Which changes in farming practices enable soils to store more carbon?
Cesar Izaurralde and Norm Rosenberg, two of our PNNL partners, are experts in agricultural systems. They point out that soil carbon can be increased by reduced-till agriculture, in which the soil is barely disturbed before crops are planted, and by the practice of returning crop residues to soil to reduce wind erosion. The U.S. Conservation Reserve Program (CRP) of the US Department of Agriculture, which since 1985 has been paying farmers to retire land from cultivation for up to 15 years and plant it in grass to stabilize it, is also increasing soil carbon storage. Some evidence suggests that levels of soil organic carbon have doubled over the past 20 years in the upper 18 centimeters of soil placed in the CRP. In addition, erosion of the land enrolled in the CRP has decreased 21%. All of these practices reflect mainly the “recovery” of soil carbon previously lost because of earlier cultivation. Which changes in forestry practices would make plants and soils more efficiently remove ca
