|Schuman, Gerald - ARS RETIRED|
Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: September 5, 2006
Publication Date: February 9, 2007
Citation: Derner, J.D., Schuman, G.E. 2007. Carbon sequestration and rangelands: Effects of length of management practice and precipitation gradients. Society for Range Management Meeting Abstracts. CDROM Traditions and Transitions #122. Technical Abstract: Management of rangelands can aid in the mitigation of rising atmospheric CO2 concentrations via carbon (C) storage in plant biomass and soil organic matter, a process termed C sequestration. Management practices that increase soil nitrogen (N), such as interseeding of N-fixing legumes, have the greatest potential to sequester C (0.33-1.56 Mg C·ha·yr-1) and illustrate the importance of N in C sequestration. In rangelands of the North American Great Plains, grazing is predicted to sequester C (0.07-0.30 Mg C·ha-1·yr-1 for semi-arid rangelands) for a period of time > 80 yr, but the sequestration rate decreases with time. In contrast to grazing, change in C with interseeding an N-fixing legume into rangeland is positive with time. Highly variable C sequestration rates (0.28-0.90 Mg C·ha-1·yr-1) occur on formerly cultivated lands. Soil organic C pools increase from semi-arid to mesic rangelands in the Great Plains, but C sequestration decreases with increasing mean annual precipitation above 440 mm for the 0-10 cm soil depth and above 660 mm for the 0-30 cm soil depth. Due to limited data, interseeding N-legumes did not show a response to mean annual precipitation, and highly variable findings negated any precipitation relationships for restored lands. Largely unexplored is the arena of management-environment interactions that are needed to increase our understanding of climate-plant-soil-microbial interactions as factors affecting nutrient cycling. Continued refinement of estimates of terrestrial C storage in rangelands will assist in the understanding of greenhouse gas emissions and aid in the development of C credit marketing policies, as well as potentially modifying government natural resource conservation programs to emphasize land management practices that increase C sequestration. [GraceNet related].