Carbon sequestration in agricultural lands of the United States

R educing concentrations of carbon dioxide (CO2) and other greenhouse gases (GHG) in Earth's atmosphere is identified as one of the most pressing modern-day environmental issues (IPCC 2007). As a signatory country to the United Nations Framework Convention on Climate Change (UNFCCC), the United States is actively engaged in a critical international effort to find solutions to the problems posed by climate change. Agriculture, in addition to being affected by the climate, contributes to climate change through its exchanges of GHG with the atmosphere. Thus, the management of agricultural systems to sequester atmospheric CO2 as soil organic carbon (SOC) and to minimize GHG emissions has been proposed as a partial solution to the climate change problem. In this paper, we discuss the potential role of agriculture in the United States to mitigate climate change through sequestration of carbon (C). We also identify critical knowledge gaps where further research is needed. Carbon enters terrestrial ecosystems, including agriculture, through photosynthesis by green plants that assimilate CO2 and fix it into organic forms (figure 1). Some C eventually enters the soil, where its subsequent cycling and storage among SOC and soil inorganic carbon (SIC) pools determine its residence time and ultimately its return back…