United States
Department of
Agriculture
United States
Environmental Protection
Agency
Cooperative States
Research Service
Washington. D.C. 20250
Office of Research
and
Development
Industrial Environmental
Research Laboratory
Cincinnati, Ohio 45268
CSRS-1
EPA-600/7-77-093
August 1977
RECLAMATION OF SURFACE
MINED COAL SPOILS
Interagency
Energy-Environment
Research and Development
Program Report
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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
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The nine series are:
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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
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This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT
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tems. The goal of the Program is to assure the rapid development of domestic
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essary environmental data and control technology. Investigations include analy-
ses of the transport of energy-related pollutants and their health and ecological
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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-600/7-77-093
August 1977
RECLAMATION OF SURFACE MINED COAL SPOILS
by
Richard I. Barnhisel
Kentucky Agricultural Experiment Station
Agronomy Department
University of Kentucky
Lexington, Kentucky 40506
GSRS IAG No. D6-E762
Project Officer
Ronald D. Hill
Resource Extraction and Handling Division
Industrial Environmental Research Laboratory - Cincinnati
Cincinnati, Ohio 45268
This study was conducted in cooperation with the Cooperative
State Research Service, U.S.D.A., Washington, D. C. 20250
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI., OHIO 45268
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DISCLAIMER
This report has been reviewed by the Industrial Environmental Research
Laboratory - Cincinnati, II. SŦ 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 endorse-
ment or recommendation for use.
ll
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FOREWORD
When energy and material resources are extracted, processed,
converted, and used, the" related pollutiohal impacts on our environment
and even on our health often require that new and increasingly more
efficient pollution control methods be used. The Industrial5Environ-
mental Research Laboratory-Cincinnati (lERL-Ci) assists in developing
and demonstrating new and improved methodologies that will meet these
needs both efficiently and economically.
<. ., - I-.,*. -, , ,,-,
Reported here is the results of a study supported cooperatively
by U. S. Department of Agriculture and U. S. Environmental Protection
Agency at the Kentucky Agricultural Experiment Station. A study was
conducted to evaluate several soil treatments of reclaimed coal mines
to improve plant establishment and growth. The results of this work
should provide to the reclamation specialist of a mining company or
control agency additional methods to establish good ground cover to
minimize the environmental problem from surface mining. For further
information contact the Extraction Technology Branch of the Resource
Extraction and Handling Division.
David G. Stephan
Director
Industrial Environmental Research Laboratory
Cincinnati
ill
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ABSTRACT
Field experiments were established in western Kentucky on four
types of surface-mined coal spoils. These areas were selected to
represent the extremes in spoil materials commonly encountered in
reclamation. This report presents evidence that mine spoils may be
successfully reclaimed when proper levels of fertility have been
restored.
With the provision for retaining rainfall on the spoils, yields
of mixed legume-fescue forage exceed 4 metric tons per hectare
(2 T/acre). These yields are equal to or greater than those of
adjacent non-mined land. The advantage of a rough surface created
by ripping of subsoiling was obtained at all levels of applied
phosphorus. The use of a chisel plow or heavy-duty disk produced a
rough micro-relief that also produced significantly greater forage
yields than obtained from smooth graded plots.
It was found that phosphorus and water are more commonly the
limiting factors in obtaining an adequate degree of vegetative
cover and associated forage yield than the acidic nature of spoils.
However, in acidic spoils lime must be incorporated in order to
effectively improve the growing conditions. Downward movement of
lime should not be expected to occur at a rate sufficiently high to
improve the growing conditions of spoils for plants. Acidic spoils
also tend to be much more droughty than adjacent non-acid spoils as the
result of a restricted rooting depth.
IV
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TABLE OF CONTENTS
Page
I. CONCLUSIONS 1
II. RECOMMENDATIONS 3
III. INTRODUCTION 9
IV. METHODS AND MATERIALS 12
GEOLOGICAL DESCRIPTIONS OF RECLAMATION SITES 12
NEUTRAL SHALE SITE 12
SLIGHTLY ACID SHALE SITE 12
ACID SHALE SITE 13
VERY ACID SANDSTONE SITE 14
FIELD EXPERIMENTS 15
Neutral Shale Site . 15
Slightly Acid Shale Site 17
Acid Shale Site 18
Very Acid Sandstone Site 18
x Evaluation of Microrelief 20
LABORATORY METHODS 20
Soil Sample Preparation 20
pH Measurement in Water, KC1 and SMP Buffer
Solutions 21
Phosphorus Analysis . , 21
Potential Acidity 21
Exchangeable Cations: Calcium, Potassium, Magnesium
and Sodium 22
Plant Sample Preparation 22
Chemical Composition of Plants ... 22
V
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Table of Contents (cont'd) Page
V. RESULTS AND DISCUSSION 24
NEUTRAL SHALE SITE 24
Establishment of Vegetative Cover 24
Changes in Chemical Properties of the Spoils . . 26
Forage yield response to phosphorus - tillage
t
treatments 32
SLIGHTLY ACID SHALE SITE 34
Establishment of vegetative cover 34
Changes in chemical properties of the spoils . . 37
Forage response to tillage treatments 41
ACID SHALE SITE 44
Establishment of vegetative cover. . . 44
Changes in chemical properties of the spoils . . 45
Forage response to tillage treatments 49
VERY ACID SANDSTONE SITE 52
Establishment of vegetative cover 52
Changes in chemical properties of the spoils . . 52
VI. REFERENCES 55
VI
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LIST OF TABLES
Page
Table 1. Effect of phosphorus treatments on the survival of
fescue and red clover plants at three months,
averaged across all tillage treatments at the neutral
shale site 25
Table 2. Bray-1 phosphorus levels averaged over all tillage
treatments as affected by phosphorus applications
at the neutral shale site. ...... 27
Table 3. Exchangeable cations and pH measurements averaged
over all tillage and phosphorus treatments at the
neutral shale site 28
Table 4. Changes in phosphorus forms with time as a result of
phosphorus application averaged across all tillage
treatments 30
Table 5. Effect of phosphorus and tillage treatments on forage
yields of fescue - red clover hay at the neutral
shale site ... 33
Table 6. Effect of applied phosphorus on chemical composition
of red clover-fescue forage harvested 17 months after
Ŧ
establishment at the neutral shale site ......... 35
Table 7. Changes in pH following establishment of tillage-
legume treatments in September at the Slightly
Acid Site 38
Table 8. Changes in Bray-1 phosphorus levels following the
establishment of tillage-legume treatments in
September at the Slightly Acid Site 40
vii
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List of Tables (cont'd)
Page
Table 9. Effect of the tillage treatments on fescue-legume
forage yields* for the first harvest (May) at the
slightly acid site 42
Table 10. Effect of the tillage treatments on fescue-legume
forage yields* for the second harvest (August) at
the slightly acid site 43
Table 11. Changes in pH values following establishment of
tillage-legume treatments in September at the
Acid Shale Site 46
Table 12. Changes in Bray-1 phosphorus levels following the
establishment of tillage-legume treatments in September
at the acid shale location 47
Table 13. Effect of the tillage treatments on fescue-legume
forage yields* for the May harvest at the acid shale
site 50
Table 14. Effect of the tillage treatments on fescue-
legume forage yields* for the August harvest at
the acid shale site 51
Table 15. Effect of lime rate and method of incorporation on
pH levels sampled at three depth Increments and
forage yields 33
Vlll
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ACKNOWLEDGEMENTS
This study was conducted cooperatively by the Agronomy Department
with Southwind Coal Mining Co., Peabody Coal Co., and Kentucky
A
Reclamation Association Inc. The cooperating companies assisted by
providing land on which the experiments described were conducted,
technical assistance in planning as well as providing labor in the
establishment of the experimental treatments and their subsequent
evaluation.
The diligent work of Mr.James L. Powell, Reclamation Supervisor,
Peabody Coal Co., Mr. Richard Buddeke, Southwind Coal CQ. and
and Mr. Ben Walcott, KRA is greatfully acknowledged. Without the
assistance of these persons, the field work could not have been
conducted. The completion of this project would not have been
possible without the assistance of Mr. Gary W. Akin and Mr.
Wayne Ebelhar, both of whom are graduate assistants,as well as
several undergraduate assistants.
C. Gran Little served as Project Officer for the Kentucky Agri-
cultural Experiment Station, and Eilif V. Miller coordinated the effort
for the Cooperative State Research Service, USDA.
IX
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I. CONCLUSIONS
A significant forage response to applied phosphorus was obtained
for Ky 31 tall fescue and red clover planted on neutral surface-mined
coal spoils. This response was enhanced on plots that were ripped
or subsoiled. The effect of ripping significantly increased forage
production at all phosphorus levels tested. The ripping improved the
microrelief which resulted in keeping more rainfall on the spoil areas,
hence reduction in runoff should have occurred although this was not
measured. The rough spoil surface temporarily stores water so that
the effect of the poor infiltration property of spoils could be
counteracted. An improved microrelief was obtained by both the chisel
plow and the heavy-duty disk, therefore, these implements may be used
in place of the rippers thus large acreages could be economically
treated. Yields from fescue red clover forage, when ample phosphorus
was applied, equaled those of adjacent non-mined lands.
The acid nature of spoils appears to reduce vegetative cover
indirectly both by the fixation of phosphorus as iron-phosphate and
the restriction of root growth and in effect acid spoils are unusually
droughty. Yields obtained from a slightly acid shale location were
significantly larger than those from an acid shale site. As demon-
strated in earlier research, the acid spoils are more harmful to
legumes than Ky 31 tall fescue.
Both disking or chisel plowing were effective in lime incorporation.
The incorporation of added lime appears to be extremely important and
downward movement below zone of incorporation should be expected to
occur only at a very slow rate.
It is apparent that on acid spoils competition for water between
1
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grasses and legumes may be more critical than on slightly acid or
neutral spoils. The selection of more drought tolerant plant species
may be beneficial on such surface-mined spoils.
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II. RECOMMENDATIONS
An evaluation should be made at each mine site of the potential
spoil materials that could occupy the graded surface. These potential
spoils should be considered with respect to their suitability as a
growing media for the various plant species that could be planted
during revegetationi This information will allow the surface-mine
operator to consider alternative mining practices such as, spoil
placement or segregation versus chemical amendments necessary to
obtain the desired properties of spoils so that a suitable vegetative
cover may be obtained.
Recognition and subsequent correction of several possible
limiting factors will allow reclaimed surface-mined areas to realize
their maximum agricultural potential. Such limitations include:
(1) a general low fertility of spoils with respect to phosphorus,
nitrogen, and possibly potassium; (2) acidic properties both active
and the potential acidity which may be released by the oxidation of
sulfide minerals; and (3) droughty nature of spoil materials including
physical properties as water storage capacity, infiltration and
particle size or textural components. An evaluation of the suitability
of any given spoil material with respect to its chemical properties
may be obtained by submitting samples to testing laboratories (such
as the Kentucky Agricultural Experiment Station) which are equipped
to handle such spoil materials.
The phosphorus fertility status should be determined on all spoil
materials prior to seeding. Spoils may be tested with procedures
commonly used to test soils, however, only limited research is
presently available to determine if the fertilizer rates as recommended
3
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from thest tests are applicable to the reclamation of spoils. Yields
from plots fertilized according to the recommended levels should be
measured over several years inorder to determine if a single
application at seeding will sustain both a vegetative cover and forage
production. Supplemental applications of phosphorus may be needed
with time since spoil tests taken from established plots were much
lower the second growing season.
The nitrogen status of mined spoils should be expected to be nil
as the organic matter levels are essentially zero. Applications of
nitrogen will be necessary to establish a vegetative cover. At least
one legume species should be included in all reclamation plantings.
Care should be taken in applying nitrogen as not to reduce the
effectiveness of the legume to supply nitrogen, in addition, split
applications of nitrogen appears to reduce the competition between
grass and legume species.
The amount of available potassium should be determined for all
spoils. In general, shaly spoils appear to supply adequate amounts
for maximum growth. Based on a limited amount of information, it
appears that sandy spoils may not have adequate potassium levels.
This research project was not conducted over a sufficient amount of
time to evaluate changes in potassium levels for plots in which the
forage produced was removed.
Lime additions should be made based on test results from both
the active acidity (measured by a test such as the SMP buffer method)
and the total potential acidity (oxidation of sulfide minerals), All
lime should be incorporated into the spoils to facilitate as deep
a rooting zone as possible. Field evaluations of these laboratory tests
4
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are needed as both a function of lime rates and time. Recommendations
made from both the SMP buffer and total potential acidity tests were
done with the assumptions commonly used for soils. Therefore, the
assumptions as to reaction rate, lime quality and fineness of grind
should be tested at various lime rates.
An effort to create a rough surface, on a micro-scale, should
be made in the preparation of a site for seeding. This practice
not only reduces runoff and its accompanying erosion, but also
providing more available moisture for utilization by the vegetative
species. Although it was assumed that yield response of the roughest
plots was the result of greater available moisture, this theory
should be tested on small water sheds or with a rainfall simulator.
It is apparent that a mulch will be beneficial in both the
establishment of a vegetative cover and the maintenance of forage
production on surface-mined spoils. The effect of the mulch appeared
to increase the amount of available moisture as well as allow a
significant phosphorus response. These benefits were found on a neu-
tral shale site which was somewhat unexpected. The experimental
design did not allow us to separate the effects of mulch versus
subsoiling since mulch was not applied to the control areas. Subse-
quent testing will be necessary not only on shaly but also the more
droughty sandy spoils.
Since moisture holding capacity and water infiltration of spoils
should be largely a function of spoil type, geologic maps should
serve as a basis of preplanning so that the operator can place the
most desirable materials on the surface. Considerations as to the
chemical properties of the respective geologic formations should have
5
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a precedence over water holding or infiltration considerations. Since
geologic maps are not prepared on a scale to show detail and since
assumptions are made in the mapping process by extending information
from a few rock outcrops to large areas, verification should be made
as to the thickness and other changes in the various geologic
formations as mining takes place.
The plant species used in the reclamation effort should be made
according to the projected agricultural use as well as to their
tolerances to drought or high temperatures, to their ability to grow
at low phosphorus fertility levels and to their possible tolerance to
toxic levels of iron, manganese and aluminum. These three types of
adverse conditions may or may not occur simultaneously on any given
site. For Kentucky climatic conditions, Ky 31 tall fescue provided
both an adequate vegetative cover as well as producing forage yields
equal to those of non-mined land. These results were obtained on
shaly spoils which had lime requirements of less than 30 metric tons
per hectare (13 T/acre). On more acid and/or droughty sandy spoils,
tall fescue did not prove to be successful. On a trial area, a small
plot of common bermudagrass was seeded and although additional testing
is required, it appears that bermudagrass may serve to revegetate
this spoil type.
The suitability of reclaimed surface-mined land for sustained
agricultural production is not known. The effect of removing forage
by animal grazing and the subsequent recycling of nutrients may be
beneficial in the formation of a "soil". Other pasture or range
management practices such as reseeding or renovation, applications of
litrogen and other fertilizers as well as clipping or mowing should be
6
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evaluated on reclaimed areas. Changes in plant species, vegetative
cover, stand density as a result of the above management practices
should be evaluated in field trials.
Areas requiring additional research
Associated with the above recommendations, comments were made
as to areas in which additional research is needed for verification
of these recommendations over longer periods of time. Many of these
gaps in the research findings will be filled with the monitoring
of the established areas associated with this research project but
for others additional field experiments will be required. Based on
the research finding presented in this report the specific areas
requiring additional research are as follows: (1) Burial of acid
shale vs heavy liming, (2) benefits of mulching on various spoil
types, (3) evaluation of tillage and other techniques to provide more
efficient use of available moisture including the evaluation of
micro-climate and the promotion of water infiltration rather than
runoff, (4) evaluation of fertility requirements such as nitrogen,
phosphorus and potassium in order to obtain sustained forage produc-
tion especially as on mined land having a high agricultural potential,
and (5) evaluation mixtures of plant species and management systems
that stimulate natural succession.
In addition, much has been speculated as to the benefits of
top-soiling in reclamation. Most likely there are many areas in the
United States in which top-soiling would be beneficial, but in other
areas, especially in Kentucky, the available topsoil materials may
have physical and chemical properties less desirable than certain
geologic materials, therefore, the assumption that topsoiling is
7
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always better is not valid. The contribution of sediment of this
topsoil material should b,e evaluated especially when it overlies
spoils of contrasting physical properties. The cost-benefit rela-
tionships of topsoiling should be investigated as well as determining
how one should reconstruct a soil to maximize the agricultural
potential of the reclaimed land.
This report covers the findings from one and one half years
of laboratory and field work on a series of selected minespoil sites.
Follow-up research now under way on existing experimental areas
and on new sites will permit further precision of reclamation
recommendations in subsequent reports by the author.
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III. INTRODUCTION
" Considerable acreages of land have been and are being disturbed
by surface mining of coal in the two coal fields of Kentucky. Although
mining techniques are different, similar problems exist in the
reclamation of these spoils from a chemical and physical viewpoint.
The project, as proposed, deals with surface mining in the western
Kentucky coal field.
In Kentucky, progress from demonstrations, field trials, and
research projects have been reported (eg. Berg and Vogel, 1968; Berg
and Vogel, 1973; Curtis, 1971; Vimmerstedt, 1970; and Vogel, 1973).
These have been largely restricted, however, to investigations in
eastern Kentucky and although success has been achieved, only
limited application can be made for western Kentucky. This lack of
application largely resulted from the difference in surface mining
techniques as well as the terrain. In western Kentucky, area mining
is used whereas in eastern Kentucky, surface mining follows the contour.
These two mining techniques result in significant differences in
topography and associated reclamation problems. Area mining used in
western Kentucky results in poorer moisture conditions as the disturbed
area is not buffered by undisturbed regions. The order or priorities
or steps needed with respect to achievement of successful reclamation
are not the same.
Chemical, physical and mineralogical properties of spoils are
highly variable. This variability occurs simultaneously on a macro
and micro scale. Variations with respect to major rock strata are
important in the overall consideration of a reclamation plan but not
any more so than are variations in chemical environment on a small
9
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scale can result in bare or reduced vegetative cover. The presence
of sulfide minerals in particular pyrite and marcasite, associated
with coal deposits potentially may release ions toxic to plant growth
(eq. Barnhisel and Massey, 1969; Berg and May, 1969; Cummins et al.,
1965; Massey, 1972; Massey and Barnhisel, 1972; and Plass and Vogel,
1973). These toxic conditions could explain the lack of consistent
establishment of vegetation on acid spoils.
Although it seems that simple addition of lime to spoils when
acid conditions exist would solve this problem of reclamation,
prediction of lime rates that allow economic solution are not known.
A literature search will reveal that very few replicated experiments
have been conducted for determination of proper lime rates and none in
Kentucky (Funk, 1962; Plass, 1969; Button, 1973; Czapowskyj, 1976).
Although not all spoils are acidic at time of seeding, in the
past, poor vegetation was usually attributed to acidity. Some of
these spoils may have become acid after failure in reestablishment
of vegetation. Such an occurrence was believed to have been the
result of other factors such as lack of phosphorus or other plant
nutrients and the generally droughty nature of spoils. Observations
of spoils in which a vegetative cover was absent reveal an appearance
of a "desert" pavement. Chances for survival and growth of scattered
existing plants under such conditions is extremely poor. These areas
became "moonscapes" and the cause often placed on the wrong thing,
acidity, whereas the lack of available moisture more frequently is the
culprit. This deficiency was further ignored as the result of the
paradoxical conditions associated with a "desert" pavement that being,
an unusually high runoff rate as the result of both poor infiltration
in
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and temporary water storage.
The objectives of this study were: (1) to determine the chemical
and physical properties of surface mined coal spoils and to determine
how these properties affect establishment and survival of vegetative
cover; (2) to develop a method of tillage compatible with the physical
properties of spoils as to produce a stable microrelief which allows
increased infiltration of rainfall and its subsequent utilization by
vegetation, and (3) to evaluate, in field experiments, the lime rates
predicted from both the standard SMP buffer pH method and a hydrogen
peroxide oxidation potential total acidity test.
Objectives presented above were evaluated either separately or
in combinations at four locations. These sites were selected to give
a range of chemical and physical conditions typical of spoils found
in the western Kentucky coal field. Data from a preliminary study
which had been established in anticipation of obtaining the present
grant are also included in this report.
11
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IV. METHODS AND MATERIALS
GEOLOGICAL DESCRIPTIONS OF RECLAMATION SITES
NEUTRAL SHALE SITE
Spoils consisted of overburden from the Elm Lick coal bed
(sometimes referred to as No. 6 or the Dunbar coal bed) of lower
Pennsylvanian Age. The coal bed ranges in thickness up to 1 meter
with occasionally two rider seams of 0.5 meter thickness each. Spoils
were comprised of gray, weakly cemented shale and siltstone rock
fragments. These materials were relatively hard when first exposed
but within six months decomposed to a material having a texture of
loam with varying amounts of thin (0.5 to 1 cm) rock fragments of
weakly cemented sandstone. The weathered spoils generally have a
neutral pH with little or no sulfide minerals, i.e. zero potential
acidity.where the rider coal seams are thin, or the ash content
high, this coal is incorporated into the spoils during mining and
when this occurs the resulting spoils may have a slightly acid pH.
Specific chemical and physical data are presented later.
The field study was located in Ohio Co., Geologic Map of the
Rosine Quadrangle, GQ-928 with approximate coordinates of 37° 24'
north latitude and 86° 41' 30" west longitude. The site has an
approximate elevation of 200 meters MSL with a slope of 6 percent and
a southwest aspect.
SLIGHTLY ACID SHALE SITE
Spoils at this location were derived from overburden from the same
coal bed described above. The proportion of carbonaceous shale imme-
diately above the Elm Lick coal was thicker at this location and
accounts for its slightly more acid pH. The greater frequency and
12
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thickness of the weakly cemented sandstone strata also resulted in
a more rocky spoil. In addition, the shale member contained nodules
of hard clay-ironstone that when weathered have a red, purplish-red
or dark brown color.
The field study was located at approximate coordinates of 37°
25' north latitude, 86° 47' west longitude. The elevation is
approximately 170 meter MSL with a slope of 2 percent and a eastern
aspect.
ACID SHALE SITE
Spoils at this location were derived from the overburden
associated with the No's 9, 11 and 13 coal beds of middle and upper
Pennsylvanian Age. As the result of inversion during mining, the
major proportion of the spoil materials is probably derived from
strata above the No. 9 coal bed. These strata contain siltstone,
shale and sandstone beds. The shale immediately above the coal is
highly carbonaceous and flaggy with a pyritic or sulfide bearing
mineral that contributes to the acidic nature of these spoils.
Most of this shaly material is buried during mining but when incor-
porated into the spoils, zones of extremely acidic spoils occur in
erratic shapes when graded. The sandstone materials contain some
pyrite that upon weathering contributes to the acidic nature of the
spoil. Overburden above the No. 11 and 13 coal beds consist of
shale, sandstone and limestone beds. The contribution of these
materials to the spoils if uniformly mixed would be less than
one-fourth of the total thickness. Limestone rock fragments when
present in the spoil tend to be large, hard and ineffective in
neutralizing the acid associated with No. 9 overburden.
13
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The study site is located at approximate coordinates of 37° 17'
north latitude, 86° 57' 30" west longitude. The site has an elevation
*
of approximately 120 meters MSL with a slope of 3 percent and a north
aspect.
VERY ACID SANDSTONE SITE
Spoils at this location were derived from overburden associated
with the No.'s 11 and 12 coal. The rock strata are composed of
medium grain sandstone above the No. 12 that weathers to a bright-
orange, brown color. This sandstone contains sulfide minerals which,
when oxidized, results in an extremely acid spoil. Separation between
the No. 11 and 12 coal beds is usually less than 10 meters and
consists of limestone, shale and underclay. This material has been
randomly mixed with the sandstone overburden. The sandstone portion
makes up more than 80 percent of the spoil materials. The limestone
fragments remaining are hard massive rock of boulder size whereas
the shale and underclay materials are blended in with the sandstone
upon grading.
This study site is located at approximate coordinates of 37° 17'
30" north latitude and 87° 14' 30" west longitude. The elevation
is about 135 meters MSL and with a slope of 5 percent and a southerly
aspect.
14
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FIELD EXPERIMENTS
Neutral Shale Site. All experimental treatments described
below were established in the spring planting season (March). The
experiment described below was established to answer questions
raised by objectives 1 and 2 of section III. This site was
located on land mined by the Southwind Coal Mining Co. Inc.
A randomized split-plot experimental design with six replica-
tions was employed to test the effect of site preparation and
phosphorus fertilizer on the establishment of red clover
(Trifolium pratense L.) and Kentucky 31 tall fescue (Festuca
arundinaoea) as a vegetative cover. The four tillage-site
preparation treatments were performed on the contour, with a plot
size of 6.1 x 20.1 meters (20 x 66 feet). The preparation treatments
were the whole plots and included: (1) smooth graded and disked one
time with a tractor-mounted disk; (2) smooth graded and disked
1
three times with the same disk: (3) smooth graded, disked three
times, and ripped (or subsoiled) with two ripper spikes mounted
on the tool bar of a D-9 Caterpillar tractor; and (4) smooth graded,
disked three times, ripped (or subsoiled) and a mulch equivalent
to 1680 kg fescue hay per hectare (1500 Ibs/acre) was applied.
The rippers used in treatments (3) and (4) were operated at a depth
of 60 cm (24 in) and the tractor made two passes per plot so that
the ripped channels were spaced approximately 1.5 meters (5 feet)
apart.
15
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Each of the whole plots was divided into three subplots 6.1 x
6.7 meters (20 x 22 feet) for the various phosphorus treatments.
The phosphorus fertilizer (concentrated superphosphate, i.e. 0-46-0)
was applied at the following rates: (a) 0 kg P/ha; (b) 84 kg P/ha
(75 Ib P/acre); and (c) 168 kg P/ha (150 Ib P/acre).
Nitrogen was uniformly applied as ammonium nitrate at a rate of
28 kg N/ha (25 Ib N/acre) at seeding. An additional 28 kg N/ha was
applied both in the fall and the following spring.
The seeding rates for fescue and red clover was 44.8 and 13.4
kg/ha (40 and 12 Ib/acre), respectively. All seed and fertilizers
were applied to the surface after the tillage treatments were
established.
Spoil samples were collected prior to establishment of the
various phosphorus-tillage treatments, two months following estab-
lishment from each sub-plot. The following year, spoil samples
were collected from each subplot in the spring and following the
second forage harvest in August. Each sample was a composite of
two subsamples taken from the upper 15 cm of each plot.
Forage samples were not collected the first or establishment
year. The following May, forage harvests were made from randomly
chosen areas from each of the subplots with a,rotary lawn mower.
All harvests were made perpendicular to the travel of the tillage
implements. The fresh plant weight was determined in the field and
subsamples were taken from each subplot to determine both moisture
and plant chemical composition. These plant samples were placed in
plastic bags, sealed, and frozen using dry ice. The plant samples
were maintained frozen until they were placed in an oven for moisture
16
-------
analysis.
Slightly Acid Shale Site. The use of rippers,as described in
the above experiment,produced an apparent stable microrelief, however,
two factors may prevent its acceptance: (a) the use of a large Cater-
pillar tractor would be costly and (b) large rock are brought to
the surface by this tillage practice and the surface no longer
satisfied the smooth grading requirement. Therefore the experiment
described below was established as an alternative. All treatments
were established in the fall seeding season (September) as it is at
this time the majority of reclamation plantings are made in western
Kentucky. Objectives numbers one and two of Section III, page 5, are
associated with this experiment.
The site on which the following experiment was located was mined
by the Southwind Coal Mining Co. Inc. A randomized split-plot
experimental design with four replications was used in which the
whole plots were three tillage treatments (1) smooth graded; (2)
disked with large heavy-duty pull-type wheel disk; and (3) chisel
plowed. These three treatments are given above in order of increased
roughness. Superimposed on each of the tillage treatments as
subplots were various legume species seeded with Kentucky 31 tall
fescue (Festuoa arundinacea). These species included: red clover
(Trifolium pratense L.)j white clover (Trifolium repens L.);
crownvetch (Coronilla vca?ia L.); yellow sweetclover (Melilotus
officianalus)j alfalfa (Medicago sativa L.); sericea lespedeza
(Lespedeza ouneata); and birdsfoot trefoil (Lotus covnioulatus L.).
All subplots were 5 x 10 meters (16.5 x 33 ft) and the various plant
species were seeded with hand spreaders on the spoil surface after
17
-------
the tillage was performed. The fescue was seeded uniformly over the
entire area at a rate of 40 kg/ha (35 Ib/A). The legumes were
seeded at rates recommended for agricultural soils (See Kentucky
Agr. Exp. Sta. publication AGR-18 for recommended seeding rates).
Uniform rates of phosphorus, 84 kg P/ha (75 Ib P/acre), and nitrogen,
28 kg N/ha (25 Ib N/acre), were applied at seeding to entire area.
An additional application of nitrogen, at the above rate, was
applied in the following spring.
Sampling techniques with respect to forage and spoil samples
were the same as those described for the previous study.
Acid Shale Site. The identical experiment as described above
(b) Slightly Acid Shale Location, was also established on land
mined by Peabody Coal Co. Experimental objectives numbers one and
two are also applied to the study of this location. At the time of
establishment of this experiment, the pH of the spoils was not below
the minimum pH level required by the Division of Reclamation, hence,
Ag lime was not applied. The following summer>and after the second
forage harvestj the pH had dropped below these standards and Ag lime
was applied at a rate of 15 metric tons/ha (7 t/acre) without
incorporation.
Very Acid Sandstone Site. All experimental treatments described
below were established in the fall planting season (September)
on land mined by Peabody Coal Co. This experiment was designed to
answer questions raised by objectives 1, 2, and 3 of section III.
Previous experience by coal companies in the area indicated that very
large lime rates would be required. Two lime rates were chosen,
67.2 metric tons/ha (30 t/acre) and 134.4 metric tons/ha (60 t/acre)
18
-------
based on the SMP buffer pH method. Unfortunately, after the site
was chosen, it was determined that essentially all the sulfide
minerals had been already oxidized and hence the SMP buffer lime
requirement and potential acidity lime requirement were the same.
In addition to the two lime rates, two methods of lime incorporation
were used, disking with a heavy-duty wheel disk and with a chisel
plow. These incorporation methods were compared with surface applied
lime. A randomized block experimental design was used with four
replications and all plots were 10 by 10 meters (33 x 33 feet).
Immediately after the lime treatments were established, the entire
area was seeded to Ky 31 tall fescue at 40 kg/ha and a mixture
legume species (alfalfa, red clover, crownvetch, birdsfoot trefoil
and sericea lespedeza). The rate of each legume used was one-fifth
that of the recommended rates for agricultural soils. On one of
the incorporation treatments, the seeding of the legumes was delayed
until March. This resulted in the following ten combinations of
lime incorporation - seeding treatments: (1) 67.2 mt/ha (30 T/acre)
of Ag lime incorporated by disking; (2) 134.4 mt/ha (60 T/acre)
disked; (3) 67.2 mt/ha incorporated by chisel plowing: (4) 134.4 mt/ha
chisel plowed; (5) 67.2 mt/ha incorporated by disking but legume
seeded in following spring; (6) 134.4 mt/ha disked and delayed legume
seeding; (7) 33.6 mt/ha incorporated by chisel plowing, then 33.6
mt/ha applied to the surface; (8) 67.2 mt/ha incorporated by chisel
plowing, then 67.2 mt/ha applied on the surface; (9) 67.2 mt/ha
applied to freshly smooth graded plots without incorporation; and
(10) 134.4 mt/ha of Ag lime applied to the surface. All lime was
applied by a spreader truck and a border zone around each plots was
19
-------
rates.
Forage samples were collected by the technique described in
section a of the above. However, because of the poor vegetative
growth and subsequent yields, only one forage harvest was made.
Spoil samples were taken as described above except the last sampling,
one year after establishment, were increment samples. These were col-
lected from 0-5, 5-10 and 10-15 cm depths with sufficient numbers of
probings to yield at least 250 gram. This usually required 10 such
subsamples and these were taken randomly over the 10 x 10 meter
area.
Evaluation of Microrelief. Changes in the microrelief created
by the rippers were evaluated with a device constructed similar to
that described by Curtis and Cole, 1972. A 1 x 1.5 meter piece
of peg-board was framed with aluminum angle and holes drilled at
2.5 cm intervals in this angle frame so that 1 meter copper coated
steel welding rods would freely slide up and down. On each end of
the peg-board was secured a small section of capped, 7.6 cm pipe.
Steel fence posts were driven into the spoils so that the peg-
board frame could be slopped over the permanent reference stakes.
Once the peg-board was in place, the steel rods were lowered as to
touch the spoil surface. The micro-relief of the spoil surface was
recorded one week after establishment as well as at two and four
months.
LABORATORY METHODS
t
Spoil Sample Preparation. All spoil samples collected in the
field were air dried. They were ground to pass a 2 mm screen with
a mechanical grinder and stored in plastic bags until analyzed.
20
-------
pH Measurement in Water, KC1 and SMP Buffer Solutions.
Appropriate amounts of each spoil sample was weighed into 100 ml
plastic beakers so that a one-to-one solid:liquid ratio was obtained
in the case of H00 and IN KC1 and a 1:2 ratio for the SMP buffer. The
Ģ.
SMP buffer was made up according to the directions of Shoemaker
et^ al., 1961. The pH's of the samples were determined after 30
minutes, with occasional stirring, using a Corning model 7 pH meter
equipped with glass and calomel electrodes.
Phosphorus Analysis. All spoil samples were tested for
"available" phosphorus using a method adapted from Bray and Kurtz,
1945 often referred to as the "Bray-1 method" Spoil samples
collected from the neutral shale experimental site in which various
phosphorus rates had been applied were subjected to the phosphorus
fractionation procedure proposed by Chang and Jackson, 1957. This
method partitions the total phosphorus into four components: (1)
"available" or ammonium chloride extractable phosphorus; (2) aluminum
phosphate; (3) iron phosphate; and (4) calcium phosphate.
Potential Acidity. The potential acidity of selected samples
from each experimental location were analyzed by a hydrogen perioxide
oxidation technique. Briefly this involves finely grinding the
sample to a "flour", oven drying, and weighing a 2.0000 g sample
into a tall form, 500 ml beaker. Successive 10 ml additions of 30%
H009 was added until rapid oxidation reaction does not take place.
Supplemental heating may be needed to insure that the sulfide
oxidation reaction takes place. After the reaction is completed,
the acid released is titrated to neutrality with standardized NaOH.
21
-------
Exchangeable Cations: Calcium, Potassium, Magnesium and Sodium.
Exchangeable cations of selected spoil samples were determined by the
neutral normal, ammonium acetate method. Briefly this method
includes extraction of 10 g samples with successive small portions
of neutral N NH/OAc using a Buchrier funnel until 100 ml volume is
obtained. The displaced Ca, K and Na was determined with a Technicon
flame photometer and Mg with a Varian atomic absorption instrument.
Plant Sample Preparation. Forage samples collected in the
field were maintained below freezing temperatures until moisture
analyses could be determined. The fresh moist weights were determined
and the samples were placed in an oven maintained at 70°C. After
drying, the oven-dry weight was determined, samples were ground to
pass a 40 mesh screen with a Wiley mill. All ground samples were
stored in sealed plastic bags until further analyses at which time
they were redried at 70°C and remixed before subsamples were
withdrawn.
Chemical Composition of Plants. Calcium, magnesium, potassium,
phosphorus, manganese and iron was determined in all plant samples
from solutions prepared by the wet-ashing technique. In this method,
the organic matter is removed by oxidation in a nitric-perchloric
acid solution. This acid is evaporated to dryness and the remaining
salts are dissolved in N HC1. Calcium and K were determined by flame
photometry, phosphorus by a molybdate blue method. The Mg, Mn and
Fe concentrations of the HC1 solution were determined with an atomic
absorption instrument.
Total nitrogen was determined on forage samples taken from the
neutral shale location by the Kjeldhal method. Nitrogen determinations.
22
-------
were not made on the plant samples from the other experimental
locations.
23
-------
V. RESULTS AND DISCUSSION
NEUTRAL SHALE SITE
Establishment of Vegetative Cover; A uniform plant stand for
both red clover and fescue was established on all plots. These
observations were made after three weeks by counting the numbers
2
of fescue and red clover seedlings in three randomly chosen 0.6 m
area from each subplot.
Visual observations made in the field at three months indicated
that the size of both red clover and fescue plants on plots that were
ripped were larger than the disked plots. However, when plant stand
counts were analyzed, there were no statistically significant differ-
ences among any of the four site preparation tillage treatments nor
were there significant interactions among the tillage and phosphorus
treatments. ^/
When the phosphorus fertilizer treatments were averaged over all
tillage treatments, a significant difference was found and these
data are summarized in Table 1. The 84 and 168 kg P/ha treatments
had a significantly greater number of both fescue and red clover
plants than those found on plots receiving no phosphorus. The
differences in plant stands between the 84 and 168 kg/ha phospohrus
treatments were not significant.
In general, seedlings surviving on the zero phosphorus treatment
were experiencing serious phosphorus deficiency symptoms. Subsequent
stand counts were not made due to the difficulty in obtaining
accurate numbers as the result of larger plant size and the tillering
of fescue. It is believed that had data been collected that it would
have paralleled that reported in Table 1 with one exception. On zero
24
-------
Table 1. Effect of phosphorus treatments on the survival of fescue
and red clover plants at three months, averaged across
all tillage treatments at the neutral shale site.
Phosphorus
Applied
kg/ha
0
84
168
LSD.05
LSD.01
Ky 31
Fescue
255
378
372
28
38
Red
Clover
2
70
113
123
17
23
Total
Plants
225
491
495
42
55
25
-------
phosphorus plots, essentially all the red clover plants.died and -,;
the stand of fescue thinned.- -There'were scattered sweet clover
seedlings observed on some of the zero fescue plots. This plant
species was later determined to have come from a contamination in the
red clover seed used.
Changes in Chemical Properties of the Spoils; The stand counts
indicated that there was a vegetative response to the applied
phosphorus. The availability of phosphorus is measured by Bray-1
phosphorus tests dramatically illustrates the effect of these
phosphorus treatments and these data are presented in Table 2.
These phosphorus values in Table 2 have been averaged across all
tillage treatments since there were no significant interactions
between these two experimental variables nor differences in phosphorus
level as the result of tillage treatment. It is apparent that
although the addition of phosphorus raised the available phosphorus
well above required levels for establishment, the Bray-1 phosphorus
was much lower the second growing season. The reduction in the
levels of available phosphorus is most likely the result of its
fixation into chemically bound non-available forms. Any phosphorus
removed as the result of plant harvests would not significantly
contribute to this reduction in Bray-1 phosphorus levels. If phos-
phorus levels continue to decline, the levels may not be sufficient
to maintain adequate vegetative cover and/or yields would be expected
to decline.
Data for the pH measured in both water and KC1 and exchangeable
cations are presented in Table 3. These average values have been
presented since there were no significant differences as the result
26
-------
greater than the ripped treatment. At only the highest phosphorus
treatment was the ripped and mulched treatment greater than the
disked Ix treatment. In addition, the ripped treatment was not
significantly greater than the disked Ix treatment at any of the three
phosphorus treatments.
When the phosphorus treatment means were subjected to statistical
analyses (data not shown as such), a significant response (LSD 1% level)
was obtained between each phosphorus treatments. A similar comparison
made for tillage treatment means revealed that there was no significant
difference between the (disked Ix) versus (3x) treatments nor between
the (ripped) and (ripped with mulch) treatments, the (ripped and
mulched) treatment was greater than both disking treatments at 1% level
and at the same level of significance, the (ripped) treatment was
greater than (disked 3x) treatment. However, ripped alone was not
larger than disking one time.
The chemical composition data of harvested forage are presented
in Table 6. These values have been averaged across all tillage treat-
ments. Only one of these components was significantly related to
the applied phosphorus, that being percent iron, which decreased with
the first level of applied phosphorus. Levels of Mg also tended to be
less as phosphorus was increased whereas, percentages of P, K and Mn,
N and Ca tended to remain constant or rise slightly.
SLIGHTLY ACID SHALE SITE
Establishment of vegetative cover. After the site was prepared
and seeded in September, little rainfall occurred for about three weeks.
This may have had an eventual effect on the legume stand. By mid-
October, the effect of the tillage treatments were quite evident.
27
-------
Table 2. Bray-1 phosphorus levels averaged over all tillage treat-
ments as affected by phosphorus applications at the neutral
shale site.
Time following
establishment
0 (Check)
2 months
13 months
20 months
0
t
2
4
2
2
Applied Phosphorus
84 kg/ha
_ I,,, 13/1,0
2
64
37
31
168 kg/ ha
2
184
74
68
U.S EPA Headquarters
Mail code 3404T
1200 Pennsylvania Avenue NW
Washington, DC 20460
202-566-0556
28
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Table 3. Exchangeable cations and pH measurements averaged over all
tillage and phosphorus treatments-'at the8neutral shale
site.
Time following
establishment
PH
H00 KC1
Exchangeable Cations
Ca Mg K
Na
______ meq/100 g - - - - -
0 (Check) 7.16 7.01 3.40 4.59 0.17 0.15
2 months 7.03 6.76 3.10 4.35 0.19 0.39
13 months 7.40 6.74 3.21 3.38 0.23 0.05
20 months 7.55 6.78 3.61 3.85 0.25 0.04
29
-------
of the imposed phosphorus and tillage treatments on these chemical
properties. From the data, it appeared that there was a small increase
in pH following establishment of the experimental treatments. The
drop in pH at 2 months is most likely the result of sampling as
the initial pH values, eq. 7.16, is the mean of six observations
made from a composite sample from each of the six replications,
whereas, all other values represent means from 72 observations. The
trends in the levels for exchangeable cations are somewhat erratic
with the exception of potassium which tends to increase with time.
This small increase may be the result of physical and/or chemical
weathering of the micaeous shale that is a major component of these
spoils, however, it does represent an equivalent increase in
available potassium of about 70 kg/ha. According to test levels,
the available potassium has increased from the low to medium test
range. In soils, it is uncommon to find exchangeable Mg levels
that exceed Ca, but from a plant nutrition point of view, the test
levels of both of these cations are in the acceptable range.
Data illustrating the effect of phosphorus applications on the
phosphorus forms as extracted by the method proposed by Chang and
Jackson, 1957, are given in Table 4. It is apparent that the initial
levels of H^O-soluble and aluminum phosphorus forms are rather low.
All of the l^O-P forms would be available to plants and a small un-
known proportion of the Al-P form. These levels are compatible with
those given in Table 1 for Bray-1 extractable phosphorus. The influ-
ence of the 84 and 168 kg/ha addition of phosphorus had on the levels
of each phosphorus form is quite evident. Large increases at 2 months
for both Al-P and Fe-P reflect these applications. Only a small change
30
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Table 4. Changes in phosphorus forms with time as a result of phos-
phorus application averaged across all tillage treatments.
1' ~ '
Time Following
Establishment
Phosphorus
Applied
H20-P
Phosphorus Form Total
Al-P Fe-P Ca-P P
months
0
2
13
0
0
84
168
0
84
168
9.6
4.2
9.2
35.0
4.1
6.3
11.8
kg/ha
44.9 46.8 495.9 597.2
27.4 63.2 525.6 620.4
164.5 170.2 557.4 902.3
321.2 229.0 563.7 1148.9
22.8 123.3 588.1 738.3
131.4 231.5 653.7 1022.9
217.6 265.6 605.6 1100.6
31
-------
in the most insoluble form was found at 2 months. At 13 months
following establishment of the treatments, the levels of Al-P decreased
whereas Fe-P and Ca-P experienced increases. The reductions in both
H20-P and Al-P are most likely the result of at least two factors: (1)
conversion of these forms to the more insoluble Fe-P and Ca-P and (2)
the removal of phosphorus by the plants growing on these areas. It
should be noted that the total of all of these forms for each level
of phosphorus applied does not remain constant with time as theory
&
would predict. In addition, the difference between the totals as the
result of added phosphorus does not equal that applied. Both of these
discrepancies may be the result of at least two factors. The first
being, the original method proposed that total phosphorus was to be
determined by total dissolution of the sample and this was not done
due to the laborous procedure required. There are phosphorus forms
other than those four forms presented in Table 4. These additional
forms are often grouped into a form called "occluded" phosphorus
that are not extracted because they are covered by insoluble compounds
or otherwise do not physically come in contact with the extracting
solution. These occluded phosphorus forms may become uncovered as
the result of weathering and hence the apparent total phosphorus may
increase with time. Similarly, under other conditions, the extracted
phosphorus may be reduced by covering otherwise extractable phosphorus
by iron oxides, etc. The second factor that could explain the apparent
abnormalities in the phosphorus sum, with time and between rates of
addition, is sampling errors in the field. Movement of spoils and
phosphorus into depressions created by the tillage treatments could
result in a phosphorus concentrating effect. However, since variations
32
-------
in total phosphorus were independent of tillage treatment, this second
explanation is less likely than-the first. s.o jiissuaxidsiss gKl
Forage yield response to phosphorus - tillage treatments. There
were significant differences in forage yields as the result of the
imposed treatments. The yield data are summarized in Table 5. The
LSD's for both the 5 and 1% levels of significance are given at the
bottom of Table 5. The following statements can be made concerning
the comparisons of yields from various treatment combinations. For
all four tillage treatments, the addition of 84 kg/ha of phosphorus
*
resulted in a highly significant increase in forage yield. The,
further addition of phosphorus did not result in a significantly
greater yield for the disked plots but significantly greater yields
were obtained fromripped plots. The apparent explanation for this
yield response was related to the available moisture in that, for the
disked treatments (either Ix or 3x), water was limiting the expression
of phosphorus on yield. The ripping increased available water and thus
allowed a phosphorus response. Even for these ripped plots, water may
have been limiting to a degree on some plots and thus the yield
response was only significant at the 5 percent level.
Comparison of tillage treatments reveal that even though disking
3x produced lower yields, they were not significantly lower at any
of the three phosphorus rates. Apparently, disking three times produced
a smoother surface following establishment than only one disking.
Comparisons between yield data from the (disked 3x, ripped and mulched)
treatment with the (disked 3x) treatment the former was significantly
higher at all three phosphorus levels. However, at none of the
ŧ-
phosphorus levels was the ripped and mulched treatment significantly
33
-------
Table 5. Effect of phosphorus and tillage treatments on forage yields
3 * of fescue - red clover hay at the neutral shale site.
Tillage
Treatment
Disked Ix
Disked 3x
Disked 3x, ripped
Disked 3x, ripped,
mulched
0 kg/ ha
347
124
465
1355
Applied Phosphorus
84 kg/ha
2298
1616
2902
3263
168 kg/ha
3040
2239
3859
4268
*Total yield of two harvests, weights adjusted to 10 percent moisture.
LSD Q,J between phosphorus trts. for any specific tillage trt. = 816
LSD Q, between phosphorus trts. for any specific tillage trt. = 1092
LSD
Q5 between tillage trts. for any specific P trt. = 1104
LSD
between tillage trts. for any specific P trt
1499
-------
Table 6. Effect of applied phosphorus on chemical composition of
red clover-fescue forage ..harvested 17 months after estab-
- * ':" ! 1,3 -- 9Lr:.)R^:
lishment at the neutral shale site.
Phosphorus Chemical Compaonent
Applied P N Ca Mg K Fe Mn
kg/ha %
0 0.08 1.37 0.75 0.34 1.20 0.223 0.023
84 0.08 1.28 0.75 0.32 1.29 0.041 0.038
168 0.11 1.37 0.69 0.31 1.36 0.039 0.040
35
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Fexcue growth was prominent in the depressions left by the chisel
plowing treatment giving an effect that appeared as if the area had
been drilled with a grain drill. The plant height of fescue in the
chiseled treatment was at least three times greater than the other two
treatments. The disked treatment had a more uniform looking vegetative
cover than the smooth graded treatment but the plant size on these two
treatments were similar. Although density of the stand on the disked
treatment was at least two fold better than the smooth graded plots,
in both cases plants occurred only in micro-depressions. For
smooth graded plots, the depressions were the result of indentations
caused by rocks being pressed into the spoils when the area was
"back bladed." The disk used at this site was a conventional form type
wheel disk and a greater difference between the disked treatment and the
chiseled treatment was apparent here than was observed for the acid
site prepared with a heavy-duty wheel disk.
By the following April, the apparent effect of the tillage
treatments was less pronounced and only with close insepction could
one tell the location of any particular treatment. At this time, the
plant height was the same on all three tillage treatments. However,
it appeared that stand density was greatest on the chiseled treatment,
followed by the disked and then the smooth graded treatments. Plant
stand measurements were independent of the size and tillering nature
of fescue, which dominated the stand.
Observations were made with respect to the survival of each
legume species. A reasonably good stand of alfalfa and birdsfoot
trefoil was obtained on all plots to which it was seeded regardless
of tillage treatments. In general, it appeared that a greater size
36
-------
of plants occurred on chiseled plots although measurements were not
actually taken. An average to poor stand was obtained for red clover,
white clover and sweet clover. The stands on chiseled plots were
perhaps somewhat better than the disked and smooth graded plots on two
of the four replications. Although scattered crownvetch plants were
observed in the fall on all plots, virtually none of them survived
the winter. Those plots on which crownvetch did survive included the
chiseled and disked treatments of one replication and the chiseled
plot of two of the remaining three replications. By fall or one year
after establishment, and particularly after harvesting, all of these
crownvetch plants had died. There was no evidence of any sericea
lespedeza plants in any of the tillage treatments.
Changes in chemical properties of the spoils. The data for the
pH values measured in water, KC1 and the SMP buffer solutions are
given in Table 7. These data were averaged across all tillage and
legume treatments since there was no significant difference as the
result of these variables. It was observed that the tUO pH values
were only slightly greater than the pH value necessary for meeting
5.5 pH value the requirment set by Division of Reclamation. Loss of
the legume species from the stand at this location may have been the
result of these marginal pH's. However, the lime requirement based on
SMP buffer values would not indicate large lime needs. Only one value
approaches the pH of 6.7 below which, lime is usually recommended.
The mean pH values represented in Table 7 were derived from
individual measurements from each of the 96 subplots some of which
were sufficiently acid to require as much as 10 metric tons/ha
whereas others had an alkaline pH.
57
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Table 7. Changes in pH following establishment of tillage-legume
in-.September at the Slightly Acid Site.
Time after
establishment
in months
0
1
8
13
H20
5.6
5.6
5.8
5.6
pH measured in
KC1
5.0
5.1
5.0
4.8
SMP buffer
7.3
7.2
6.8
7.1
38
-------
Table 8. Changes in Bray-1 phosphorus levels following the
establishment of tillage-legume treatmentsin September at
the Slightly Acid Site.
Time after
establishment
in months
0*
1
8
13
Chiseled
4
53
21
20
Tillage Treatment
Disked Smooth Graded
\eol\\ft
4 4
63 49
48 37
29 30
*Sampled prior to applying 84 kg/ha of phosphorus.
39
-------
Changes in available phosphorus as measured by the Bray-1 method
are given in Table 8. Initially,* the phosphorus level was very low.
The addition of 84 kg/ha of phosphorus resulted in a significant
increase in available phosphorus. The reductions of Bray-1 phosphorus
levels at 8 and 13 months were observed. This reduction was the result
of at least two factors (a) formation of iron and aluminum phosphate
compounds which are not extracted by the Bray-1 method or (b) the
result of the fescue-legume vegetation reducing phosphorus levels as the
result of plant uptake. There was a trend for the chiseled plots to
be lower than either the disked or smooth graded plots.
Spoil samples were subjected to neutral normal ammonium acetate
extraction to evaluate levels of exchangeable Ca, Mg, K and Na.
These data are not presented as there were no significant differences
between any of the tillage and/or legume species treatments. All
levels of these cations were at an acceptable level for plant growth.
The level of potassium was in the medium range and perhaps the yields
from the legume treatments could have been higher had potassium
supply been increased.
40
-------
Forage response to tillage treatments. Two harvests were made
from the various legume-tillage treatments, the first in May and the
other in August. Data from these harvests are presented in Tables 9
and 10, respectively. All of the yield values were adjusted to 10
percent moisture for cured hay.
Comparisons made for yields between legumes of any tillage
treatment are probably not valid due to the variability in legume
stands. Comparisons of yields between tillage treatments for any
legume are'valid in the case of alfalfa, birdsfoot trefoil and red
clover and of these three, only the red clover yield from the chiseled
treatment was significantly greater than the red clover yield from
the smooth graded treatment. Some of the other species also approached
being significant of the 5% level but since the legume stands were poor
or non-existent, these differences really represent response of fescue
to the tillage treatment. In addition, when all legume treatments were
averaged for each tillage treatment, the yield from the chiseled
treatment was greater than the smooth graded plot at the 5 percent
level of significance.
Comparisons of yield data from the second harvest indicate that
the overall effect of tillage no longer produced a significant
difference between chiseled and the smooth graded treatments. The
yield of the red clover-fescue chiseled treatment was greater than
both disked and smooth graded treatments. All other tillage treatments
within a legume were not significantly different.
41
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Table 9. Effect of the tillage treatments on fescue-legume forage
*
,,t yields* for the first harvest (May) at the slightly acid
site.
Legume-Ky 31 Fescue
Mixture
Alfalfa
Birdsfoot Trefoil
Red Clover
White Clover
Sweet Clover
Crownvetch
Sericia Lespedeza
Interstate S. Lespedeza
Mean - all legumes
Chiseled
2258
3010
3265
2688
3048
3464
2833
2013
2822
Tillage Treatment
Disked
1802
2576
2585
2134
2562
2207
2049
1976
2236
Smooth Graded
1975
1995
1640'
2495
2173
2171
1630
1560
1955
*Yields adjusted to 10 percent moisture.
LSD QC for tillage treatment means is 702 kg/ha.
42
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Table 10. Effect of the tillage treatments on fescue-legume forage
yields* for the second harvest (August) at the slightly
acid site.
Legume-Ky 31 Fescue
Mixture
Alfalfa
Birdsfoot Trefoil
Red Clover
White Clover
Sweet Clover
Crownvetch
Sericea Lespedeza
Interstate S. Lespedeza
Mean - all legumes
Chiseled
1113
1063
1857
662
943
1055
353
616
992
Tillage Treatment
Disked
Jvg/ lid -
944
558
712
274
498
493
592
273
542
Smooth Graded
652
450
410
1068
666
443
321
248
531
*Yields adjusted to 10 percent moisture.
LSD 05 for tillage treatment means is 710 kg/ha.
43
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ACID SHALE SITE
Establishment of vegetative cover. A good stand of Ky 31 tall
fescue was obtained on all tillage treatments. The density and plant
height at any given time during the fall months was superior at this
location as compared to the slightly acid shale site. Although both
locations were seeded the same day, a rain storm passed over this
acid site that by-passed the other location. This not only had the
effect of causing a earlier emergence but the differences in plant
height as a result of tillage treatment was less pronounced. Essen-
tially there was no difference in plant size between the disked and
chiseled treatments but both were somewhat better than the smooth
graded treatment. The rainfall factor may explain part of the
similarity between the disked and chiseled treatments and the
remaining contributing factor is the influence of the heavier disk
used at the acid shale site which "cut in" more and thus left a surface
similar to chisel plowing. The influence that the earlier emergence
may have had with respect to giving a better appearance at the acid
shale site did not persist in the spring as plant densities and
heights were the same at both locations. This appearance of uniform
density was from a distance and upon closer insepction, the chiseled
and disked treatments had a higher plant population than the smooth
graded plots.
The degree to which legumes were established at the acid shale
site was much less than obtained on the other location. This most
likely was the result of a lower phosphorus status. Only two species
were established on all three tillage treatments and even then, stands
were poor.
44
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Alfalfa and sweet clover stands were ranked poor with birdsfoot
trefoil and red clover very poor. .y-.The_latter two. species were*found
only on the disked and chiseled treatments. On an occasional plot
could one find white clover plants while sericea lespedeza and
crownvetch plants were not observed on any tillage treatment with
one exception. In one area, fescue was not seeded and the various
legumes were seeded in pure stands. The reduced competition for
moisture on this adjacent area resulted in the establishment of
all seven legume species, however, stands were still poor for most, es-
pecially alfalfa, and red clover. On the other hand, sericea
lespedeza and birdsfoot trefoil were established as well as a few
scattered crownvetch plants.
Changes in chemical properties of the spoils. The data for the
pH values measured in water, KC1 and SMP buffer solutions are given
in Table 11. These data were averaged across all tillage and legume
treatments since there were no significant differences as the result
of these variables. The pH values measured in ^0 were indicative
of the acid nature of these spoils. Initially the pH was slightly
below the minimum standards for reclamation, but with time, the pH
decreased significantly as sulfide minerals underwent oxidation. The
largest amount of lime needed at any date being 9 metric tons/ha
which was' associated with the SMP buffer reading of 6.4.
Changes in available phosphorus with time are given in Table 12.
Data shown here in comparison with that from the slightly acid shale
site given in Table 8 are considerably different. Even though 84
kg/ha of phosphorus was applied, only a very small change was observed
in the subsequent samplings. Unfortunately, spoil samples were not
45
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Table 11. Changes In pH values following establishment of tillage-
legume treatments in September at the Acid Shale Site.
Time after
establishment pH measured in
in months H20 KC1 SMP buffer
0
5
8
13
5.0
5.5
4.4
3.7
4.6
5.2
4.0
3.4
7.2
6.7
6.8
6.4
46
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Table 12. Changes in Bray-1 phosphorus levels following the
establishment of tillage-legume treatments in September
"-. ' , , ,,.'.-)Ŧ'. :
at the acid shale location.
Time after
establishment
in months Chiseled
0* * 5
5 6
8 7
13 4
Tillage Treatment
Disked
Kg/ na
6
11
6
5
Smooth Graded
5
7
7
4
* Sampled prior to applying 84 kg/ha of phosphorus.
47
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collected one month after establishment at this site hence the rate
of fixation of the applied phosphorus cannot be characterized. The
-jĢ'Z -l /-,' ' '.:ŧ<&& ,r> >.!. " : f-ją... Bw'. tJf-
large amounts of iron released in conjunction of sulfide weathering
undoubtedly reacted with the phosphorus resulting in an insoluble
iron phosphate compound. Verification of this product with phosphorus
fractionation was not done.
The samples were not analyzed by exchangeable cations. The
levels of potassium, based on analyses from other areas and a few
samples tested by the soil testing laboratory, should have been
adequate throughout the duration of this study. The level of Ca,
and Mg may have been low relative to those reported earlier for the
neutral shale site, but on the other hand should have been high
enough so that these elements would not have restricted plant growth.
It is believed that the levels of Mn and Fe would have been high at
this site and this may have caused an imbalance for the other plant
nutrients. Such high levels, if they did in fact occur, would have
reduced the utilization of phosphorus in the plant tissue.
48
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Forage response to tillage treatments. As the result of poor
legume stands, only the alfalfa and sweet clover legume-tillage
combinations were harvested in May. The yield data from these harvests
are given in Table 13. In August, it was decided that we would harvest
all legume-tillage combinations, data presented in Table 14, hence
the yields for the alfalfa and sweet clover plots were cut the second
time. Combining the yield values for the latter two mentioned species
would be more reflective of the true differences in vegetative yield,
however, this was not done since we do not know the effect cutting
would have on the stimulation of regrowth of both the legume and grass
components.
It is apparent that even the total yields from either alfalfa or
sweet clover legume treatment were at least two orders of magnitude
less for the acid shale site than for the other location. The reason
for the reduction in yields from the more acid area is at least two
fold. First, the phosphorus levels were much lower and hence the
legume contribution to yield was greatly affected. These lower yields
may be also caused by the more acid conditions, however, more likely
these two factors are both contributing to yield depression and the
relationship may be a multiplying effect rather than a simple addition.
There was a significant difference between the average yields
obtained from the chiseled and smooth graded plots for the May harvest.
For the August harvest, significant differences in yields were obtained
between all three tillage treatments. Considering the effect of
tillage for any specific legume-fescue treatment, none of the tillage
treatments resulted in significant differences for either harvest
although a few approached the 5% significance level.
49
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Table 13. Effect of the tillage treatments on fescue-legume
jia a forage yields* for the May harvest at the acid shale site.
Legume - Ky 31 Tillage Treatment
Fescue Mixture Chiseled Disked Smooth Graded
Alfalfa
Sweet Clover
Mean
1555
846
1201
V /Vi
1074
737
905
585
501
543
*Yields adjusted to 10 percent moisture.
LSD ,- for tillage treatment means in 485 kg/ha
50
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Table 14. Effect of the tillage treatments on fescue-legume forage
yields* for the August harvest at the acid shale site.
Legume - Ky 31
Fescue Mixture
Alfalfa
Birdsfoot trefoil
Red Clover
White Clover
Sweet Clover
Crownvetch
Sericea Lespedeza
Mean - all legumes
Tillage Treatment
Chiseled
429
528
615
481
294
573
666
512
Disked
Kg/ na
231
453
432
437
169
372
587
383
Smooth Graded
143
340
332
333
210
484
338
262
* Yields adjusted to 10 percent moisture.
LSD ^c for tillage treatment means is 117 kg/ha.
si
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VERY ACID SANDSTONE SITE
Establishment of vegetative cover. A poor stand of both fescue
and the legume mixture was obtained on all plots regardless of lime
application rate if the lime had been incorporated. Those plots on
which lime was not incorporated were essentially void of plants. The
legume portion of the stand was dominated with alfalfa seedlings with
a few isolated plants of sweet clover,red clover, and birdsfoot trefoil,
Sericea lespedeza and crownvetch plants were not observed on any of
the lime treatments.
Changes in chemical properties of the spoils. The effect of lime
and the method of incorporation on pH levels as a function of sampling
depth as well as the vegetative yield are given in Table 15. These
data are means derived from four replications. Several trends are
noted; the most striking is that lime doesn't move appreciably below
the zone of incorporation even on sandy spoils. The pH of even the
5-10 cm depth was not as high as expected as both the disk and chisel
plow was operated to this depth. The 10-15 cm increment represents
spoil materials below the zone of incorporation. Upward movement of
water from the acid underlying zone into the 5-10 cm depth increment
may account for the low pH values obtained. It is also quite apparent
that incorporation is absolutely necessary and even the upper 5 cm of
the non-incorporated lime plots are acid.
The yields obtained from all plots are very low. There were
no significant differences between lime rates or methods of incorpora-
tion with the exception of the no-till treatment. The acid nature of
these spoils is of course the major contributor to the poor vegetative
growth but this is probably not the major cause of the low yields,
52
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Table 15. Effect of lime rate and method of incorporation on pH
levels sampled at three depth ^increments and forage yields.
Lime Rate and
Incorporation
Method
mt/ha
67.2
134.4
67.2
134.4
67.2
134.4
67.2
134.4
67.2
134.4
Disked
Disked
Chiseled
Chiseled
Disked*
Disked*
Chiseled**
Chiseled**
No-tillage
No-tillage
Sample Depth in
0-5
6.8
6.7
5.7
6.7
6.1
6.8
6.6
6.9
5.4
5.1
5-10
5.1
5.2
5.0
4.7
4.5
4.9
5.2
5.0
3.8
3.5
Centimeters Yield***
10-15
3.4
3.6
4.0
3.6
3.2
3.2
3.5
3.2
3.0
3.2
kg /ha
162
139
189
187
200
132
196
231
0
0
* Legume seeded in March whereas all other plots, legumes were
seeded in September.
** One-half lime applied, chiseled, followed by remaining lime
applied to the surface.
*** Yields adjusted to 10 percent moisture.
53
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at least not directly. The lack of moisture may be much more
important'.3 The acid''-zone prevents deep rooting and as the result of
the sandy nature of the spoils, the water holding capacity is very
low and plants should be under a moisture stress almost constantly.
Other plant species will be required on this spoil type if successful
reclamation is to be expected. Bermudagrass, Cynodon dactylon L.
Pers.j which is tolerant to both high temperatures and associated
droughty conditions may be a suitable substitute for Ky-31 tall
fescue.
54
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VI. REFERENCES
Barnhisel, R. I. and H. F. Massey. 1969. Chemical, mineralogical
and physical properties of eastern Kentucky acid-forming
coal spoil materials. Soil Sci. 108:367-372.
Berg, W. A. and W. G. Vogel. 1968. Manganese toxicity of legumes
seeded in Kentucky strip-mine spoils. U.S. Forest Service
Research Paper 119.
Berg, W. A. and R. F- May. 1969. Acidity and plant-available
phosphorus in strata overlying coal seams. Mining Congress
Journal. 55:31-34.
Berg, W. A. and W. G. Vogel. 1973. Toxicity of acid coal-mine spoils
to plants In Ecology and Reclamation of Devastated Lands.
Gordon and Breach, N.Y. Vol. 1. pp. 57-68.
Bray, R. H. and L. T. Kurtz. 1945. Determination of total, organic
and available forms of phosphorus in soils. Soil Sci.
59:39-45.
Chang, S. C. and M. L. Jackson. 1957. Fractionation of soil
phosphorus. Soil Sci. 84:133-144.
Cummins, D. G., W. T. Plass and C. E. Gentry. 1967. Chemical and
physical properties of spoil banks in eastern Kentucky coal
fields. U.S. Forest Service Res. Paper CS-17. Central States
For. Exp. Sta. Columbus, 0. 12 pp.
Curtis, W. 1971. Strip mining and sedimentation. Transactions of
the Amer. Soc. Agr. Engin. 14:434-436.
Curtis, W- R- and W. 0. Cole. 1972. Micro-topographic profile
gauge. Agric. Eng. 53(1):17.
55
-------
Czapowskyj , M. M. 1976. Annotated bibliography on the ecology
and reclamation1 (of drastically disturbed areas. USDA 'For. Serv.
Gen. Tech. Rep. NE-21.
Funk, D. T. 1962. A revised bibliography of strip-mine reclamation.
USDA Forest Serv- Central States For. Exp. Sta. Misc. Pub. 35.
Massey, H. F. 1972. pH and soluble Cu, Ni and Zn in eastern
Kentucky coal mine spoil materials. Soil Sci. 114:217-221.
Massey, H. F. and R. I. Barnhisel. 1972. Copper, nickel and zinc
released from acid coal mine spoil materials of eastern
Kentucky. Soil Sci. 113:207-212.
Plass, W. T. 1969. Pine seedlings respond to liming of acid
strip-mine spoils. USDA Forest Serv. Res. Note NE - 103.
Plass, W. T. and W. G. Vogel. 1973. Chemical properties and particle-
size distribution of 39 surface-mined spoils in southern
West Virginia. USDA Forest Serv. Res. Paper NE-276, 8 pp.
Shoemaker, H. E., E. 0. McLean and P. F. Pratt. 1961. Buffer methods
for determining lime requirement of soils with appreciable
amounts of extractable aluminum. Soil Sci. Soc. Amer. Proc.
25:274-277.
Sutton, P. 1973. Reclamation of toxic strip-mine spoil banks.
Ohio Report. 58:18-20.
Vimmerstedt, J. P. 1970. Strip-mine reclamation. Ohio Report.
55:60-61. ' '
Vogel, W. G. 1973. The effect of herbaceous vegetation on survival
and'growth of trees planted on coal-mine spoils. Research and
Applied Tech. Symp. on Mined-Land Reclamation, pp. 197-207.
56
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TECHNICAL REPORT DATA
(f lease read Instructions on the reverse before completing)
REPORT NO.
EPA-600/7-77-093
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
Reclamation of Surface Mined Coal Spoils
5. REPORT DATE -
August 1977
issuing date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Richard I. Barnhisel
8. PERFORMING ORGANIZATION REPORT NO
CSRS 1
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Kentucky Agricultural Experiment Station
Agronomy Department
University of Kentucky
Lexington, Kentucky 40506
10. PROGRAM ELEMENT NO.
526
11. CONTRACT/GRANT NO.
CSRS 684-15-3
EPA-IAG D6-E762
12. SPONSORING AGENCY NAME AND ADDRESS
Industrial Environmental Research Laboratory - Cin., OH
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
Final Report
14. SPONSORING AGENCY CODE
600/12
15. SUPPLEMENTARY NOTES
Project was in cooperation with the TI.S.D.A. Cooperative States Research Service (CSRS
16. ABSTRACT
A project was conducted to demonstrate the effect of tillage including:
subsoiling or ripping, disking, chisel plowing as a means of creating a rough micro-
relief as compared to smooth graded surface mined coal spoils. It was found that when
the surface was rough, increased plant growth occurred at all levels of applied
phosphorus. Yields were also improved with the use of a mulch and when used in
combination with phosphorus and subsoiling, approach those yields of nonmined land.
Lime additions should be made according to soil tests in which both active as
well as total potential acidity as the result of oxidation of sulfide minerals are
determined. When required, lime should be incorporated into the spoils by disking,
etc.; this practice increas.es the rooting depth and thus reduces the droughty nature
of acid spoils.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Ecology, Environments, Earth Atmosphere,
Environmental Engineering, Geography,
Hydrology, Limnology, Biochemistry, Earth
Hydrosphere, Combustion, Refining, Energy
Conversion Heat Sources, Materials
Handling, Inorganic Chemistry, Organic
Chemistry, Chemical Engineering
b.lDENTIFIERS/OPEN ENDED TERMS
Coal
COSATI Field/Group
6F
8H
7B
8A 8F
10A 10B
7C 13B
S. DISTRIBUTION STATEMENT
Release to the Public
19'
21. NO. OF, PAGES
67
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
57
&U.S. GOVERNMENT PRINTING OFFICE: 1977- 757-056/6553
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