Opportunities to increase soil carbon sequestration in grazing lands in the southeastern United States

Background:Grazing lands provide numerous ecosystem services,including the capacity to store large amounts of soil carbon(C);however,our understanding of the factors affecting soil C responses to management is inadequate.Methods:In this paper,we synthesized information about the impacts of grazing land management on soil C within the southeastern region of the United States.Results:Most studies(68%)demonstrated that proper management increased soil C stocks with an average C accumulation rate of 1.4 Mg C ha-1 year-1.The remaining(32%)studies showed no effect of management on soil C.None of the studies reported negative impacts of management on soil C.The largest increase in soil C(8 Mg C ha-1 year-1)was associated with the conversion of cropland to pastureland while overseeding legumes into grass pastures resulted in the lowest C sequestration rates(0.2 Mg C ha-1 year-1).Conclusions:Considering the rates of soil C accretion and the extensive area occupied by grazing lands,data in this synthesis confirm that the adoption of improved management practices can increase soil C sequestration in the southeastern United States.In addition,because most improved management practices can also have co-benefits,they may be favorable for forage and livestock production and other ecosystem services.