planted in the residue from the previous cropcorn. Click the image for
more information about it.
No-Till Farming Can Decrease "Global Warming
Potential" By David Elstein
August 31, 2004
Farmers may be able to lower the net rate of the "greenhouse
gases"--known as the "Global Warming Potential"--that their farming systems
emit, according to Agricultural Research
Service scientists and university collaborators.
The scientists found that certain activities, such as switching
to no-till farming, may also increase crop yields while helping the
Some gases in the atmosphere trap heat near the Earth's surface,
much like glass panes trap heat inside a greenhouse. Agricultural systems both
release and absorb certain greenhouse gases. The difference between the total
emission and absorption of these gases helps researchers understand the Global
Plants remove carbon dioxide, an important greenhouse gas, from
the air and convert it to carbon-containing compounds. Eventually, much of that
carbon returns to the soil as crop debris or waste from animals that ate the
plants. Carbon that stays in the soil improves soil conditions for agriculture
and also "sequesters" the gas out of the atmosphere. But crop and animal
residues in and on the soil are decomposed by microbes, releasing the carbon
dioxide back into the air.
Nitrogen fertilizers can be converted by microbes to nitrous
oxide, a potent greenhouse gas. A third greenhouse gas, methane, can be
released or absorbed by soils and is also released by some kinds of livestock
and animal wastes.
Fort Collins, Colo., is one ARS location studying Global Warming
Potential. There, chemist Arvin R. Mosier and soil scientist
Ardell D. Halvorson, of the ARS Soil-Plant-Nutrient
Research Unit, and Gary A. Peterson of
Colorado State University believe
that switching to no-till farming, a system of cultivation
in which the soil is not disturbed, will decrease the Global
Warming Potential on some farms. Soil disturbance stimulates
much of the microbial activity that converts organic matter
and nitrogen fertilizer into the greenhouse gases.
Around the country, ARS scientists are studying how a wide
variety of management practices affect the Global Warming Potential.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.