Manhattan Kansas soil can absorb greenhouse gases, according to a Kansas State University researcher, but there are limits.
The Kansas prairie is proving more resilient to changes in the global atmosphere than once thought.
In fact, according to one researcher at Kansas State University, its ability to absorb excess greenhouse gases like carbon dioxide may buy additional time for the nations of the world to find longer-term solutions to the problem of global warming.
But Charles Rice, a soil microbiologist at K-State conducting the research, also is trying to caution people against drawing too many conclusions from his research.
"What we've been advising is, soils don't have an infinite capacity to store excess carbon," Rice said in a recent interview. "Our estimate is, if we adopt these (improved farming) practices, it will buy us about 50 years more time to develop other technologies and make them economically viable."
The research at K-State and other land grant universities has been going on since about 1989, Rice said, but has started drawing national attention as nations consider a multinational treaty to reduce greenhouse gas emissions.
As part of a federally funded research program, Rice is trying to determine how farmland and the tallgrass prairie in Kansas would respond to elevated levels of carbon dioxide in the atmosphere.
The question is important because for the past 100 years or so, humans have been releasing more carbon dioxide into the atmosphere through agricultural practices and the burning of fossil fuels.
Many scientists believe that is producing a "greenhouse effect," whereby those gases trap heat in the Earth's atmosphere, leading to global warming and changes in global climate.
What Rice has found so far is that the prairie not only withstands elevated levels of carbon dioxide, it actually has the ability to pull carbon out of the air and store it in the ground.
"The prairie has the capacity to absorb (carbon dioxide) into the soil," Rice said. "Parts of the soil carbon can be locked up for a long period of time."
By "long period," Rice is talking about thousands of years, or as long as the grassland is left undisturbed.
The findings could have profound implications for agriculture on the Great Plains, Rice said.
Farming is often cited as one of the leading contributors to the greenhouse effect, in part because plowing up fields disturbs the soil and releases trapped carbon back into the atmosphere.
Irrigation and the spraying of chemical fertilizers can also contribute to the greenhouse effect.
But Rice said his research shows that switching to practices like no-till or reduced-tillage planting could enable the Great Plains to filter more carbon out of the air and delay the effects of greenhouse gases.
Net gain, or catch-up?
Rice readily admits his research does not imply that improved farming practices are the answer to global warming. They can absorb some of the excess carbon humans have put in the atmosphere, but not all of it.
The U.S. Environmental Protection Agency maintains a Web site on global warming, (http://www.epa.gov/oppeoee1/globalwarming), that also indicates there may be only so much agriculture can do to buffer the Earth from global warming.
According to an article posted on that Web site, the plant activity that Rice describes has been part of the Earth's natural balance for thousands of years.
"Plant respiration and the decomposition of organic matter release more than 10 times the (carbon dioxide) released by human activities," the article states, "but these releases have always been in balance with the carbon dioxide absorbed by plant photosynthesis."
What has happened in the past 100 years, the EPA says, is that humans have added large volumes of carbon to the balance by pulling carbon -- oil and coal, for instance -- out of the ground and releasing it into the atmosphere by burning it as fuel.
Rice said his research shows the prairie can absorb some of that additional carbon, but he said the real solution lies in developing other sources of fuel that do not add to the greenhouse effect.
"Bio-fuels, lower-emission fuels, more efficient cars and other technologies like solar power and wind power -- those technologies are there; it's just a matter of getting the economic cost down so they can be accepted," Rice said.
Rice's research has been gaining wider public attention in political circles as the United States and other industrialized nations are being urged to sign the Kyoto Protocol, a multinational treaty calling for the reduction of greenhouse gas emissions worldwide.
That treaty has met with stiff opposition in the United States, particularly from the agribusiness industry, because it could result in higher fuel taxes and other mandates to force agriculture and other industries to cut pollution and reduce fuel consumption.
U.S. Sen. Pat Roberts, R-Kan., a member of the Senate Agriculture Committee, introduced a bill in May calling for more federal funding of the research being conducted at K-State and other land grant universities.
In a statement announcing his bill, Roberts called the Kyoto Protocol "fatally flawed" and said the U.S. should focus its efforts instead on research into agriculture's link to the carbon cycle.
Fellow Kansas Sen. Sam Brownback, also a Republican, said last week that he opposed the treaty because it treats the United States unfairly.
"Provisions of the treaty bind us (to reduce greenhouse gases) but not China, Mexico, India or other countries that are substantially growing in pollution," Brownback said.
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