|Schuman, Gerald - RETIRED ARS SCIENTIST|
Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 21, 2007
Publication Date: April 21, 2007
Citation: Derner, J.D., Schuman, G.E. 2007. Carbon sequestration and rangelands: A synthesis of land management and precipitation effects. Journal of Soil and Water Conservation 62(2):77-85. Interpretive Summary: Proper management of rangelands offers opportunities to partially mitigate the rise in atmospheric carbon dioxide concentrations through sequestration of this additional carbon via storage in biomass and soil organic matter, a process termed carbon sequestration. Carbon sequestration decreases with increasing mean annual precipitation in native rangelands of the North American Great Plains. The general trend for grazing was a decrease in carbon sequestration with longevity of the grazing management practice, whereas carbon sequestration increased with time since interseeding of a nitrogen-fixing legume, illustrating the importance of nitrogen in carbon sequestration. The arena of management-environmental interactions is largely unexplored at this time, but knowledge developed here will increase understanding of nutrient cycling through climate-plant-soil-microbial interactions.
Technical Abstract: Management of rangelands can aid in the mitigation of rising atmospheric CO2 concentrations via carbon storage in biomass and soil organic matter, a process termed carbon sequestration. Here we provide a review of current knowledge on the effects of land management practices (grazing, nitrogen inputs, and restoration) and precipitation on carbon sequestration in rangelands. Although there was no statistical relationship between change in soil carbon with longevity of the grazing management practice in native rangelands of the North American Great Plains, the general trend seems to suggest a decrease in carbon sequestration with longevity of the grazing management practice across stocking rates. The relationship of carbon sequestration to mean annual precipitation is negative for both the 0-10 cm (0-3.9 in) and 0-30 cm (0-11.8 in) soil depths across stocking rates. The threshold from positive to negative carbon change occurs at approximately 440 mm (17.3 in) of precipitation for the 0-10 cm soil depth and at 600 mm (23.6 in) for the 0-30 cm soil depth. We acknowledge that largely unexplored is the arena of management-environment interactions needed to increase our understanding of climate-plant-soil-microbial interactions as factors affecting nutrient cycling. Continued refinement of estimates of terrestrial carbon storage in rangelands will assist in the development of greenhouse gas emissions and carbon credit marketing policies, as well as potentially modifying government natural resource conservation programs to emphasize land management practices that increase carbon sequestration. [GRACEnet Publication]