URBANA, Ill. For the past 20 years, researchers have published soil organic carbon sequestration rates. Many of the research findings have suggested that soil organic carbon can be sequestered by simply switching from moldboard or conventional tillage systems to no-till systems. However, there is a growing body of research with evidence that no-till systems in corn and soybean rotations without cover crops, small grains, and forages may not be increasing soil organic carbon stocks at the published rates.
"Some studies have shown that both moldboard and no-till systems are actually losing soil organic carbon stocks over time," said University of Illinois soil scientist Ken Olson who led the review.
The review was conducted by a team of senior researchers from universities in Illinois, Wisconsin, Iowa, and Ohio who studied the published soil science and tillage literature related to soil organic carbon sequestration, storage, retention, and loss.
After examining hundreds of original research and summary papers, 120 papers on all sides of the soil organic carbon sequestration, storage, retention, and loss issue were selected for review and analysis.
Olson explained that the difference between the no-till and moldboard plots at the end of a long-term study is only a measure of net soil organic carbon storage difference between treatments and does not support soil organic carbon sequestration claims.
No-till systems on sloping and eroding sites retain more soil organic carbon in the surface from 0 to 15 centimeters when compared to moldboard as a result of less disturbance and less soil erosion and transport of soil organic carbon-rich sediment off the plots.
"The subsurface layers also need to be sampled and tested to the depth of rooting or 1 or 2 meters," Olson said. "That no-till subsurface layer is often losing more soil organic carbon stock over time than is gained in the surface layer."'/>"/>
|Contact: Debra Levey Larson|
University of Illinois College of Agricultural, Consumer and Environmental Sciences