S.D. well-managed soils capture carbon
Carbon sinks are natural or artificial reservoirs that accumulate and store some carbon-containing chemical compound for an indefinite period. The process by which carbon sinks remove carbon dioxide from the atmosphere is known as carbon sequestration.
Public awareness of the significance of carbon sinks has grown since passage of the Kyoto Protocol, which promotes their use as a form of carbon offset. A carbon sink ultimately removes carbon dioxide from the environment. Growing levels of greenhouse gasses such as carbon dioxide are thought to cause global warming.
The creation of agricultural-based carbon sinks are attributed to the adoption by farmers of minimum and no-tillage farming practices that were researched and promoted by the College of Agriculture and Biological Sciences at South Dakota State University, and at the USDA's Natural Resource and Conservation Service.
Soil carbon sequestration is influenced by many factors, including the amount of carbon contained in the soil, mineralization rates, tillage and the amount of non-harvested carbon returned to the soil, according to Clay.
"Prior to 1984 our average surface soil organic carbon levels had declined about 60 percent when compared to original values when the land was homesteaded," Malo said. This study documented that over the past 25 years surface carbon amounts have increased due to changing agricultural practices.
The study also found that the partial carbon footprint of corn decreased with increasing sequestered carbon. The study suggests that carbon is being sequestered in many Northern Great Plains surface soils. These results are attributed to: 1) carbon mining that occurred following homesteading, 2) gradual crop yield increases which increased nitrogen holding capacity to the soil; and, 3) wide-scale adoption of reduced tillage and then no-tillage methods. Subsequently, calculations and producer soil samples suggest that surface soils of this region are a carbon sink. The results are different than a general perception that annually cropped soils in the Northern Great Plains are losing carbon. These findings have ramifications relative to water quality and soil resilience.
Barry Dunn, Ph.D., dean of Agriculture and Biological Sciences at South Dakota State University, said the discovery is stunning. "Their unbiased scientific research could change how agriculture is perceived in the world around us."
"But the impacts of this research aren't just about changing perceptions. This work may also have important economic impacts as well. When combined with carbon life-cycle analysis conducted by our research team and researchers at the South Dakota School of Mines and Technology, findings from this research shows that South Dakota farmers have some of the lowest energy footprints in the world. In addition, ethanol produced in South Dakota may meet the California advance renewable fuel standard. Meeting this fuel standard has the potential to dramatically increase the value of South Dakota ethanol in a highly competitive marketplace," Dunn said.
Funding for this critical research was provided by the South Dakota Corn Utilization Council, the South Dakota Soybean Research and Promotion Council, Monsanto, the Agricultural Experiment Station in the College of Agriculture and Biological Sciences at South Dakota State University, the United States Department of Agriculture and the National Aeronautical Space Administration (NASA).