Carbon (C) sequestration in vegetation and soils has reached international consensus as one technology that could be used to mitigate climate change (IPCC, 2000). Brown et al. (1996) estimated that about 38 Pg C could be sequestered over a 50-year period by implementing afforestation, reforestation, and agroforestry practices over 345 Mha. Likewise, Cole et al. (1997) estimated that 40 Pg C (two-thirds of historical losses of soil organic C [SOC] from agricultural land) could be sequestered in soil over a 50-to 100-year span by applying a suite of improved agricultural practices (e.g., no-till, nutrient management, diversified crop rotations). These potentials appear small relative to the potential of other forms of sequestration (e.g., 2,900 Pg C for geologic sequestration, Dooley et al., 2004). However, terrestrial C sequestration could have an immediate application in climate change mitigation due to its availability, relatively low cost, and associated environmental benefits.