How grazing lands influence greenhouse gas

May 18, 2010
A steer grazes on a crested wheatgrass pasture at the Northern Great Plains Research Laboratory, Mandan, ND. Credit: Mark A. Liebig

Grazinglands represent one of the largest land resources in the world, yet their role as net sinks or sources of greenhouse gases is essentially unknown. Previous research has emphasized the role of grazing management on the sequestration of atmospheric carbon dioxide as soil organic carbon. However, there is a lack of information regarding how grazing management impacts the flux of two potent GHGs, nitrous oxide and methane.

A team of scientists lead by Mark Liebig at the USDA-ARS Northern Great Plains Research Laboratory estimated net potential for three grazing management systems located in central North Dakota. The grazing management systems represented two native vegetation pastures under medium and high grazing pasture management, and a heavily grazed seeded crested wheatgrass pasture receiving supplemental nitrogen. The results indicate that grazinglands are strong sinks of soil organic carbon and minor sinks of methane, but small to moderate sources of . Results from the study were published in the May-June 2010 issue of Journal of Environmental Quality, published by the America Society of Agronomy, the Crop Science Society of America, and the Soil Science Society of America.

Net global warming potential for the native grasslands was negative, implying an overall removal of greenhouse gases from the atmosphere. This finding underscores the value of grazed, mixed-grass prairie as a viable agroecosystem to serve as a net greenhouse gas sink in the northern Great Plains. Conversely, the seeded forage nitrous oxide emissions were nearly three times that of the native grasses, which contributed a net positive net global warming potential, implying net greenhouse gas emission to the atmosphere.

The research team was able to estimate global warming potential for each management practice by measuring changes in organic carbon, and nitrous oxide and methane flux. This data was combined with estimates for methane emissions from cattle and emissions associated with applying nitrogen fertilizer.

"It's important to keep in mind the greenhouse gas balance we measured for the grazing treatments falls short of encompassing the full life-cycle of a steer," said Mark Liebig. "While our results suggest grazed native vegetation in the northern Great Plains is a net GHG sink, we need to acknowledge there is additional emissions associated with cattle production outside of what we measured or estimated."

Explore further: Measuring phosphorus loss from Midwest crop fields

More information: View the abstract at www.agronomy.org/files/publica… 09-0272-abstract.pdf

Provided by American Society of Agronomy

1 /5 (1 vote)
add to favorites email to friend print save as pdf

Related Stories

Managing carbon loss

Dec 03, 2008

As the United States continues to develop alternative energy methods and push towards energy independence, cellulosic-based ethanol has emerged as one of the most commercially viable technologies. Corn stover remains the ...

Reducing Agriculture's Climate Change Footprint

Nov 04, 2009

(PhysOrg.com) -- Curbing greenhouse gas emissions from cultivated fields may require going beyond cutting back on nitrogen fertilizer and changing crop rotation cycles, according to research by Agricultural ...

Recommended for you

Measuring phosphorus loss from Midwest crop fields

1 hour ago

Field runoff from farms in the Lake Erie basin is often rich in soluble plant nutrients, including phosphorus. When this nutrient-rich runoff reaches the lake, the phosphorus can support abundant algal blooms ...

FACT CHECK: Both sides in Keystone XL debate bend facts

14 hours ago

Supporters of the Keystone XL pipeline, which would run from Canada to the Gulf, say the privately funded, $8 billion project is a critically needed piece of infrastructure that will create thousands of jobs ...

Sao Paulo warns of severe water rationing

16 hours ago

Authorities in Sao Paulo, Brazil's richest state and economic hub, have warned they are considering severe water rationing if the country's worst drought in 80 years continues.

Refineries challenge EPA plan to cut emissions

19 hours ago

A rule proposed by the Environmental Protection Agency that aims to curb emissions from oil refineries and petrochemical manufacturers is causing tensions to flare between the agency and industry groups. The agency is reviewing ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.