Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/25/2004
Publication Date: 10/31/2004
Citation: Stahl, P.D., Schuman, G.E., Ingram, L.J., Buyer, J.S., Ganjegunte, G.K., Vance, G.F., Welker, J.M. 2004. Influence of grazing treatments on soil microbial community structure in a northern mixed grass prairie [abstract]. American Society of Agronomy Annual Meeting Abstracts [CDROM]. No. 4140. Interpretive Summary:
Technical Abstract: Rangelands in the western United States appear to have great potential for additional storage of carbon in the soil. A number of studies indicate well managed grazing, under certain environmental conditions, may increase carbon storage in soil but little is known regarding the mechanisms involved and impacts of grazing on soil organisms. Therefore, we assessed microbial community structure using phospholipids fatty acids (PLFAs) as one method of examining soil organic carbon (SOC) dynamics on grazed rangelands and ungrazed exclosures 20 years after initiation of grazing. Grazing increased SOC in the 0-30 cm depth after 10 years of grazing, but, after 20 years, including several years of severe drought, there was little difference between ungrazed and lightly grazed treatments and the heavily grazed treatment exhibited a significant loss of SOC. Multiple analysis of variance using biomarker PLFAs indicated a significant grazing treatment effect at both depths examined, 0-5 cm and 5-15 cm. Results show that soil microbial community structure in the lightly grazed treatment is distinct from that in the heavily grazed treatment and the ungrazed treatment is intermediate.