
5.54
5.92
pHPO pPO
4.84 9.41
4.87 9.64
4.90 9.52
5.24 10.06
5.37 9.95
TIHE(HBS)
3
30
100
300
1000
Ca (ppn)
243.
244.
253.
252.
235.
Hg (ppn)
17.8
19.7
21.6
23.0
22.7
pea
2.41
2.40
2.39
2.38
2.41
pH-0.5pCa
6.55
6.35
6.51
6.31
6.55
0.5pCa+pH PO
2 4
6.59
6.42
6.59
6.73
7.13
IIBE (BBS)
3
30
100
300
1000
pCa+pHPO
7.25
7.27
7.29
7.62
7.78
3pCa+2pPO
26.05
26.49
26.21
27.28
27.11
HpCa+pH+3pPO
45.62
46.08
45.82
47.23
47.22
10pCa*6pPO +2pOH
93.06
94.76
93.60
97.22
96.25
APPENDIX TABLE 3 (continued)
53
-------
SOIL- 0
P COHCENTRATIOH- 12.5 ppn
TIHE(HRS)
3
30
100
300
1000
pH
7.60
7.60
7.40
7.50
7.60
P(ppm)
0.348
0.193
0.313
0.183
0.224
pH PO
r 3 4
10.97
11.23
10.68
11.08
11.16
pH PO
r 2 4
5.50
5.75
5.41
5.71
5.69
PHP04
5.09
5.35
5.21
5.40
5.29
Ppo4
9.82
10.08
10.13
10.23
10.01
TIME(HRS)
3
30
100
300
1000
Ca(ppm)
248.
248.
241.
239.
244.
Mg (ppm)
18.4
17.9
19.3
21.0
23.2
pea
2.40
2.40
2.41
2.41
2.39
pH-0.5pCa
6.40
6.40
6.20
6.30
6.40
0.5pCa+pH PO
24
6.70
6.95
6.61
6.91
6.88
TIME(HRS)
3
30
100
300
1000
pCa+pHPO
7.49
7.75
7.61
7.81
7.68
3pCa*2pPO
26.84
27.35
27.49
27.68
27.20
4pCa+pEH3pPO
46.66
47.43
47.42
47.81
47.21
10pCa*6pPO +2pOH
95.71
97.26
98.06
98.43
96.80
APPENDIX TABLE 3 (continued)
54
-------
SOIL- AB
P CONCENTBATIOH-
90 ppa
TIHE(HRS)
1
3
10
30
100
300
1000
pH
6.70
6.90
7.00
7.30
7.00
6.80
7.30
P(ppm) ;
20.550
15.680
10.380
3.750
11.700
11.350
4.920
pH PO
7.87
8.25
8.56
9.45
8.51
8.26
9.33
pH PO
2 *
3.30
3.47
3.69
4.27
3.64
3.58
4.15
pHPO pPO
3.80 9.42
3.77 9.20
3.89 9.21
4.17 9.20
3.83 9.16
3.98 9.51
4.05 9.08
TIHB(HBS)
1
3
10
30
100
300
1000
Ca(ppm)
350.
337.
337.
332.
341.
396.
378.
flg(ppn)
20.0
20.1
22.1
24.2
22.6
27.0
29.5
pCa
2.28
2.29
2.29
2.29
2.28
2.23
2.24
pH-0.5pCa
5.56
5.75
5.86
6.15
5.86
5.69
6.18
0.5pCa+pH PO
4.44
4.62
4.83
5.42
4.78
4.70
5.27
VIBE (HRS)
1
3
10
30
100
300
1000
pCa+pHPO
6.08
6.06
6.18
6.46
6.12
6.21
6.29
3pCa*2pPO
25.68
25.27
25.29
25.26
25.17
25.70
24.87
4pCa+pH+3pPO
44.08
43.66
43.79
44.05
43.61
44.23
43.49
10pCa+6pPO +2pOH
93.92
92.30
92.16
91.48
91.80
93.71
90.26
APPENDIX TABLE 3 (continued)
55
-------
SOIL- AB
P CONCEHTBATIOH
40 ppm
TIME(HBS)
1
3
10
30
100
300
1000
TIHE(HBS)
1
3
10
30
100
300
1000
TIHB(HRS)
1
3
10
30
100
300
1000
PH
7.20
7.40
7.50
7.50
7.70
7.90
7.50
Ca (ppm)
353.
334.
334.
350.
334.
375.
381.
pCa+pHPO
6.19
6.22
6.36
6.28
6.67
6.99
6.62
P(ppn)
7.550
5.980
3.950
4.600
1.680
0.670
1.940
Hg (ppn)
23.0
21.6
24.7
24.9
26.1
29.5
28.2
3pCa*2pPO
24.89
24.58
24.65
24.47
24.88
25.06
25.13
pH PO
8.99
9.40
9.75
9.68
10.46
11.22
10.06
pCa
2.27
2.29
2.29
2.27
2.29
2.24
2.24
pH PO
r Z 4
3.91
4.13
4.37
4.31
4.89
5.45
4.68
pH-0.5pCa
6.06
6.25
6.36
6.36
6.56
6.78
6.38
:a*pH+3pP04
43.40
43.12
43.34
43.08
43.87
44.38
44.07
pHPO pPO
3.91 9.04
3.93 8.85
4.07 8.90
4.00 8.83
4.38 9.01
4.74 9.17
4.38 9.20
0.5pCa+pH PO
5.05
5.27
5.52
5.44
6.03
6.57
5.80
10pCa*6pPO *2pOH
90.55
89.23
89.25
88.69
89.51
89.64
90.62
APPENDIX TABLE 3 (continued)
-------
SOIL- AB
P CONCENTRATION- 25 ppa
TIHB(HRS)
3
30
100
300
1000
PH
7.40
7.20
7.50
7.35
7.45
P(ppm)
2.260
1.880
1.600
1.360
1.200
PH PO
3 4
9.83
9.59
10.14
9.97
10.18
pH PO
2 4
4.55
4.52
4.76
4.74
4.86
pHPO pPO
4 4
4.35 9.27
4.52 9.64
4.46 9.29
4.59 9.56
4.61 9.48
SIDE (BBS)
3
30
100
300
1000
Ca(ppn)
323.
321.
330.
327.
324.
Bg(ppm)
21.7
21.1
22.7
22.3
21.9
pCa
2.30
2.31
2.29
2.30
2.30
pH-0.5pCa
6.25
6.05
6.35
6.20
6.30
0.5pCa*pH PO
24
5.70
5.67
5.91
5.89
6.01
TIBB(HRS)
3
30
100
300
1000
pCa+pHPO
6.65
6.82
6.76
6.89
6.91
3pCa+2pPO
25.46
26.20
25.46
26.02
25.87
4pCa+pH*3pPO
44.44
45.35
44.54
45.24
45.10
10pCa+6pPO +2pOH
91.88
94.52
91.68
93.67
93.00
APPENDIX TABLE 3 (continued)
57
-------
SOIL- AB
P CONCEHTHATIOH- 12.5 ppn
TIHB(HBS)
3
30
100
300
1000
pH
7.40
7.40
7.50
7.40
7.70
P (ppm)
0.660
0.688
0.478
0.370
0.452
PH3P04
10.36
10.34
10.66
10.61
11.03
PV°«
5.08
5.07
5.29
5.34
5.46
PHPO^
4.88
4.87
4.99
5.13
4.95
- Pw;~"
9.81
9.79
9.81
10.06
9.58
TIHE(HBS)
3
30
100
300
1000
Ca (ppm)
333.
321.
331.
316.
312.
Hg (ppn)
21.6
21.3
21.8
21.4
21.9
pCa
2.29
2.31
2.30
2.31
2.31
pH-0.5pCa
6.25
6.25
6.35
6.24
6.54
0.5pCa+pH PO
6.23
6.22
6.44
6.49
6.61
TIHE(HRS)
3
30
100
300
1000
pCa+pHPO
7.18
7.17
7.28
7.45
7.27
3pCa+2pPO
26.50
26.50
26.51
27.05
26.10
4pCa+pH+3pPO
46.00
46.00
46.12
46.83
45.70
10pCa+6pPO +2pOH
94.99
95.01
94.83
96.67
93.23
APPENDIX TABLE 3 (continued)
58
-------
APPENDIX TABLE 4
Table A. Solubility data obtained from adding 100, 40, 25, and 12.5 ppm
P (soil basis) to neutral soil - AC.
SOIL- AC
P CONCENTRATION- 100 ppa
TIME (BBS)
1
3
10
30
100
300
1000
3000
pH
5.90
5.90
5.90
6.00
6.40
6.20
6.00
5.80
P(ppn) pH PO^
7.450
7.850
8.700
13.150
5.560
2.980
1.860
1.380
7.42
7.39
7.35
7.27
8.09
8.13
8.12
8.04
pH PO
k r 2 4
3.64
3.62
3.57
3.40
3.81
4.06
4.25
4.37
pHPO^ pPO
4.94 11.36
4.92 11.34
4.87 11.30
4.60 10.92
4.61 10.53
5.06 11.18
5.45 11.77
5.77 12.29
TIHE(HES)
1
3
10
30
100
300
1000
3000
Ca(ppm)
360.
371.
371.
364.
353.
345.
353.
347.
Hg(ppm)
5.2
5.2
5.5
5.9
4.2
6.4
5.3
4.9
pCa
2.29
2.28
2.28
2.29
2.30
2.31
2.30
2.31
pH-0.5pCa
4.75
4.76
4.76
4.86
5.25
5.05
4.85
4.65
0.5pCa+pH PO
4.79
4.76
4.71
4.54
4.96
5.21
5.40
5.52
l
TlttE(HRS)
1
3
10
30
100
300
1000
3000
pCa*pHPO
7.23
7.20
7.15
6.89
6.91
7.36
7.75
8.07
3pCa*2pPO
29.61
29.53
29.44
28.71
27.97
29.29
30.45
31.51
4pCa+pH+3pPO
49.17
49.05
48.92
47.92
47.21
48.97
50.52
51.91
10pCa+6pPO +2pOH
107.32
107.07
106.80
104.42
101.43
105.76
109.64
113.23
59
-------
SOIL- AC
P COHCENTBATION- 40 ppn
TIHE(HRS)
1
3
10
30
100
300
1000
pH
5.80
6.00
6.00
6.00
6.10
6.20
5.90
P (ppm) pH PO
7.380
6.000
3.630
4.580
1.600
0.300
1.890
7.32
7.62
7.83
7.73
8.30
9.13
8.01
pH PO
r 2 *
3.64
3.74
3.96
3.86
4.32
5.06
4.24
pHPO pPO
5.04 11.56
4.94 11.26
5.16 11.48
5.06 11.38
5.42 11.64
6.05 12.18
5.53 11.96
TIBE(HRS)
1
3
10
30
100
300
1000
Ca(ppo)
388.
326.
(162.
410.
388.
445.
413.
Mg(ppm)
4.3
2.7
5.1
4.9
4.5
5.4
4.8
pCa
2.27
2.33
2.20
2.25
2.27
2.22
2.24
pH-0.5pCa
4.67
4.83
4.90
4.88
4.97
5.09
4.78
0.5pCa+pH PO
2 *
4.77
4.91
5.06
4.98
5.45
6.16
5.36
TIBE(HHS)
1
3
10
30
100
300
1000
pCa+pHPO
7.31
7.27
7.36
7.30
7.69
8.27
7.78
3pCa*2pPO
29.93
29.53
29.58
29.50
30.09
31.01
30.65
4pCa*pH+3pPO
49.56
49.13
49.26
49.13
50.10
51.61
50.76
10pCa*6pPO *2pOH
108.46
106.92
106.93
106.75
108.34
110.85
110.40
APPENDIX TABLE 4 (continued)
60
-------
SOIL- AC
P COBCEHTRATION-
TIHE(HBS)
3
30
100
300
1000
PH
6.10
6.40
6.90
6.80
6.40
P(ppm)
2.130
0.550
0.075
0.012
0.060
PH PO
3 4
8.17
9.09
10.57
11.23
10.05
25 ppn
PH PO
2 *
4.20
4.81
5.79
6.56
5.78
pHPO pPO
5.29 11.52
5.61 11.54
6.09 11.52
6.96 12.48
6.58 12.50
TIME (UBS)
3
30
100
300
1000
Ca(ppa)
348.
334.
345.
336.
349.
Mg(ppm)
6.0
5.2
6.2
5.8
5.0
PCa
2.30
2.32
2.31
2.32
2.31
pH-0.5pCa
4.95
5.24
5.75
5.64
5.25
0.5pCa+pH PO
5.35
5.98
6.95
7.72
6.93
TIHE(HRS)
3
30
100
300
1000
pCa+pHPO
7.60
7.93
8.40
9.27
8.88
3pCa*2pPO 4pCa*pH*3pPO
29.95
30.04
29.96
31.92
31.92
49.88
50.30
50.68
53.51
53.12
10pCa+6pPO *2pOH
107.96
107.64
106.37
112.47
113.26
APPENDIX TABLE 4 (continued)
61
-------
SOIL- 1C
P CONCENTRATION- 12.5 ppa
TIME (UBS)
3
30
100
300
1000
PH
6.00
6.20
6.50
6.90
6.00
P(ppm)
0.320
0.010
0.003
0.006
0.027
PH3P04 PHzP04
8.89 5.01
10.61 6.53
11.47 7.09
11.67 6.89
9.96 6.09
pHPO pPO
6.21 12.54
7.53 13.66
7.79 13.62
7.19 12.61
7.28 13.61
MHB(HRS)
3
30
100
300
1000
Ca(ppn)
339.
348.
342.
327.
340.
Mg(ppm)
5.9
4.8
5.8
5.6
5.6
pCa pH-0.5pCa
2.31 4.84
2.31 5.05
2.31 5.34
2.33 5.74
2.31 4.84
0.5pCa+pH PO
6.17
7.69
8.25
8.05
7.24
TIME(HRS)
3
30
100
300
1000
pCa+pHPO
8.53
9.84
10.10
9.52
9.60
3pCa+2pPO
32.02
34.23
34.17
32.21
34.16
4pCa+pH+3pPO
52.87
56.40
56.60
54.05
56.08
10pCa+6pPO +2pOH
114.36
120.60
119.81
113.16
120.80
62
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APPENDIX TABLE 5
Table 5. Reaction products of applied
identified by X-ray diffraction analysis,
as
Time
(hrs)
SOIL - B
1
3
10
30
100
300
600
1000
SOIL - 0
1
3
10
30
100
300
600
1000
SOIL - AC
1
3
10
30
100
300
600
1000
c-ovvi-v
40
16
—
—
—
—
—
—
40
19
—
—
—
—
—
—
100
100
30
10
—
—
—
—
CaHPO.
4
60
53
37
30
35
40
49
45
60
53
45
27
27
30
35
20
—
70
90
50
55
40
50
CaHPO, -2H 0
(•»*)
31
63
70
65
60
51
55
28
55
73
73
70
65
80
—
—
—
50
45
60
50
63
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/2-77-180
2.
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
DETERMINATION OF KINETICS OF PHOSPHORUS
MINERALIZATION IN SOILS UNDER OXIDIZING CONDITIONS
5. REPORT DATE
August 1977
issnine date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Y. V. Subbarao
Roscoe Ellis, Jr.
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Department of Agronomy
Kansas State University
Manhattan, Kansas 66506
10. PROGRAM ELEMENT NO.
1BC611
11. CONTRACT/GRANT NO.
R803936
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
Final Report
14. SPONSORING AGENCY CODE
EPA/600/15
15. SUPPLEMENTARY NOTES
16. ABSTRACT
In search of a better approach to predict phosphorus movement in soils
from applied wastewaters, reactions of added orthophosphates were studied
in 9 different soils with widely varying physical and chemical properties.
Information obtained on the nature and rate of P reaction will be coupled
with P adsorption data to derive mathematical models for P movement in soils
from applied wastewaters.
Compounds having higher solubility than variscite were formed which
changed to crystalline variscite with time upon adding CaCHaPOOz'^O to
acid soils. Monocalcium phosphate monohydrate in alkaline soils transformed
to relatively insoluble CaHPO^-2H20, CaHPOi,, Ca3(POO2, CaijKPOO 3*2JgH20,
and Ca 10 (OH) 2 (POO 6. The rate of transformation in both acid as well as
alkaline soils was P rate dependent; slower with increased P rates.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Chemical kinetics
Soil chemistry
Physical chemistry
Sewage treatment
Water reclamation
Sorption
Phosphorus kinetics
Solubility products
13-B
02-A
07-D
08-D
3. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (ThisReport/
UNCLASSIFIED
21. NO. OF PAGES
72
20. SECURITY CLASS (Thispage)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (9-73)
64
•& U. S. GOVERNMENT PRINTING OFFICE: 1 977-757-056/65'fO Reg I on No . 5- 1 1
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