Submitted to: Soil Science Society of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 11/5/2007
Publication Date: 11/5/2007
Citation: Schuman, G.E., Vance, G.F., Derner, J.D., Ingram, L.L., Stahl, P.D. 2007. Long-term effects of grazing and precipitation on carbon sequestration and microbial dynamics on rangelands. Proceedings: ASA, CSSA, SSSA Annual Mtng. November 2007, New Orleans, LA. CDROM. Interpretive Summary:
Technical Abstract: Grazing at light to heavy stocking rates in northern mixed-grass rangeland increased C sequestration after 12 years (1982-1993); however, drought conditions 7 of the following 10 years (1993-2003) resulted in a 30% loss of the sequestered C where grazing was heavy with concurrent shifts in the plant community from cool-season to warm-season perennial grasses. Nitrogen mineralization, microbial biomass and microbial respiration were greater with light or no grazing compared to heavy grazing in 2003. In addition, phospholipids fatty acid analysis indicated soil microbial community structure was influenced by grazing. Amounts of annual precipitation were average or above from 2003-2005 with soil sampling conducted in early spring 2006 to assess short-term responses of C sequestration following these 3 years of average or better precipitation following drought. Grazing management can increase C sequestration in this rangeland ecosystem, but the dynamics of C sequestration are also dependent on precipitation amount and distribution.