The Impact of Soil Conservation Policies on Carbon Sequestration in Agricultural Soils of the Central United States

The pool of organic carbon in soils plays a key role in the carbon cycle and has a large impact on the greenhouse effect (Lal et al., 1995). Soils contain an estimated 1.5 x 10¹⁸ g of carbon, or twice as much as the atmosphere and three times the level held in terrestrial vegetation (Post et al., 1990; Schlesinger, 1990). The annual net release of carbon from agriculture has been estimated at 0.8 x 10¹⁵ g, or about 14% of current fossil fuel emissions (Schlesinger, 1995). In addition to the influence that soil carbon has on global warming, it also plays a key role in determining long-term soil fertility necessary to sustain profitable long-term agricultural production. The ability to sequester carbon in soils by proper tillage and erosion management provides long-term justification for soil conservation programs. However, there is scant information on the changes in soil organic carbon (SOC) that accrue from key soil conservation programs and policies.