ABSTRACT The land use change from cropland to perennial grass cover associated with The Conservation Reserve Program (CRP) may sequester atmospheric CO, back into the soil carbon pool, thereby changing formerly cultivated soils from sources to sinks,for atmospheric carbon. To evaluate the effect of CRP on soil organic carbon (SOC] levels, samples from adjacent cropland, native pasture, and five year old CRP sites in Texas, Kansas, and Nebraska were analyzed. Across all locations, SOC levels for cropland, CRP, and native pasture were 59.2, 65.1, and 90.8 metric tons c-1 ha-1 in the surface 300 cm, respectively. CRP lands gained an average of 1.1 tons C ha-1 yr-1 suggesting that the 17 million hectares of land enrolled in CRP may have the potential to sequester about 45% of the 38. 1 million tons of carbon released annually into the atmosphere from US agriculture. These findings illustrate that agricultural CO2 emissions may be effectively controlled through changes in land use and management systems.
