Since the late 1800’s fossil fuel use, expansion of cultivated agriculture, and forest clearing have led to an increase in atmospheric CO2 from 260 ppm to current levels >370 ppm. This increase CO2 potentially impacts climate, as it is a greenhouse gas. Approximately 50% of the soil organic carbon (soil organic matter) has been lost from the soil over a period of 50 to 100 years of cultivation. However, this loss of soil carbon also represents the potential for storage of C in the soil. Recent models of land use suggest terrestrial systems can mitigate the increase of atmospheric CO2 by sequestering C into vegetation and soils. Carbon input into soils occurs primarily through plants. It is desirable to sequester C in the soil because it can have residence times, up to 1000y.
Much of the central United States and Canada, which was once prairie, is now in cultivated agriculture. The grasses of prairies store much of their C belowground, which is eventually converted to soil organic carbon. Advancement in crop and soil management practices have the potential to increase soil C. Managing agricultural and rangeland soils for sequestering C, will result in additional benefits. The direct effects of increasing soil organic C include increased crop productivity and enhanced soil, water, and air quality.
OBJECTIVES
To evaluate the long-term impact of tillage and residue management systems on the accumulation of organic C we will utilize the long-term experimental sites located in the region that was formerly tallgrass prairie. Agricultural practices include tillage, residue management, rotations, and fertility
To meet objective 3 we will use expertise in several disciplines to build this multi disciplinary multi institutional team. To gain the most benefit from our research teams on soil C cycling, we will establish a few sites to intensely measure the different components of C inputs and chemical and biological transformations. We will establish field experiments with different tillage and cropping systems to measure C inputs, cycling and outputs.