Impact of Livestock Grazing on Carbon and Nitrogen Balance of a Short-grass Steppe
Entry ID:
USDA.ARS.CGPRS.SGSgraze
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Summary
(adapted from project abstract)
Problem: Grazing lands constitute about 55% ofthe total land surface
of the United States, and have been estimated to contain 40,000 MMT of C
in the top 2 m of the soil profile. An increase of only 0.5% in the
organic C in the top 10 cm of grazing land soils is equivalent to the
C emissions from all US cropland ... agriculture (R.F. Follett, personal
communication). However, the potential for these grazed lands to
sequester C is not well understood. Fundamental to an evaluation of
whether grasslands are a source or sink for C is an understanding of1h
.e effects of grazing management strategies on C inputs into the soil
by the plant community, and onthe soil microbial processes that
mediate C cycling in grassland soils.
Approach: We evaluated changes in the distribution of C and N within
the short-grass grass steppe plant:soil system as the result of 55
years ofseason-long grazing at three cattle stocking -I) rates (0, 17
and 37 heifer days per ha). On both the short-grass and mixed grass
systems, we measured CO2 exchange rates to assess photosynthesis
throughout a growing season. (This information is reported in the
USDA/ARS/RRRU/Carbonxchng Directory entry.)
Findings: Long term heavy grazing of the short-grass steppe resulted
in a plant community dominated by warm season grasses with a
root:shoot ratio of 13:1, whereas the plant communities in the
exclosures or under light grazing exhibited larger forb and half-shrub
components and a root:shoot ratio of 5:l. A significant increase in C
sequestered in the soil profile was observed with the heavy stocking
rate. Part of this increase in soil C with heavy grazingis the result
of redistribution of system C because blue grama, the predominant
warm-season grass, transfers more photosynthate below ground than do
the cool-season grasses. However, the increase in soil profile C also
appears to be associated with an apparent significant increase in
ecosystem (plant:soil) C. Higher CO2 exchange rates were observed in
the heavily-grazed pastures in years with warm, dry spring conditions,
which are common on the short-grass steppe and which favor the growth
and photosynthesis of warm season grasses (see
USDA/ARS/RRRU/Carbonxchng DIF). An evaluation is currently underway
ofthe effects ofgrazing intensity on soil microbial activity.
Future Plans: New studies will be initiated in 1999 to evaluate the
effects of elevated CO2, soil texture, and plant species composition on
C fixation by the plant community, and the subsequent flux of plant C
into the soil. These studies will be conducted in growth chambers and
in the open top chambers at the Central Plains Experimental Range,
Nunn CO. Meetings also will be held in the spring, 1999, with
scientists at the Fort Keogh Lab, Miles City MT, to investigate
possible future cooperative research activities. We will evaluate the
feasibility of superimposing biogeochemical C and N cycling studies on
their existing grazing management studies.
Geographic Coverage
Spatial coordinates
Data Set Citation
Dataset Creator:
J.D. Reeder, G.E. Schuman, J.A. Morgan, D.R. LeCain and R.H. Hart
Dataset Title:
Impact oflivestock grazing on carbon and nitrogen balance of a short-grass stepp
Dataset Release Date:
1999
Dataset Release Place:
Ft. Collins, CO
Dataset Publisher:
Rangeland Resources Research Unit, USDA-ARS
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Temporal Coverage
Start Date:
1994-01-01
Stop Date:
1999-01-01
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Location Keywords
Science Keywords
ISO Topic Category
Platform
Quality
data have been peer reviewed
Access Constraints
none
Use Constraints
none
Ancillary Keywords
Data Set Progress
Originating Center
Data Center
Personnel
RICHARD
H.
HART
Role:
INVESTIGATOR
Phone:
(307) 772-2433
Fax:
(307) 637-6124
Email:
rhart at lamar.colostate.edu
Contact Address:
USDA Agricultural Research Service
High Plains Grasslands Research Station
8408 Hildreth Road
City:
Cheyenne
Province or State:
WY
Postal Code:
82009
Country:
USA
DANIEL
R.
LECAIN
Role:
INVESTIGATOR
Phone:
(970) 498-4217
Fax:
(970) 482-2909
Email:
lecain at lamar.colostate.edu
Contact Address:
Rangeland Resources Research Unit, USDA-ARS
CROPS RESEARCH LAB
1701 Center Ave
City:
Fort Collins
Province or State:
CO
Postal Code:
80526-2083
Country:
USA
JACK
A.
MORGAN
Role:
INVESTIGATOR
Phone:
(970) 498-8216
Fax:
(970) 482-2909
Email:
morgan at lamar.colostate.edu
Contact Address:
USDA-ARS Rangeland Resources Research Unit
CROPS RESEARCH LAB
1701 Center Ave
City:
Fort Collins
Province or State:
CO
Postal Code:
80526
Country:
USA
J.
D.
REEDER
Role:
INVESTIGATOR
Role:
TECHNICAL CONTACT
Phone:
(970) 498-4236
Fax:
(970) 482-2909
Email:
jdreeder at lamar.colostate.edu
Contact Address:
USDA-ARS Rangeland Resources Research Unit
CROPS RESEARCH LAB
1701 Center Ave
City:
Fort Collins
Province or State:
CO
Postal Code:
80526-2083
Country:
USA
GERALD
E.
SCHUMAN
Role:
INVESTIGATOR
Phone:
(307) 772-2433
Fax:
(307) 637-6124
Email:
gschuman at lamar.colostate.edu
Contact Address:
High Plains Grasslands Research Station
USDA Agricultural Research Service
8408 Hildreth Road
City:
Cheyenne
Province or State:
WY
Postal Code:
82009
Country:
USA
TYLER
B.
STEVENS
Role:
DIF AUTHOR
Phone:
(301) 614-6898
Fax:
301-614-5268
Email:
Tyler.B.Stevens at nasa.gov
Contact Address:
NASA Goddard Space Flight Center
Global Change Master Directory
City:
Greenbelt
Province or State:
MD
Postal Code:
20771
Country:
USA
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Publications/References
Reeder, J.D., G.E. Schuman, and R.A. Bowman. 1998. Soil carbon and
nitrogen changes in CRP lands in the Central Great Plains. Soil and
Tillage Research. 47:339-349.
Reeder, J.D., G.E. Schuman, J.A. Morgan, D.R. LeCain, and
R.H. Hart. 1998. Impact of livestock grazing on the carbon and
nitrogen balance ofa Shortgrass steppe. Agron. ... Abstracts. p. 291.
Herrick, J.E., M.A. Weltz, J.D. Reeder, G.E. Schuman, and J.R
Simanton. 1998. Rang e land erosion and soil quality. role of soil
resistance, resilience, and disturbanceregimes. pp. 209-233. In:
Rattan Lal (ed.) Soil Erosion and Soil Quality. CRC Press, LLC, Baca
Raton,FL.
LeCain, D.R., J.A. Morgan, G.E. Schuman, J.D. Reeder, and
R.H. Hart. 1998. Cattle grazing and carbon assimilation in the norther
mixed prairie of Wyoming. Agron. Abstracts. p. 293.
Schuman, G.E., J.D. Reeder, J.T. Manley, R.H. Hart, and
W.A. Manley. 1999. Impact ofgrazing management on the carbon and
nitrogen balance ofa mixed-grass rangeland. Ecological
Applications. 9. In press..
Schuman, G.E., J.D. Reeder, J.A. Morgan, R.H. Hart, and
D.R. LeCain. 1998. Carbon and nitrogen balance ofa grazed mixed-grass
prairie in Wyoming, USA. In: 16th WorldCongress of Soil Science,
Montpellier, France.
Creation and Review Dates
Last DIF Revision Date:
1999-09-09
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Links
