The Water Quality Information Center at the National Agricultural Library
Agricultural Research Service, U. S. Department of Agriculture
Environmental Effects of U.S. Department
of Agriculture Conservation Programs
A Conservation Effects
Assessment Bibliography
Special Reference Briefs
Series no. SRB 2004-01
Compiled by
Stuart R. Gagnon
Joseph R. Makuch
Ted J. Sherman
Water Quality Information
Center
National Agricultural
Library
Agricultural Research
Service
U.S. Department of
Agriculture
454 citations
National Agricultural Library Beltsville, Maryland 20705-2351 August 2004
National
Agricultural Library Cataloging Record:
Gagnon, Stuart
R.
Environmental
effects of U.S. Department of Agriculture conservation programs : a
conservation effects assessment bibliography.
(Special reference
briefs ; NAL-SRB. 2004-01)
1. Water in
agriculture--United States--Bibliography.
2.Water
quality--United States--Bibliography.
3. Agricultural
pollution--United States--Bibliography.
4.Agriculture and
state--Environmental aspects--United
States--Bibliography.
I. Makuch, Joseph
R. II. Sherman, Ted J. III. Water Quality Information Center
(U.S.)
III. Title.
aZ5071.N3 no.
2004-01
Abstract
Environmental Effects of U.S.
Department of Agriculture Conservation Programs , Special Reference Brief 2004-01. U.S.
Department of Agriculture, National Agricultural
Library.
This bibliography is one in a
multi-volume set developed by the Water Quality Information Center
at the National Agricultural Library in support of the U.S.
Department of Agriculture's (USDA) Conservation Effects Assessment
Project (CEAP). The bibliography is a guide to literature examining
environmental effects of USDA conservation programs. The
information is useful for assessing on-the-ground results of conservation programs
from various environmental perspectives.
Keywords: conservation
programs, environmental quality, program
evaluation, agricultural research, Conservation Reserve
Program ,
Wildlife Habitat Incentives Program, Farm Bill
Mention of trade names or
commercial products in this report is solely for the purpose of
providing specific information and does not imply recommendation or
endorsement by the U.S. Department of Agriculture.
To ensure timely distribution,
this report has been reproduced essentially as supplied by the
authors. It has received minimal publication editing and
design. The authors' views are their own and do not
necessarily reflect those of the U.S. Department of
Agriculture.
The
U.S. Department of Agriculture prohibits discrimination in all its
programs and activities on the basis of race, color, national
origin, sex, religion, age, disability, political beliefs, sexual
orientation, or marital or family status. (Not all prohibited bases
apply to all programs.) Persons with disabilities who require
alternative means for communication of program information
(Braille, large print, audiotape, etc.) should contact USDA's TARGET
Center at (202) 720-2600 (voice and TDD).
To file a complaint of
discrimination, write USDA, Office of Civil Rights, Room 326-W,
Whitten Building, 1400 Independence Avenue, SW, Washington D.C.
20250-9410 or call (202) 720-5964 (voice and TDD). USDA is an equal
opportunity provider and employer.
August 2004
| Preface | 1 |
| About This Bibliography | 2 |
| Climate Change and Air Quality | 3 |
| Soil | 9 |
| Water | 21 |
| Wildlife Habitat | 35 |
| Other Environmental Effects | 75 |
| Multiple Environmental Effects | 97 |
| Subject Index | 113 |
| Author Index | 131 |
This is one in a series of bibliographies
developed by the Water Quality Information Center at the National
Agricultural Library in support of the U.S. Department of
Agriculture's Conservation Effects Assessment Project (CEAP).
The purpose of CEAP is to study
the environmental effects of conservation practices implemented
through various U.S. Department of Agriculture conservation
programs. CEAP will evaluate conservation practices and management
systems related to nutrient, manure, and pest management; buffer
systems; tillage; irrigation and drainage practices; wetland
protection and restoration; and wildlife habitat establishment.
More information about CEAP is available at www.nrcs.usda.gov/technical/nri/ceap/.
The current titles in this series are
Each of the documents, as well as bibliographies on similar topics, is accessible online from the Water Quality Information Center at www.nal.usda.gov/wqic/.
The center gratefully acknowledges the following organizations who granted permission to use their citations and/or abstracts in these bibliographies.
In
addition, support from the Natural Resources Conservation Service
for the development of these bibliographies is greatly appreciated.
Joseph R. Makuch, Ph.D.
Coordinator
Water Quality Information
Center
About This Bibliography
This bibliography is a guide to
literature examining environmental effects of U.S. Department of
Agriculture (USDA) conservation programs. Examples of programs
covered are the Conservation Reserve Program, Environmental Quality
Incentives Program, Wetlands Reserve Program, and Wildlife Habitat
Incentives Program. The purpose of this bibliography is to provide
an overview of various environmental outcomes resulting from
landowner participation in USDA conservation programs. This
information is useful for assessing on-the-ground results of
conservation programs from various environmental
perspectives.
There are 454 citations with
abstracts (when available) in this bibliography. Citations were
found through literature searches of the AGRICOLA database,
produced by the National Agricultural Library, and several
commercial bibliographic databases. Many relevant citations were
also found in Final
Programmatic Environmental Impact Statement for the Conservation
Reserve Program (CRP) ,
citation number 416. In addition, Water Quality Information
Center staff created citations for documents that were located by
various other means. Documents cited were published from 1985
through 2003 (with a few included from early 2004). URLs are
provided for online documents that are freely available. The
inclusion or omission of a particular citation does not imply
endorsement or disapproval.
Citations are grouped in these
categories: Climate Change and Air Quality, Soil, Water, Wildlife
Habitat, Other Environmental Effects, and Multiple Environmental
Effects. Within these sections, citations are arranged
alphabetically by title.
To locate information on a
specific topic, for example, conservation tillage, use the subject
index beginning on page 113. To ensure that you see all the
relevant citations for a particular topic, be sure to also look up
related terms in the subject index, for example, no till, ridge
till, etc., from the example above. An author index is also
available beginning on page 131.
To obtain a specific document,
please contact your local library. Information on how to obtain
documents from the National Agricultural Library can be found
at www.nal.usda.gov/ddsb/.
Climate Change and Air Quality
1. Assessment of Alternative Management
Practices and Policies Affecting Soil Carbon in Agroecosystems of
the Central United States.
Donigian, A. S.; Barnwell, T. O.;
Jackson, R. B.; Patwardhan, A. S.; and Weinrich, K. B.
Washington, DC: U.S. Environmental
Protection Agency; EPA600R94067, 1994.
Notes: Contract: EPA68CO0019; Prepared in cooperation
with Computer Sciences Corp., Athens, GA. and Colorado State Univ.,
Fort Collins. Natural Resource Ecology Lab. Sponsored by
Environmental Research Lab., Athens, GA.
http://www.epa.gov/cgi-bin/claritgw?op-Display&document=clserv:ORD:0762;&rank=4&template=epa
Descriptors:
Emissions/ Ecosystems/ Mathematical
models/ Economic model/ Conservation/ Reduction/ Carbon dioxide/
Land use/ Farm crops/ Cultivation/ Yield/ Regions/ United States/
Trends/ Tables Data/ Climatic changes/ Soil properties/ Carbon/
Organic matter/ Farm management/ Air pollution and control/
Environmental pollution and control/ Agriculture and food/
Agricultural economics/ Agricultural equipment facilities and
operations/ Natural resources and earth sciences/ Soil sciences/
Medicine and biology/ Ecology/ Atmospheric
sciences/ Physical meteorology
Abstract: The goal of the U.S. EPA BIOME
Agroecosystems Assessment Project is to evaluate the degree to
which agroecosystems can be technically managed, on a sustainable
basis, to conserve and sequester carbon, reduce the accumulation of
carbon dioxide in the atmosphere, and provide reference datasets
and methodologies for agricultural assessment. The report provides
preliminary estimates of carbon sequestration potential for the
central United States including the Corn Belt, the Great Lakes, and
portions of the Great Plains. This study region comprises 44% of
the land area and 60% to 70% of the agricultural cropland of the
conterminous United States. The assessment methodology includes the
integration of the RAMS economic model, the Century soil carbon
model, meteorologic and soils data bases, and GIS display and
analysis capabilities in order to assess the impacts on soil carbon
of current agricultural trends and conditions, alternative tillage
practices, use of cover crops, and Conservation Reserve Program
policy.
2. Assessment of alternative soil management
practices on N2O emissions from US agriculture.
Mummey, D. L.; Smith, J. L.; and
Bluhm, G.
Agriculture, Ecosystems and
Environment 70
(1): 79-87. (1998)
NAL Call #:
S601 .A34; ISSN: 0167-8809
This citation is provided courtesy
of CAB International/CABI Publishing.
3. Carbon and Nitrogen Sequestration in Two
Prairie Topochronosequences on Contrasting Soils in Southern
Wisconsin.
Brye, KR and Kucharik,
CJ
American Midland
Naturalist 149 (1):
90-103. (Jan. 2003)
NAL Call #:
410 M58; ISSN: 0003-0031
Descriptors:
Conservation Reserve Program/
Organic Matter Recovery/ Grassland Soils/ Cultivation/
Accumulation/ Abandonment/ Dynamics/ Storage/ Sink
Abstract: Prairie restoration has the potential to
sequester nitrogen (N) and atmospheric carbon (C) in the soil, but
the capability of a site to respond positively to prairie
restoration depends on numerous factors such as soil parent
material, topography and time. Soil bulk density in the top 10 cm
and C and N concentrations at several intervals to a depth of 1 m
were measured in a tallgrass prairie topochronosequence at fine-
and coarse-textured soil locations to evaluate the role of texture,
slope and ecosystem age in controlling C and N sequestration
following cessation of cultivation and subsequent prairie
restoration. Soil C and N concentrations, contents and C:N ratios
were significantly greater in fine-textured soils compared to sites
with coarse-textured soil. Soil texture generally did not explain
variations in the amounts or rates of C and N sequestration in the
restored prairies. Soil surface bulk density was significantly
correlated with slope, but not ecosystem age, at sites with
coarse-textured soil. Within the limits of this study, neither
slope nor ecosystem age were correlated to bulk density at sites
with fine-textured soil. Soil C content in the top 25 cm increased
significantly as ecosystem age increased for the restored and
remnant prairies at the fine-textured location, but not at the
coarse-textured location. Results demonstrate that a combination of
soil parent material, topography and time since cessation of
cultivation control the content and accumulation of C and N
following prairie restoration. In the context of this study, the
bottom line is that significant C sequestration was not achieved,
given the current level and types of restoration management, within
two and a half decades following conversion of cultivated cropland
to prairie.
© Thomson ISI
4. Carbon dynamics of the Conservation and
Wetland Reserve Programs.
Barker, J. R.; Baumgardner, G. A.;
Turner, D. P.; and Lee, J. J.
Journal of Soil and Water
Conservation 51
(4): 340-346. (July 1996-Aug.
1996)
NAL Call #:
56.8-J822; ISSN: 0022-4561 [JSWCA3]
Descriptors:
land use/ conversion/ carbon cycle/
woodlands/ grasslands/ farmland/ afforestation/ carbon/ atmosphere/
air pollution/ greenhouse effect/ land management/ federal
programs/ forest soils/ grassland soils/ agricultural soils/
trends/ Conservation Reserve Program/ carbon sequestration/
nutrient dynamics/ carbon pools/ global carbon budget/ greenhouse
gases/
croplands/ forestlands
This citation is from
AGRICOLA.
5. Climate and weather of the Great
Plains.
Wilken, G. C.
In: General Technical Report RM;
Vol. 158.
Fort Collins, Colo.: Rocky
Mountain Forest and Range Experiment Station, 1988; pp.
18-20.
Notes: Report Series ISSN: 0277-5786; Proceedings of a
Symposium on "Impacts of the Conservation Reserve Program in the
Great Plains," held Sept 16-18, 1987, Denver, Colorado. Includes
references.
NAL Call #: aSD11.A42
Descriptors:
weather/ climate/ northern plains
states of USA/ southern plains states of USA
This citation is from
AGRICOLA.
6. Conservation practices in U.S. agriculture
and their impact on carbon sequestration.
Uri, Noel D.
Environmental Monitoring
and Assessment 70 (3):
323-344. (2001)
NAL Call #:
TD194.E5; ISSN: 0167-6369
Descriptors:
carbon: soil sequestration
practices/ Conservation Reserve Program/ United States agriculture:
conservation practices/ comprehensive effort/ conservation buffer
strips/ conservation practices: evolution/ soil
conservation:
individual, site
specific
Abstract: Increase in the use of conservation
practices by agriculture in the United States will enhance soil
organic carbon and potentially increase carbon sequestration. This,
in turn, will decrease the net emission of carbon dioxide. A number
of studies exist that calibrate the contribution of various
individual, site-specific conservation practices on changes in soil
organic carbon. There is a general absence, however, of a
comprehensive effort to measure objectively the contribution of
these practices including conservation tillage, the Conservation
Reserve Program, and conservation buffer strips to an change in
soil organic carbon. This paper fills that void. After recounting
the evolution of the use of the various conservation practices, it
is estimated that organic carbon in the soil in 1998 in the United
States attributable to these practices was about 12.2 million
metric tons. By 2008, there will be an increase of about 25%. Given
that there is a significant potential for conservation practices to
lead to an increase in carbon sequestration, there are a number of
policy options that can be pursued.
© Thomson
7. Conservation Reserve Program: Effects on
soil organic carbon and preservation when converting back to
cropland in northeastern Colorado.
Bowman, R. A. and Anderson, R.
L.
Journal of Soil and Water
Conservation 57
(2): 121-126. (2002)
NAL Call #:
56.8 J822; ISSN: 0022-4561
Descriptors:
United States, Colorado/ Watershed
Management/ Agricultural Practices/ Organic Carbon/ Soil Chemistry/
Soil Conservation/ Tillage/ Crops/ Watershed protection
Abstract: Information on the potential for carbon
sequestration from the Conservation Reserve Program (CRP) and
knowledge concerning the fate of accrued carbon on sod takeout and
recropping to a wheat-based rotation are essential. We conducted
two separate field studies in northeastern Colorado to quantify the
soil organic carbon (SOC) changes after various amounts of time in
the CRP program, and to assess problems associated with converting
CRP grass to cropland and the potential for loss of accrued SOC
with different tillage systems. For our first objective, we
assessed six CRP sites, with three sites showing increased SOC
content over the adjacent winter wheat/summer fallow sites, and
three sites showing no differences. In the conversion study,
systems with little or no tillage yielded more winter wheat
(Triticum aestivum L.) grain than systems with tillage because of
more available soil water at planting time. Furthermore, SOC loss
was less with no-till and reduced-till (herbicides plus one
tillage) systems than by conventional tillage with numerous sweep
plow operations. Thus, NT and reduced-till systems designed to
control perennial CRP grasses will enable producers to maintain
some of the gains in SOC when CRP land is converted to
cropland.
© Cambridge Scientific Abstracts
(CSA)
8. Considering offsite wind erosion benefits
in the decision to implement soil conservation practices: An
example using the Conservation Reserve Program.
Piper, S.
Applied Agricultural
Research 5 (3): 153-158.
maps. (Summer 1990)
NAL Call #:
S539.5.A77; ISSN: 0179-0374 [AAREEZ]
Descriptors:
wind erosion/ decision making/ soil
conservation/ cost benefit analysis/ public expenditure/ social
benefits/ program effectiveness/ United States/ offsite benefits/
onsite benefits
Abstract: Wind erosion in the western United States
results in substantial offsite and onsite damages. These damages
can be reduced by implementing soil conservation measures to
decrease the level of wind erosion on agricultural land. Soil
conservation decisions by farmers are based primarily on the amount
of onsite benefits possible from erosion control. However, both
onsite and offsite benefits must be considered in order to attain a
socially desirable level of soil conservation. Estimates of the
offsite and onsite benefits from the Conservation Reserve Program
indicate that excluding offsite benefits from the soil conservation
decision results in a substantially lower than socially desirable
level of soil conservation.
This citation is from
AGRICOLA.
9. CRP and microbial biomass dynamics in
temperate climates.
Follett, R. F.
In: Management of carbon
sequestration in soil/
Lal, R.; Kimble, J. M.; Follet, R.
F.; and Stewart, B. A.; Series: Advances in soil
science.
Boca Ration, Fla.: CRC Press,
1998; pp. 305-322.
Notes: ISBN: 0849374421; Paper presented at the
symposium "Carbon sequestration in soils,"
held July, 1996, The Ohio State
University
NAL Call #: S592.6.C35M35-1998
Descriptors:
soil flora/ biomass/ soil/ quality/
land use/ soil management/ federal programs/ soil conservation/
Conservation Reserve Program
This citation is from
AGRICOLA.
10. The CRP increases soil organic
carbon.
Gebhart, D. L.; Johnson, H. B.;
Mayeux, H. S.; and Polley, H. W.
Journal of Soil and Water
Conservation 49
(5): 488-492. (1994)
NAL Call #:
56.8 J822; ISSN: 0022-4561
Descriptors:
soil conservation/ soil organic
matter/ carbon/ cropland/ pastures/ land use/ cultivated lands/
organic carbon/ crops/ Watershed protection/ Land pollution/
Conservation
Abstract: The land use change from cropland to
perennial grass cover associated with the Conservation Reserve
Program (CRP) may sequester atmospheric CO sub(2) back into the
soil carbon pool, thereby changing formerly cultivated soils from
sources to sinks for atmospheric carbon. To evaluate the effect of
CRP on soil organic carbon (SOC) levels, samples from adjacent
cropland, native pasture, and five year old CRP sites in Texas,
Kansas, and Nebraska were analyzed. Across all locations, SOC
levels for cropland, CRP, and native pasture were 59.2, 65.1, and
90.8 metric tons C/ha in the surface 300 cm, respectively. CRP
lands gained an average of 1.1 tons C/ha/yr suggesting that the 17
million hectares of land enrolled in CRP may have the potential to
sequester about 45% of the 38.1 million tons of carbon released
annually into the atmosphere from U.S. agriculture. These findings
illustrate that agricultural CO sub(2) emissions may be effectively
controlled through changes in land use and management
systems.
© Cambridge Scientific Abstracts
(CSA)
11. Evaluating the environmental effects of
agricultural policy: The soil bank, the CRP, and airborne
particulate concentrations.
Ringquist, R. J.; Lee, J.; and
Ervin, R. T.
Policy Studies
Journal 23: 519-533. (Fall
1995); ISSN:
0190-292X
Descriptors:
United States---Environmental
policy/ Air pollution---United States/ Agriculture---United
States---Legislation/ Soil conservation---United States
Legislation/ United States---Agricultural policy---Legislation/
Soil erosion---Environmental aspects/ Agriculture---Environmental
aspects
Abstract: Finds significant improvement in air
quality as a result of soil conservation provisions of the 1985 and
1990 Farm bills; some focus on the 1985 Conservation Reserve
program; US. Analysis of reduction in air-borne dust in the
Southern High Plains region.
© 2004 PAIS, published by OCLC
Public Affairs Information Service
12. Forest carbon sinks: Costs and effects of
expanding the Conservation Reserve Program.
Parks, P. J. and Hardie, I.
W.
Choices 11 (2): 37-39. (1996)
NAL Call #:
HD1751.C45; ISSN: 0886-5558
Descriptors:
forests/ carbon/ federal programs/
program participants/ farmland/ land diversion/
United States/ carbon
emission
This citation is from
AGRICOLA.
13. Land management effects on nitrogen and
carbon cycling in an Ultisol.
Torbert, H. A.; Prior, S. A.; and
Reeves, D. W.
Communications in Soil
Science and Plant Analysis 30 (9/10): 1345-1359. (1999)
NAL Call #:
S590.C63; ISSN: 0010-3624 [CSOSA2]
Descriptors:
ultisols / nitrogen cycle/ carbon
cycle/ land management/ soil fertility/ tillage/ conservation
tillage/ cover crops/ fallow systems/ cropping systems/ gossypium
hirsutum/ triticum aestivum/ pinus taeda/ Alabama
Abstract: Soil carbon (C) content in agro-systems
is important in a global context because of the potential for soil
to act as a sink for atmospheric CO(2). However, soil C storage in
agro-ecosystems can be sensitive to land management practices. The
objective of this study was to examine the impact of land
management systems on C and nitrogen (N) cycling in an Ultisol in
Alabama. Soil samples (0-10,10-20, and 20-30 cm depths) were
collected from a Marvyn sandy loam soil (fine-loamy, siliceous,
thermic Typic Hapludults) under five different farm scale
management systems for at least 5 years. The five systems were
cotton (Gossypium hirsutum L.) production managed with 1)
conventional tillage only, 2) conventional tillage with a grazed
winter cover crop (wheat, Triticum aestivum L.), 3) conservation
tillage with a winter cover crop grown for cover only with strip
tillage; or taken out of cotton production with either 4)
long-term-fallow (mowed), or 5) Conservation Reserve Program with
loblolly pine (Pinus taeda L.) (CRP-pine). Total N, total organic C
(TOC), total P, and soil C:N ratios were determined. Potential C
mineralization, N mineralization, C turnover and C:N mineralization
ratios were determined on samples during a 30-day laboratory
incubation study. The fallow system had significantly higher TOC
concentration (7.7 g kg(-1) C) while the CRP-pine system had lower
TOC concentration (3.1 g kg(-1) C) compared with the farmed
management systems (approximately equal to 4.7 g kg(-1) C). The
fallow system had a significantly lower C turnover at all three
soil depths compared with the other management systems. At the 0-10
cm depth, the highest C:N mineralization ratio levels were observed
in management systems receiving the most tillage. Our results
indicate that for Ultisols in the Southeast the use of surface
tillage in land management systems is a controlling factor which
may limit soil C sequestration.
This citation is from
AGRICOLA.
14. National-Scale Estimation of Changes in
Soil Carbon Stocks on Agricultural Lands.
Eve, MD; Sperow, M; Paustian, K;
and Follett, RF
Environmental
Pollution 116 (3): 431-438.
(2002)
NAL Call #:
QH545.A1E52; ISSN: 0269-7491
Descriptors:
Carbon Sequestration/ Global
Change/ Land Use Change/ IPCC Inventory/ Carbon Dioxide (CO2) /
Greenhouse Gas/ Conservation Tillage/ Organic Carbon/
Sequestration/ Resources/ Dynamics/ Matter/ Sinks
Abstract: Average annual net change in soil carbon
stocks under past and current management is needed as part of
national reporting of greenhouse gas emissions and to evaluate the
potential for soils as sinks to mitigate increasing atmospheric
CO2. We estimated net soil C stock changes for US agricultural
soils during the period from 1982 to 1997 using the IPCC
(Intergovernmental Panel on Climate Change) method for greenhouse
gas inventories. Land use data from the NRI (National Resources
Inventory; USDA-NRCS) were used as input along with ancillary data
sets on climate, soils, and agricultural management. Our results
show that, overall, changes in land use and agricultural management
have resulted in a net gain of 21.2 MMT C year(-1) in US
agricultural soils during this period. Cropped lands account for
15.1 MMT C year(- 1), while grazing land soil C increased 6.1 MMT C
year(-1). The land use and management changes that have contributed
the most to increasing soil C during this period are (1) adoption
of conservation tillage practices on cropland, (2) enrollment of
cropland in the Conservation Reserve Program, and (3) cropping
intensification that has resulted in reduced use of bare fallow.
(C) 2001 Elsevier Science Ltd. All rights reserved.
© Thomson ISI
15. Potential carbon benefits of the
Conservation Reserve Program in the United States.
Barker, J. R.; Baumgardner, G. A.;
Turner, D. P.; and Lee, J. J.
Journal of
Biogeography 22 (4-5):
743-751. (1995)
NAL Call #:
QH1.J62; ISSN: 0305-0270.
Notes: Conference: 1. GCTE Science Conference, Woods
Hole, MA (USA), 23-27 May 1994
Descriptors:
USA/ carbon sinks/ land
improvement/ vegetation changes/ climatic changes/ Conservation
Reserve Program/ Conservation
Abstract: Three scenarios of the Conservation
Reserve Program (CRP) were simulated to project carbon (C) pools
and fluxes of associated grassland and forestland for the years
1986-2035; and to evaluate the potential to offset greenhouse gas
emissions through C sequestration. The approach was to link
land-area enrolments with grassland and forestland C densities to
simulate C pools and fluxes over 50 years. The CRP began in 1986
and by 1996 consisted of 16.2 x 10 super(6) ha cropland converted
to 14.7 x 10 super(6) ha grassland and of 1.5 x 10 super(6) ha
forestland. The CRP1 simulated the likely outcome of the CRP as
contracts expire in 1996 with the anticipated return of 8.7 x 10
super(6) ha grassland and of 0.4 x 10 super(6) ha forestland to
crop production. The CRP2 assumed that the CRP continues with no
land returning to crop production. The CRP3 was an expansion of the
CRP2 to include afforestation of 4 x 10 super(6) ha new land.
Average net annual C gains for the years 1996-2005 were < 1, 12,
and 16 TgC yr super(-1) for CRP1, CRP2, and CRP3, respectively.
Afforestation of marginal cropland as simulated under CRP3 could
provide approximately 15% of the C offset needed to attain the
Climate Change Action Plan of reducing greenhouse gas emissions to
their 1990 level by the year 2000 within the United
States.
© Cambridge Scientific Abstracts
(CSA)
16. Soil carbon sequestration and the
greenhouse effect: Proceedings of a symposium, 90th Annual
Meeting.
Lal, R.
Madison, WI: Soil Science Society
of America; xvii, 236. (2001)
Notes: Meeting held 18-22 October 1998 at Baltimore,
MD.; ISBN:
0-89118-836-3
This citation is provided courtesy
of CAB International/CABI Publishing.
17. Soil Change and Carbon Storage in Longleaf
Pine Stands Planted on Marginal Agricultural Lands.
Markewitz, D; Sartori, F; and
Craft, C
Ecological
Applications 12 (5):
1276-1285. (Oct. 2002)
NAL Call #:
QH540.E23; ISSN: 1051-0761
Descriptors:
Carbon Storage/ Conservation
Reserve Program/ Longleaf Pine/ Marginal Agricultural Lands/ Soil
Cations/ Soil Change/ Soil Nitrogen/ Soil Phosphorus/ Wiregrass
Savannas/ Ecosystem Function/ Loblolly Pine/ 3 Decades Forest/
Sequestration/ Patterns/ Turnover
Abstract: An increasing area of marginal
agricultural land in the coastal plain of the southeastern United
States is being planted to longleaf pine (Pinus palustris Mill.).
This chronosequence study in southern Georgia evaluated the effect
of pine planting and the associated cessation of agricultural
activity such as tillage and fertilization on soil C storage and
soil nutrient stocks. Soils are Arenic or Typic Kandiudults with
coarse- textured surface soils. Soil C, nutrients, and bulk density
from 0 to 50 cm in planted stands 1, 3, 7, and 14 yr old, as well
as soils beneath natural longleaf pine stands that were in a never
tilled (NT) condition, were evaluated (n = 3 per stand age). No
accumulation of soil C was apparent during the first 14 yr of pine
growth. The average content of soil C in planted stands (11 +/- 1
Mg/ha; mean +/- 1 SE) was similar to 16 Mg/ha less than that in the
NT soils (27 +/- 4 Mg/ha). Soil total N content within planted
stands also did not differ by age, although extractable NO,
declined rapidly. Despite agricultural N inputs, the mean N content
of planted stands (410 +/- 83 Mg/ha) was below that in NT stands
(730 +/- 21 Mg/ha). Total P (1507 +/- 21 Mg/ha) and extractable P
(113 -_ 21 Mg/ha) contents also did not differ between planted
stands but had highly elevated values compared to total P (728 -_
38 Mg/ha) and extractable P (2 +/- 1 Mg/ha) for NT soils. Soil
exchangeable Ca, Mg, and K had generally decreasing contents with
stand age but varying patterns related to NT soils. During the
first 14 yr of reforestation, soils did not sequester C. Carbon
benefits may be gained, however, in above-ground and belowground
biomass accumulation and through the cessation of high
energy-consumptive activities such as fertilization or tillage.
Enhanced P fertility on these marginal lands can improve pine
growth, but only if other elements such as N are not limiting to
growth.
© Thomson ISI
18. Soil management concepts and carbon
sequestration in cropland soils.
Follett, R. F.
Soil and Tillage
Research 61 (1/2): 77-92.
(2001)
NAL Call #:
S590.S48; ISSN: 0167-1987
This citation is provided courtesy
of CAB International/CABI Publishing.
19. Statistical Assessment of a Paired-Site
Approach for Verification of Carbon and Nitrogen Sequestration on
Wisconsin Conservation Reserve Program Land.
Kucharik, CJ; Roth, JA; and
Nabielski, RT
Journal of Soil and Water
Conservation 58 (1): 58-67.
(Jan. 2003-Feb. 2003)
NAL Call #:
56.8 J822; ISSN: 0022-4561
Descriptors:
Agricultural Land Management/
Carbon Sequestration / CRP/ Soil Organic Matter/ Wisconsin/ Organic
Matter Recovery/ Particle Size Analysis/ Soil Carbon/ Quality/
Switchgrass/ Management/ Grassland/ Storage/ Fields/
Bulk
Abstract: The threat of global climate change has
provoked policy-makers to consider plausible strategies to slow the
accumulation of greenhouse gases-especially carbon dioxide (CO2)-in
the atmosphere. One such idea involves the sequestration of
atmospheric carbon (C) in degraded agricultural soils as part of
the Conservation Reserve Program (CRP). While the potential for
significant C sequestration in CRP grassland ecosystems has been
demonstrated, the paired-site sampling approach traditionally used
to quantify soil C changes has not been evaluated with robust
statistical analysis. In this study, 14 paired CRP (> 8 years
old) and cropland sites in Dane County, Wisconsin, were used to
assess whether a paired-site sampling design could detect
statistically significant differences (ANOVA) in mean soil organic
C and total nitrogen (N) storage. We compared 0 to 10 cm (0 to 3.9
in) bulk density and sampled soils (0 to 5 cm, 5 to 10 cm, and 10
to 25 cm [0 to 2 in, 2 to 3.9 in, and 3.9 to 9.8 in]) for textural
differences and chemical analysis of organic matter (OM), soil
organic C (SOC), total N, and pH. The CRP contributed to reducing
soil bulk density by 13% (p < 0.001) and increased SOC and OM
storage (kg m(-2) [lb ft(-2)]) by 13% to 17% in the 0 to 5 cm (2
in) layer (p = 0.1). We tested the statistical power associated
with ANOVA for measured soil properties and calculated minimum
detectable differences (MDD). We concluded that 40 to 65 paired
sites and soil sampling in 5 cm (2 in) increments near the surface
were needed to achieve an 80% confidence level (a = 0.05;
β = 0.20) in soil C and N sequestration rates. Because
soil C and total N storage was highly variable among these sites
(CVs > 20%), only a 23% to 29% change in existing total organic
C and N pools could be reliably detected. While C and N
sequestration (247 kg C ha(-1) yr(-1) and 17 kg N ha(-1) yr(-1)
[220 lb C ac(-1) and 15 lb N ac(-1)]) may be occurring and confined
to the surface 5 cm (2 in) as part of the Wisconsin CRP, our
sampling design did not statistically support the desired 80%
confidence level. We conclude that usage of statistical power
analysis is essential to insure a high level of confidence in soil
C and N sequestration rates that are quantified using paired
plots.
© Thomson ISI
20. Uncertainty in estimating land use and
management impacts on soil organic carbon storage for US
agricultural lands between 1982 and 1997.
Ogle, S. M.; Breidt, F. J.; Eve,
M. D.; and Paustian, K.
Global Change
Biology 9 (11): 1521-1542.
(2003)
NAL Call #:
QC981.8.C5G6323; ISSN: 1354-1013.
Notes: Number of References: 143;
Publisher: Blackwell Publishing
Ltd
Descriptors:
Environment/ Ecology/
agroecosystems/ carbon sequestration/ greenhouse gas mitigation/
IPCC/ land use change/ uncertainty analysis/ Conservation Reserve
Program/ fine sandy loam/ cultivated grassland soils/ Carbon 13
natural abundance/ fallow tillage systems/ long term tillage/
southwestern Saskatchewan/ crop rotations/ great plains/ nitrogen
fertilization
Abstract: Uncertainty was quantified for an
inventory estimating change in soil organic carbon (SOC) storage
resulting from modifications in land use and management across US
agricultural lands between 1982 and 1997. This inventory was
conducted using a modified version of a carbon (C) accounting
method developed by the Intergovernmental Panel on Climate Change
(IPCC). Probability density functions (PDFs) were derived for each
input to the IPCC model, including reference SOC stocks, land
use/management activity data, and management factors. Change in C
storage was estimated using a Monte-Carlo approach with 50 000
iterations, by randomly selecting values from the PDFs after
accounting for dependencies in the model inputs. Over the inventory
period, mineral soils had a net gain of 10.8 Tg C yr(-1), with a
95% confidence interval ranging from 6.5 to 15.3 Tg C yr(-1). Most
of this gain was due to setting-aside lands in the Conservation
Reserve Program. In contrast, managed organic soils lost 9.4 Tg C
yr(-1), with a 95% confidence interval ranging from 6.4 to 13.3 Tg
C yr(-1). Combining these gains and losses in SOC, US agricultural
soils accrued 1.3 Tg C yr(-1) due to land use and management
change, with a 95% confidence interval ranging from a loss of 4.4
Tg C yr(-1) to a gain of 6.9 Tg C yr(-1). Most of the uncertainty
was attributed to management factors for tillage, land use change
between cultivated and uncultivated conditions, and C loss rates
from managed organic soils. Based on the uncertainty, we are not
able to conclude with 95% confidence that change in US agricultural
land use and management between 1982 and 1997 created a net C sink
for atmospheric CO2.
© Thomson ISI
21. Agricultural sedimentation impacts on
lakeside property values.
Bejranonda, S.; Hitzhusen, F. J.;
and Hite, D.
Agricultural and Resource
Economics Review 28
(2): 208-218. (1999)
NAL Call #:
HD1773.A2N6; ISSN: 1068-2805
This citation is provided courtesy
of CAB International/CABI Publishing.
22. Agriculture and dynamics of soil erosion
in the United States.
Uri, Noel D and Lewis, James
A
Journal of Sustainable
Agriculture 14 (3): 63-82.
(1999)
NAL Call #:
S494.5.S86S8; ISSN: 1044-0046
Descriptors:
Soil erosion---United States/ Soil
conservation---United States/ United States---Agricultural
policy---Environmental aspects/ Agriculture---Environmental
aspects/ United States---Environmental policy
Abstract: Examines soil conservation programs'
effectiveness in reducing erosion; educational, technical and
financial assistance, research and development, land retirement,
regulation, tax, and incentives policies meant to affect production
practices adoption. Some focus on the Food Security Act of 1985,
the Federal Agriculture Improvement and Reform Act (FAIR) of 1996,
and the Conservation Reserve Program (CRP).
© 2004 PAIS, published by OCLC
Public Affairs Information Service
23. Assessment of soil quality in Conservation
Reserve Program and wheat-fallow soils.
Staben, M. L.; Bezdicek, D. F.;
Smith, J. L.; and Fauci, M. F.
Soil Science Society of
America Journal 61
(1): 124-130. (1997)
NAL Call #:
56.9-So3; ISSN: 0361-5995 [SSSJD4]
Descriptors:
soil/ quality/ assessment/ land
use/ land diversion/ grassland soils/ agricultural soils/ wheat
soils/ soil organic matter/ carbon/ nitrogen content/ carbon
nitrogen ratio/ soil flora/ soil fauna/ biomass/ soil enzymes/
enzyme activity/ soil ph/ mineralization/ respiration/ soil
management/ Washington/ soil respiration
Abstract: Chemical and microbial aspects of soil
quality are an important consideration when evaluating the benefits
of soil conservation efforts such as the Conservation Reserve
Program (CRP). The objective of this study was to evaluate the
quality of CRP and wheat-fallow (W-F) soils using soil biological
and chemical parameters and C and N mineralization processes. The
study was conducted on 20 CRP/W-F paired sites in eastern
Washington, on Ritzville silt loam (coarse-silty, mixed, mesic
Calciorthidic Haploxerolls). Soils collected from the paired fields
were analyzed for chemical and biological parameters that have been
suggested as indicators of soil quality. Potential enzyme
activities and soil N were higher in the CRP soil than the W-F
soil. Although there were no significant differences in total
organic carbon (TOC) or microbial biomass carbon (MBC) the C
mineralization potentials and C pools were significantly different
between the CRP and W-F soils. Soil biota measurements showed there
was greater active bacterial biomass in the CRP soil but greater
fungal-feeding nematodes, flagellates, and amoebae in the W-F soil.
The C mineralization study suggests that there is a significant
increase in the secondary C pool of the CRP soil, which may
indicate a buildup of higher quality soil organic matter and the
potential for higher enzyme levels. When grass or straw was added
to each soil type, the W-F soil produced more CO2 with either
substrate than the CRP soil, indicating C limiting conditions in
the W-F soil. Since it is unknown what constitutes good soil
quality, these shifts in chemical and biological parameters may
seem subtle. However, in general, trends in the data indicated that
soil quality in the CRP was improved after 4 to 7 yr, compared with
its previous management in W-F cropland.
This citation is from
AGRICOLA.
24. Assessment of soil quality in fields with
short and long term enrollment in the CRP.
Baer, S. G.; Rice, C. W.; and
Blair, J. M.
Journal of Soil and Water
Conservation 55
(2): 142-146. (2000)
NAL Call #:
56.8 J822
This citation is provided courtesy
of CAB International/CABI Publishing.
25. Comparing performance of the 1985 and the
1990 Conservation Reserve Programs in the West.
Young, D.; Bechtel, A.; and
Coupal, R.
Journal of Soil and Water
Conservation 49
(5): 484-487. (1994)
NAL Call #:
56.8 J822; ISSN: 0022-4561
Descriptors:
soil conservation/ government
supports/ cropland/ cost analysis/ environmental effects/ policy
making/ soil management/ Western/ erosion control/ government
programs/ economics/ environmental impact/ United States/ Watershed
protection/ Environmental action/ Conservation/ United
States
Abstract: Despite its widespread popularity, the
Conservation Reserve Program (CRP) has been criticized for its cost
ineffectiveness in achieving soil conservation goals. The objective
of this study was to compare how the more targeted revision of the
CRP in the 1990 Farm Bill compares with the 1985 Farm Bill CRP in
concentrating enrollment in highly erodible western U.S. counties.
Correlations between CRP enrollment and erodibility for counties in
California, Idaho, Oregon, and Washington show that the 1990 CRP
has been more successful than the 1985 CRP in concentrating
enrollment in erodible counties. Fixed bid caps in the 1985 CRP
often directed enrollment to counties with lower productivity and
modest erodibility, which reduced cost-effectiveness. While the
1990 reforms appear to have improved the targeting of the CRP, the
1 million ha (2.3 million ac) 1990 CRP is small in terms of
economic and environmental impact compared to the 14 million ha (34
million ac) 1985 CRP.
© Cambridge Scientific Abstracts
(CSA)
26. Conservation Reserve Program effects on
soil quality indicators.
Karlen, D. L.; Rosek, M. J.;
Gardner, J. C.; Allan, D. L.; Alms, M. J.; Bezdicek, D. F.; Flock,
M.; Huggins, D. R.; Miller, B. S.; and Staben, M. L.
Journal of Soil and Water
Conservation 54
(1): 439-444. (1999)
NAL Call #:
56.8 J822
Descriptors:
Conservation Reserve Program/ State
conservation programs/ Regional conservation programs/ Iowa/
Minnesota/
North Dakota/
Washington
Abstract: Reviewed soil data from areas in the U.S.
for their responses to the CRP and whether the soil quality
indicators currently used are an accurate measure of ecosystem
responses to CRP.
27. Cost effectiveness and equity aspects of
soil conservation programs in a highly erodible region.
Young, D. L.; Walker, D. J.; and
Kanjo, P. L.
American Journal of
Agricultural Economics 73 (4): 1053-1062. (Nov. 1991)
NAL Call #:
280.8-J822; ISSN: 0002-9092
Descriptors:
erosion/ soil conservation/ cost
effectiveness analysis/ federal programs/ farmers/ agricultural
regions/ economic impact/ social costs/ profits/ integer
programming/ program participants/ Washington/ food security act of
1985/ distribution of costs/ taxpayers mixed integer programming
models/ Whitman County, Washington
Abstract: The Conservation Reserve (CRP) and
Conservation Compliance Programs could divide the soil conservation
burden between farmers and taxpayers. In a highly erodible
southeastern Washington region, however, a uniform region-wide CRP
bid cap and relaxed compliance requirements resulted in little or
no projected burden for farmers in arid, less productive
subregions. In contrast, farmers in a more productive subregion
were projected to bear 50% or more of the costs of soil
conservation. The projected government cost per ton of soil
conserved also increased threefold from the most to the least
productive subregion.
This citation is from
AGRICOLA.
28. Earthworm (Lumbricidae) survey of North
Dakota fields placed in the U.S. Conservation Reserve
Program.
Deibert, E. J. and Utter, R.
A.
Journal of Soil and Water
Conservation 58
(1): 39-45. (2003); ISSN: 0022-4561
This citation is provided courtesy
of CAB International/CABI Publishing.
29. Effects of long-term cropping on chemical
aspects of soil quality.
Eck, H. V. and Stewart, B.
A.
Journal of Sustainable
Agriculture 12
(2/3): 5-20. (1998)
NAL Call #:
S494.5.S86S8; ISSN: 1044-0046
This citation is provided courtesy
of CAB International/CABI Publishing.
30. Enzyme activities in semiarid soils under
Conservation Reserve Program, native rangeland, and
cropland.
Acosta-Martinez, V.; Klose, S.;
and Zobeck, T. M.
Journal of Plant Nutrition
and Soil Science / Zeitschrift fur Pflanzenernahrung und
Bodenkunde 166 (6):
699-707. (2003)
NAL Call #:
384 Z343A; ISSN: 1436-8730.
Notes: Number of References: 39;
Publisher: Wiley-V C H Verlag
Gmbh
Descriptors:
Agriculture/ Agronomy/ specific
enzyme activities/ arylamidase activity/ beta glucosaminidase
activity/ crop rotations/ cotton/ sunflowers/ beta glucosaminidase
activity / microbial biomass/ residue management/ cropping systems/
arylamidase activity/ organic matter/ chloroform fumigation/ cotton
yield/ tillage/ nitrogen
Abstract: There is limited knowledge of biochemical
processes in low carbon content soils of semiarid regions under
different land use and management. This study investigated several
enzyme activities of C, N, P, and S transformations in semiarid
soils with different clay (10-21 %) and sand (59-85%) contents that
were under Conservation Reserve Program (CRP), native rangeland
(NR), and cropland (CL) under sunflowers (Eriophyllum ambiguum
(Gray)), continuous cotton (Gossypium hirsutum L.), or in rotations
with wheat (Triticum aestivum L.) or sorghum (Sorghum bicolor L.)
in West Texas, USA. Soils under CRP and NR showed higher total C
and N contents than cultivated soils under continuous cotton, but
soil pH (6.7-8.4) was not affected by the management or land use
studied. The activities of beta-glucosidase, beta-glucosaminidase,
arylamidase, acid and alkaline phosphatase, phosphodiesterase, and
arylsulfatase (mg product (kg soil)(-1) h(-1)) were lower in CL
under continuous cotton compared to cotton in rotation with other
crops, CRP, and NR. The enzyme activities were also lower when
compared to soils from other regions. Linear regression analyses
indicated positive correlations between enzyme activities and total
C
(r values up to 0.96, P <
0.01). There was a positive relationship between enzyme activities
and total N, but soil pH showed the opposite trend. Enzyme
activities were significantly intercorrelated with r values up to
0.98 (P < 0.001). The specific enzyme activities (mg product (g
organic C)(-1)) were lower in continuous cotton in comparison to
the uncultivated soils (i.e., NR and CRP) reflecting differences in
organic matter quantity and quality due to cultivation. Among the
enzymes studied, the specific activities of beta-glucosidase and
arylamidase showed a more pronounced decrease with increasing soil
depth. In general, soils under CRP or wheat-cotton rotations
revealed higher enzyme activities than soils under the common
agricultural practice for these regions, i.e., continuous cotton
under conventional tillage.
© Thomson ISI
31. Erosion estimates and the effects of land
use changes on soil savings estimates--Insights from the 1992
National Resources Inventory: Benefits.
Kellogg, R. L. and Wallace,
S.
In: Proceedings of the 50th Annual
Meeting of the Soil and Water Conservation Society. (Held 7-9 Aug, 1995 at Des Moines,
Iowa.); pp. 37-38; 1995.
Descriptors:
USA/ natural resources/ erosion
rates/ cropland/ wind erosion/ land use/ sheet erosion/ rill
erosion/ soil conservation/ 1992 National Resources Inventory/
Conservation Reserve Program/ Erosion and sedimentation
Abstract: The 1992 National Resources
Inventory shows that average erosion rates on cropland fell
dramatically during the 10-year period from 1982 to 1992. The sheet
and rill erosion rate fell from an average of 4.1 tons per acre per
year on 421 million acres of cropland in 1982 to 3.1 tons per acre
per year on 382 million acres of cropland in 1992. At the same
time, the average rate of wind erosion fell from 3.3 tons per acre
per year to 2.4 tons per acre per year. The combined wind and water
erosion rate reduction translates to a saving of nearly 1 billion
tons of soil per year, with approximately equal savings arising
from reductions in sheet and rill erosion rates and wind erosion
rates. Of this, about 395 million tons per year is due to the
enrollment of land in the Conservation Reserve Program, 529 million
tons per year is due to improved conservation practices on
croplands acres, 158 million tons per year is due to conversion of
cropland to other uses (such as developed land, pastureland, etc.).
These savings are offset to some extent by an increase in erosion
of 102 million tons per year on noncropland in 1982 converted to
cropland by 1992. The paper includes a detailed breakdown of these
soil savings estimates for eight major field crops-corn, cotton,
soybeans, wheat, potatoes, sorghum, barley, and rice.
© Cambridge Scientific Abstracts (CSA)
32. Erosion potential of a Torrertic
Paleustoll after converting Conservation Reserve Program grassland
to cropland.
Unger, P. W.
Soil Science Society of
America Journal 63
(6): 1795-1801. (1999)
NAL Call #:
56.9-So3; ISSN: 0361-5995 [SSSJD4]
Descriptors:
mollisols/ clay loam soils/ wind
erosion/ water erosion/ erodibility/ grassland soils/ land use/
conversion/ tillage/ soil management/ grasses/ plant residues/
Texas/ grass management
Abstract: Extensive cropland areas were covered by
the Conservation Reserve Program (CRP) in the semiarid southern
Great Plains. Because soils were highly erodible, would erosion
again become a problem when CRP land was converted to cropland? The
erosion potential due to tillage methods used to convert CRP
grassland to cropland was determined on Pullman clay loam
(Torrertic Paleustoll). Tillage methods were no-, sweep, disk, and
moldboard + disk tillage with CRP grass retained or removed (mowing
and baling), and grass burning followed by sweep or disk tillage.
Wind erosion potential was based on percentage of > 0.84-mm
diam. and mean weight diameter (MWD) of dry aggregates at 2 to 3 yr
after converting to cropland. Water erosion potential was based on
MWD and percentage of < 0.25-mm water-stable aggregates, and
water stability of 1-to 2-mm aggregates at crop planting and
harvest. Few differences due to tillage methods were significant.
For dry aggregates, more than 60% were > 0.84-mm diam. and MWD
was >10 mm with all tillage methods, indicating a low wind
erosion potential. Wet aggregate stability and MWD values at some
sampling times indicated water erosion could occur. Although
erosion potential was low, continued use of residue-incorporating
tillage could lead to greater potentials. Because of initially low
potentials, CRP land on Pullman and similar soils could be
converted to cropland by any tillage method. Then, a conservation
tillage system (e.g., no-tillage) could be implemented before
erosion by wind or water became a serious problem.
This citation is from
AGRICOLA.
33. Establishment of range plants in the
northern Great Plains.
Reis, R. E.; White, R. S.; and
Lorenz, R. J.
In: General Technical Report
RM.
Fort Collins, Colo.: Rocky
Mountain Forest and Range Experiment Station, 1988; pp.
29-34.
Notes: Report Series ISSN: 0277-5786; Proceedings of a
Symposium on "Impacts of the Conservation Reserve Program in the
Great Plains," held Sept 16-18, 1987, Denver, Colorado. Includes
references.
NAL Call #: aSD11.A42
Descriptors:
resource conservation/ soil
conservation/ legislation/ replanting/ northern plains states of
USA/ food security act of 1985/ Conservation Reserve
Program
This citation is from
AGRICOLA.
34. Evaluating Agricultural Nonpoint-Source
Pollution Programs in Two Lake Erie Tributaries.
Forster, D. L. and Rausch, J.
N.
Journal of Environmental
Quality 31 (1): 24-31. (2002)
NAL Call #:
QH540.J6; ISSN: 0047-2425
Descriptors:
Economics/ Agriculture/ Nonpoint
pollution/ Soil erosion/ Water pollution control/ Water
conservation/ Government programs/ tributaries/ Costs/ Performance
assessment/ Governments/ Erosion control/ Pollution control/
Agricultural pollution/ North America, Erie L/ United States,
Maumee River/ United States, Ohio, Sandusky River/ Agricultural
Watersheds/ Nonpoint Pollution Sources/ Best Management Practices/
Government Supports/ Expenditures/ Economic Evaluation/ Economic
Efficiency/ Catchment areas/ Erosion/ Pollution (Nonpoint sources)/
United States, Erie L/ United States, Ohio, Sandusky River/ United
States, Ohio, Maumee River/ Environmental action/ Prevention and
control/ Watershed protection/ Water Quality/ Water Pollution:
Monitoring, Control & Remediation/ Water quality
control
Abstract: During the past three decades, numerous
government programs have encouraged Lake Erie basin farmers to
adopt practices that reduce water pollution. The first section of
this paper summarizes these state and federal government
agricultural pollution abatement programs in watersheds of two
prominent Lake Erie tributaries, the Maumee River and Sandusky
River. Expenditures are summarized for each program, total
expenditures in each county are estimated, and cost effectiveness
of program expenditures (i.e., cost per metric ton of soil saved)
are analyzed. Farmers received nearly $143 million as incentive
payments to implement agricultural nonpoint source pollution
abatement programs in the Maumee and Sandusky River watersheds from
1987 to 1997. About 95% of these funds was from federal sources. On
average, these payments totaled about $7000 per farm or about $30
per farm acre (annualized equivalent of $2 per acre) within the
watersheds. Our analysis raises questions about how efficiently
these incentive payments were allocated. The majority of
Agricultural Conservation Program (ACP) funds appear to have been
spent on less cost-effective practices. Also, geographic areas with
relatively low (high) soil erosion rates received relatively large
(small) funding.
© Cambridge Scientific Abstracts
(CSA)
35. An ex post evaluation of the conservation
reserve, federal crop insurance, and other government programs:
Program participation and soil erosion.
Goodwin, B. K. and Smith, V.
H.
Journal of Agricultural and
Resource Economics
28 (2): 201-216. (2003)
NAL Call #:
HD1750.W4; ISSN: 0162-1912
This citation is provided courtesy
of CAB International/CABI Publishing.
36. Impacts of tillage and no-till on
production of maize and soybean on an eroded Illinois silt loam
soil.
Hussain, I.; Olson, K. R.; and
Ebelhar, S. A.
Soil and Tillage
Research 52 (1/2): 37-49.
(1999)
NAL Call #:
S590.S48; ISSN: 0167-1987
This citation is provided courtesy
of CAB International/CABI Publishing.
37. Integrated dryland crop and livestock
production systems on the Great Plains: Extent and
outlook.
Krall, J. M. and Schuman, G.
E.
Journal of Production
Agriculture 9 (2):
187-191. (Apr. 1996-June 1996)
NAL Call #:
S539.5.J68; ISSN: 0890-8524 [JPRAEN].
Notes: Paper presented at the symposium "Cropping
Systems of the Great Plains" held during the ASA-CSSA-SSSA annual
meetings 1994, Seattle.
Includes references.
Descriptors:
dry farming/ sustainability/
farming systems/ integrated systems/ livestock farming/ crop
production/ land use/ censuses/ trends/ environmental impact/ soil
organic matter/ farm management/ soil fertility/ great plains
states of USA
Abstract: Soil organic carbon levels have declined
24 to 60% on many Great Plains soils since initial cultivation.
Integrated crop and livestock systems could help reverse this
trend, therefore we examined the extent of use, the factors
affecting use, and the potential for this system. The 1992 U.S.
Department of Commerce data indicate that land in integrated
systems is limited to less than 10% of the agricultural land.
However, expiration of the USDA Conservation Reserve Program (CRP)
has created interest in integrated systems. Economists report that
after CRP contracts expire, perennial forages and livestock systems
may be the most profitable; however, a survey of growers indicates
that 63% of all CRP acres will go back to crop production. Recent
research in Wyoming shows that returning CRP land to production
using wheat (Triticum aestivum L.)-fallow practices quickly
degrades soil quality. A doubling of grazing fees would mean an 18%
reduction in demand for public land, which could mean more options
for CRP acreage after contract expiration. Exemplified successful
systems are the Australia wheat-sheep (Ovis aries L.) system,
perennial legume-wheat rotation in southern Alberta, grass
community establishment on marginal Wyoming cropland, and an
alternative (organic) farming system in South Dakota. Benefits
include the opportunity for soil quality improvement, economic
diversity, and pest control. However, tradition, lack of managerial
experience, and necessary alteration in farm-ranch infrastructure
may slow adoption. Generally, dryland integrated systems are
agriclimatic zone specific, and represent a potential ecologically
and economically sustainable form of agriculture. Scientists and
producers have to identify and develop appropriate integrated
systems that fit the natural resource base.
This citation is from
AGRICOLA.
38. Land use biodiversity index as a soil
quality indicator.
Bloodworth H; Sobecki T; and
Santen E van.
In: Making conservation tillage
conventional: Building a future on 25 years of research --
Proceedings of 25th Annual Southern Conservation Tillage Conference
for Sustainable Agriculture. (Held 24 Jun 2002-26 Jun 2002 at Auburn,
AL.); pp. 219-221; 2002.
This citation is provided courtesy
of CAB International/CABI Publishing.
39. Land-use management using a soil survey
geographic database for Finney County, Kansas.
Wu, J.; Ransom, M. D.;
Kluitenberg, G. J.;
Nellis, M. D.; and Seyler, H.
L.
Soil Science Society of
America Journal 65
(1): 169-177. (2001)
NAL Call #:
56.9-So3; ISSN: 0361-5995 [SSSJD4]
Descriptors:
land use / geographical information
systems/ databases/ soil surveys/ land management/ land use
planning/ aquifers/ thickness/ land banks/ remote sensing/
satellite imagery/ fallow/ grasslands/ physiographic features/ soil
organic matter/ soil texture/ surface layers / ground cover/
agricultural land/ crop production/ triticum aestivum/ sorghum
bicolor/ zea mays/ medicago sativa/ horizons/ irrigated farming/
maps/ Kansas/ Conservation Reserve Program/ land cover/ land
use/
land cover maps
Abstract: The determination of best management
practices for land resources is often complicated by the lack of a
means for evaluation and lack of quality data. Soil surveys are an
important source of data that can be used to improve farm and ranch
planning and environmental protection. In this study, we examined
the use of a soil survey geographic (SSURGO) database within a
geographic information system (GIS) coupled with remote sensing
data for land-use management in Finney County, Kansas. The
objectives were (i) to identify land-use change; (ii) to evaluate
the influence of soil, groundwater, and physiography on land use;
and (iii) to assess land-use potential and present management
alternatives. Land-use/land-cover (LULC) maps for 1987, 1989, and
1992 were derived from Landsat Thematic Mapper data. These LULC
layers were manipulated with layers: organic matter content,
thickness, and texture of the surface soil horizon; land capability
class; aquifer thickness (AT); and physiography. The acreage of
fallow land decreased and the acreage of grassland increased from
1987 to 1992 because of an increase in the acreage of land used in
the Conservation Reserve Program (CRP). Broad cropping patterns
(irrigated vs. nonirrigated) did not change significantly between
1987 and 1992 and were related to AT. Some currently cropped areas
had high erosion potential, whereas some grasslands had relatively
low erosion hazards. These grasslands could be used as alternatives
for cropping. The study demonstrates the potential of using SSURGO
within a GIS coupled with remote sensing information in planning
and management for natural resources.
This citation is from
AGRICOLA.
40. Legume, grass, and Conservation Reserve
Program effects on soil organic matter recovery.
Robles, M. D. and Burke, I.
C.
Ecological
Applications 7 (2): 345-357.
(1997)
NAL Call #:
QH540.E23; ISSN: 1051-0761
Descriptors:
United States, Wyoming/ legumes/
grasses/ soil conservation/ organic matter/ Reclamation
Abstract: Active pools of soil organic matter (SOM)
can recover to native levels on formerly cultivated fields that are
abandoned for approximately 50 yr, but the short-term (<10 yr)
recovery dynamics of SOM and nutrient supply have not been widely
investigated. In several fields on a farm in southeastern Wyoming
that had been involved in the Conservation Reserve Program (CRP, a
federal program that pays landowners to convert cultivated land
into revegetated grasslands), we compared C and N in several SOM
pools (coarse particulate organic matter [POM, between 500 mu m and
2 mm], fine POM [53-500 mu m], and total SOM), and we compared
potential C and N mineralization in active pools responsible for
nutrient supply. The two CRP treatments, planted 6 yr prior to this
study, were an approximately 80% legume:20% grass mixture (HL CRP)
and a 20% legume:80% grass mixture (LL CRP). To quantify SOM
accumulations directly due to increased plant inputs within CRP
fields, we also compared SOM pools under legumes and grasses
relative to plant interspaces, where we expected plant inputs to be
minimal. The net impacts of increased plant inputs and the
cessation of tillage generally increased pools of mineralizable and
coarse-POM C and N by factors of two to four relative to
wheat-fallow fields (alternate years in winter wheat and in
fallow), but had negligible effects on total SOM. Recovery of
microsite (approximately 10-cm scale) soil heterogeneity, an
important structural attribute of native arid and semiarid
ecosystems, was accelerated under legumes, which produced more
labile tissue than grasses. Soils under legumes contained larger
pools of coarse-POM C and N and exhibited higher net N
mineralization rates than soil under grasses or in plant
interspaces. Grasses grown in HL CRP soils, which had the highest
rates of potential net N mineralization, produced more labile
tissue than the same grasses grown in the more nutrient-depleted LL
CRP fields, suggesting that plant/soil feedbacks were important.
Therefore, recovery of labile soil and plant N was enhanced when
the proportion of legumes was high, and this may lead to improved
grain or animal N nutrition if these CRP fields are subsequently
cropped or grazed.
© Cambridge Scientific Abstracts
(CSA)
41. Management considerations for returning
CRP lands to crop production.
Lindstrom, M. J.; Schumacher, T.
E.; and Blecha, M. L.
Journal of Soil and Water
Conservation 49
(5): 420-425. (1994)
NAL Call #:
56.8 J822; ISSN: 0022-4561
Descriptors:
soil conservation/ agriculture/
erosion control/ government supports/ cropland/ soil management/
crop production/ government programs / crops/ Watershed protection/
Environmental action
Abstract: The Conservation Reserve Program (CRP)
was initiated in 1985 under the Food Security Act with the
intention of converting up to 18 million hectares (45 million
acres) of highly erodible land (HEL) to permanent cover. Twelve
sign-up periods has resulted in 377,000 contracts nationally. Eight
percent of the cropland in the U.S. is enrolled in CRP. By 1993,
14.8 million hectares (36.5 million acres) of highly erodible or
environmentally sensitive land were enrolled in CRP. The first
contracts will begin to expire in 1995. By 1997, 8.9 million
hectares (22 million acres) will be released from their CRP
contracts. Fifty-five percent of CRP acres (8.1 million hectares or
20 million acres) are located in the 10 Great Plains States.
Average erosion reduction is estimated to be 42.6 Mg ha
super(-1)/yr (19 t/ac) for land enrolled in CRP. As the year 1995
nears and CRP lands become eligible for release, landowners will be
faced with many options, including leaving the lands in grass for
hay or livestock production, or establishing some type of wildlife
or recreation practices. However, recent surveys show that many
acres will be cropped if CRP contracts are not renewed. As global
concern about soil degradation increases, landowners will be
directed toward maintaining the environmental benefits of
CRP,
even on land returning to crop
production.
© Cambridge Scientific Abstracts
(CSA)
42. Microbial diversity along a transect of
agronomics zones.
Ibekwe, A. M.; Kennedy, A. C.;
Frohne, P. S.; Papiernik, S. K.; Yang, C. H.; and Crowley, D.
E.
FEMS Microbiology
Ecology 39 (3):
183-191. (Mar. 2002)
NAL Call #:
QR100.F45; ISSN: 0168-6496 [FMECEZ]
Descriptors:
soil management/ soil flora/ soil
bacteria/ community ecology/ precipitation/ Washington/ ammonia
oxidizing bacteria/ soil quality
Abstract: The diversity of microbial communities
constitutes a critical component of good soil-management practices.
To characterize the effects of different management practices,
molecular indicators such as phospholipid fatty acid (PLFA),
denaturing gradient gel electrophoresis (DGGE) and composition of
ammonia-oxidizing bacteria were used to analyze bacterial community
structure and diversity from four eastern Washington State soils.
Samples from four sites were collected representing a transect of
high-precipitation to low-precipitation areas that covered
different agronomic zones with different management and cropping
practices. Biomass amounts estimated from extractable PLFA were
significantly higher in the no-till (NT) soil than in the
conventional-till (CT) soil. Similarities among the different 16S
rDNA DGGE band profiles were analyzed quantitatively using
correspondence analysis and this confirmed that the CT soil was the
most dissimilar soil. DGGE analysis of 16S rDNA ammonia-oxidizing
bacteria from the four soils revealed two identical bands,
indicating little effect of agronomic practices and precipitation
on these species. A second set of primers, specific for amoA
(ammonia monooxygenase) genes, was used to examine ammonia
oxidizers in the samples. Six banding patterns (clusters) from
amplified rDNA restriction analysis of 16S rDNA fragments were
observed after restriction analysis with HinfI. Sequencing of these
clones revealed the presence of only Nitrosospira-like sequences.
Analysis of the sequences showed that ammonia oxidizers from the NT
soil were more diverse compared to those from the CT and
Conservation Reserve Program soils. Our data showed that management
and agronomic practices had more impact on bacterial community
structure than annual precipitation.
This citation is from
AGRICOLA.
43. A note on the use of conservation
practices in U.S. agriculture.
Boyd, R. and Uri, N. D.
Environmental Monitoring
and Assessment 72 (2):
141-178. (Nov. 2001)
NAL Call #:
TD194-.E5; ISSN: 0167-6369 [EMASDH]
Descriptors:
agriculture/ conservation tillage/
conservation/ agricultural production/ productivity/ carbon/ soil
organic matter/ federal programs/ economic sectors/ mathematical
models/ United States/ carbon sequestration/ Conservation Reserve
Program/ conservation buffer strips/ dynamic computable general
equilibrium models
This citation is from
AGRICOLA.
44. On-site and off-site impacts of soil
erosion: Their implications for soil conservation
policy.
Segarra, E.; Ervin, R. T.; Dicks,
M. R.; and Taylor, D. B.
Resources, Conservation and
Recycling 5 (1): 1-19.
(1991); ISSN:
0921-3449
Descriptors:
erosion/ conservation/ federal
policies/ environmental management/ soils/ Land pollution/
Landslides and erosion/ Environment
Abstract: Using dynamic optimization modeling,
impacts of the Conservation Reserve Program (CRP) and the
Conservation Compliance Provision (CC) contained in the
Conservation Title of the 1985 US Food Security Act was evaluated
for a representative farm in South-Central Virginia. Results
provide insights on the optimal course of action with respect to
what, how, and when to produce agricultural commodities, such that
maximization of net present value of returns is achieved when
considering the alternatives of enrolling in CRP, meeting CC
requirements, or neither.
© Cambridge Scientific Abstracts
(CSA)
45. Post-contract land use effects on soil
carbon and nitrogen in conservation reserve grasslands.
Dao, T. H.; Stiegler, J. H.;
Banks, J. C.; Boerngen, L. B.; and Adams, B.
Agronomy Journal
94 (1): 146-152.
(Jan. 2002-Feb. 2002)
NAL Call #:
4-AM34P; ISSN: 0002-1962 [AGJOAT]
Descriptors:
bothriochloa ischaemum/ triticum
aestivum/ land use/ soil fertility/ nitrogen/ soil organic matter/
grasslands/ nature reserves/ nature conservation/ erosion/
cultivation/ semiarid zones/ tillage/ conservation tillage/
no-tillage/ mineralization/ land banks/ Oklahoma
Abstract: Carbon and N changes in highly erodible
croplands (HELs) under the Conservation Reserve Program (CRP) and
the effects of reverting to cultivation in semiarid regions are not
well understood. The effects of four transitional production
systems [Old World bluestem (Bothriochloa ischaemum
L.)-unfertilized (OWBUF), Old World bluestem-fertilized (OWBF),
conservation-tillage (CT), and no-till (NT) wheat (Triticum
aestivum L.)] on soil C and N were determined in two CRP fields in
western Oklahoma. Soil potentially mineralizable C (PMC) and N
(PMN) were determined in cores collected before and after the
reinitiation of cultivation in 1994 and in 1997. Compared with
soils of the same series from adjoining cultivated fields, Old
World bluestem (OWB) cover increased soil PMC, primarily in the 0-
to 0.1-m depth of Dalhart (Aridic Haplustalfs) and La
Casa-Aspermont (Typic Paleustolls) soils before 1994. Negative PMN
required a high level of fertility management to improve stand
productivity. Shift from OWB to wheat increased soil PMC and PMN in
the short-term. No-till and CT treatments had PMC averaging 8.9 and
9.6 g m(-3) d(-1) or 23 to 32% higher than those from OWB
treatments in the 0- to 0.3-m depth of Dalhart soil. Soil PMC of
the CT treatment averaged 7.2 g m(-3) d(-1) or 73% higher than that
of the La Casa-Aspermont under OWB. The trend of higher
mineralizable C and N suggested that post-CRP conservation
practices, in particular NT, contributed to HEL restoration by also
controlling the upward movement and loss of CO3-C, maintaining
these lands as C sinks in semiarid regions.
This citation is from
AGRICOLA.
46. Properties and productivity of recently
tilled grass sod and 70-year cultivated soil.
Zobeck, T. M.; Rolong, N. A.;
Fryrear, D. W.; Bilbro, J. D.; and Allen, B. L.
Journal of Soil and Water
Conservation 50
(2): 210-215. (1995)
NAL Call #:
56.8 J822; ISSN: 0022-4561
Descriptors:
cultivated lands/ soil erosion/
productivity/ grasslands/ trees/ soil physical properties/
cropland/ erosion control/ Conservation Reserve Program/ Watershed
protection
Abstract: The 1985 Food Security Act established
the Conservation Reserve Program (CRP) whereby highly erodible land
was placed into sod or trees for 10 years. Detailed information on
the effects of grass sod on soil properties and productivity is
needed in order to fully understand the impact of returning the
retired land to production. In this study, land that had been in
grass sod for about 30 years was converted to cotton and sorghum
production in 1985. Yields were measured from 1985 through 1991 on
that land and land that was continuously cultivated for 70 years.
Selected soil properties were also measured after the study. Silt
content, organic matter, and wet soil stability were higher in the
surface soil of the grass sod than in the cultivated fields. Clod
density was lower in the grass sod than in the cultivated fields.
Sorghum biomass was higher in the recently converted field but
yield differences between the converted and continuously cultivated
field were not observed after fertilization. Cotton lint yields did
not increase on the recently converted grassland. These results
suggest economists must consider the crop grown when estimating
yields of crops grown on land previously in the CRP. Crops may
differ in yield and how they respond to management after
conversion.
© Cambridge Scientific Abstracts
(CSA)
47. Restoration of microbial residues in soils
of the Conservation Reserve Program.
Amelung, W.; Kimble, J. M.; Samson
Liebig, S.; and Follett, R. F.
Soil Science Society of
America Journal 65
(6): 1704-1709. (2001)
NAL Call #:
56.9-So3; ISSN: 0361-5995 [SSSJD4]
Descriptors:
land banks/ arable soils/ grassland
soils/ agricultural land/ soil flora/ biomass/ nitrogen content/
carbon/ amino sugars/ chemical composition/ carbon nitrogen ratio/
soil organic matter/ soil conservation/ great plains states of USA/
western states of USA/ Minnesota
Abstract: To elucidate the role of microorganisms
for C and N sequestration in arable soils converted to grassland
(sites of the Conservation Reserve Program; CRP), we determined
amino sugars as indicators for microbial residues in surface
samples (0-5 cm) obtained from each of 10 adjacent native
grassland, CRP, and cropland sites across the U.S. Great Plains.
The CRP sites were 6 to 10 yr and the cropland sites were >80 yr
old. Compared with native grasslands, the CRP sites had lost
between 17 and 50% and the cropland sites between 32 and 94% of
their surface soil organic matter (SOM). The C/N ratio was not
significantly different among the three land-use systems,
indicating that C and N losses occurred at similar intensity. The
mean amino sugar concentrations decreased in the order native
grassland (70 g kg(-1) C; 750 g kg(-1) N) > CRP (53 g kg(-1) C;
570 g kg(-1) N) > cropland (47 g kg(-1) C; 450 g kg(-1) N). This
decrease in the element-normalized concentrations of amino sugars
indicated that they responded faster to management than other C or
N containing compounds. The response of individual amino sugars
related to soil compaction and the temperature regime. We suggest
that the resequestration of C and N into the residues of bacteria
and fungi requires several years, but as it depends on land use it
could be manipulated using, for example, soil decompacting
techniques to improve CRP efficiency.
This citation is from
AGRICOLA.
48. Soil C and N changes on Conservation
Reserve Program lands in the central Great Plains.
Reeder, J D; Schuman, G E; and
Bowman, R A
Soil and Tillage
Research 47 (3-4): 339-349.
(1998)
NAL Call #:
S590.S48; ISSN: 0167-1987
Descriptors:
carbon/ soil storage/ nitrogen/
soil change/ Conservation Reserve Program lands/ crop management/
fallow/ soil technology/ crop (Angiospermae)/ wheat (Gramineae)/
Monocots/ Plants/ Spermatophytes/ Vascular Plants
Abstract: The Conservation Reserve Program (CRP)
was initiated to reduce water and wind erosion on marginal, highly
erodible croplands by removing them from production and planting
permanent, soil-conserving vegetation such as grass. We conducted a
field study at two sites in Wyoming, USA, in order to quantify
changes in soil C and N of marginal croplands seeded to grass, and
of native rangeland plowed and cropped to wheat-fallow. Field plots
were established on a sandy loam site and a clay loam site on
wheat-fallow cropland that had been in production for 60+ years and
on adjacent native rangeland. In 1993, 6 years after the study was
initiated, the surface soil was sampled in 2.5 cm depth increments,
while the subsurface soil was composited as one depth increment.
All soil samples were analyzed for total organic C and N, and
potential net mineralized C and N. After 60+ years of cultivation,
surface soils at both study sites were 18-26% lower (by mass) in
total organic C and N than in the A horizons of adjacent native
range. Six years after plowing and converting native rangeland to
cropland (three wheat-fallow cycles), both total and potential net
mineralized C and N in the surface soil had decreased and NO3-N at
all depths had increased to levels found after 60+ years of
cultivation. We estimate that mixing of the surface and subsurface
soil with tillage accounted for 40-60% of the decrease in surface
soil C and N in long-term cultivated fields; in the short-term
cultivated fields, mixing with tillage may have accounted for
60-75% of the decrease in C, and 30-60% of the decrease in N. These
results emphasize the need to evaluate C and N in the entire soil
solum, rather than in just the surface soil, if actual losses of C
and N due to cultivation are to be distinguished from vertical
redistribution. Five years after reestablishing grass on the sandy
loam soil, both total and potential net mineralized C and N in the
surface soil had increased to levels equal to or greater than those
observed in the A horizon of the native range. On the clay loam
soil, however, significant increases in total organic C were
observed only in the surface 2.5 cm of N-fertilized grass plots,
while total organic N had not significantly increased from levels
observed in the long-term cultivated fields.
© Thomson
49. Soil erosion potential of former
Conservation Reserve Program sites.
Gilley, J. E. and Doran, J.
W.
Transactions of the
ASAE 41 (1):
97-103. (Jan. 1998-Feb. 1998)
NAL Call #:
290.9-Am32T; ISSN: 0001-2351 [TAAEAJ]
Descriptors:
erodibility/ water erosion/
estimation/ simulation models/ computer simulation/ conservation
areas/ soil conservation/ federal programs/ land use/ universal
soil loss equation/ Mississippi/ Nebraska/ South Dakota/ water
erosion prediction project (WEPP)/ revised universal soil loss
equation (RUSLE)
Abstract: Conservation Reserve Program (CRP) areas
that are returned to crop production will initially be much less
erodible than fields which were farmed using conventional
practices. In this study, a rainfall simulator was used to measure
runoff and erosion from former CRP areas in Mississippi, Nebraska
and South Dakota over approximately a two year period. Soil loss
rates measured immediately following tillage on each of the three
sites were similar to values obtained on the undisturbed CRP
treatments. However, when left in a fallow condition, the
erosion-reducing effectiveness of the sod appeared to have lasted
less than one year. The rapid increase in soil erodibility
following tillage was attributed to a reduction in surface cover
and organic material. The WEPP and RUSLE models are currently used
extensively in conservation planning and assessment. The
experimental data collected in this study were used to derive
selected parameter values for use in these models.
This citation is from
AGRICOLA.
50. Soil hydraulic properties of cropland
compared with reestablished and native grassland.
Schwartz, R. C.; Evett, S. R.; and
Unger, P. W.
Geoderma 116 (1-2): 47-60. (2003)
NAL Call #:
S590.G4; ISSN: 0016-7061.
Notes: Number of References: 32
Descriptors:
Agriculture/ Agronomy/ hydraulic
properties/ porosity/ hydraulic conductivity/ soil management/
tillage/ infiltrometers/ unsaturated soils/ tillage/ infiltration/
conductivity/ infiltrometers/ model/ disc
Abstract: Conversion of cropland to perennial
grasses will, over time, produce changes in soil hydraulic
properties. The objective of this study was to characterize and
compare hydraulic properties of fine-textured soils on adjacent
native grassland, recently tilled cropland, and reestablished
grassland in the Conservation Reserve Program (CRP) at three
locations in the Southern Great Plains. A tension infiltrometer was
used to measure unconfined, unsaturated infiltration over a range
of supply pressure heads (nominally, h = -150, -100, -50, and -5 mm
H2O) at the soil surface. Intact soil cores were sampled within the
Ap and Bt horizons to determine bulk density and water desorption
curves, theta(h), at potentials ranging from -0.15 to -100 kPa.
Unsaturated hydraulic conductivity K(h) over the range in supply
pressure heads was estimated using Wooding's equation for
steady-state flow from a disc source. The van Genuchten water
retention model was fitted to theta(h) data to estimate parameter
values. Soils in CRP had greater surface bulk densities than their
grassland and cropland counterparts. The shape of the soil water
retention curve for grassland and CRP land were similar, suggesting
that converted croplands had fully reconsolidated. Mean
near-saturated hydraulic conductivities of cropland at h = -5 mm
were not significantly different from grassland. However, at -150
mm supply pressure head, cropped soils had a mean unsaturated
conductivity 2.3 and 4.1 times greater than CRP land and grassland,
respectively. Sites in CRP had the lowest (P < 0.05)
near-saturated hydraulic conductivities (h = -5 mm), which suggest
that after 10 years, grasses had not fully ameliorated changes in
pore structure caused by tillage. Comparison of unsaturated
conductivities for grassland and CRP land suggest that long-term
structural development on native grasslands was principally
confined to effective pore radii greater than 300 mum. Land use
practices had a greater effect on water movement than did soil
series, indicating that the modifying effects of tillage,
reconsolidation, and pore structure evolution on hydraulic
properties are important processes governing water movement in