z-logo
Premium
Grazing Impacts on Soil Carbon and Microbial Communities in a Mixed‐Grass Ecosystem
Author(s) -
Ingram L. J.,
Stahl P. D.,
Schuman G. E.,
Buyer J. S.,
Vance G. F.,
Ganjegunte G. K.,
Welker J. M.,
Derner J. D.
Publication year - 2008
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2007.0038
Subject(s) - grazing , environmental science , soil carbon , agronomy , ecosystem , rangeland , soil respiration , growing season , mineralization (soil science) , biomass (ecology) , plant community , microbial population biology , zoology , soil water , ecology , biology , agroforestry , species richness , soil science , genetics , bacteria
Good management of rangelands promotes C sequestration and reduces the likelihood of these ecosystems becoming net sources of CO 2 As part of an ongoing study, soil was sampled in 2003 to investigate the long‐term effects of different livestock grazing treatments on soil organic carbon (SOC), total nitrogen (TN), and microbial communities. The three treatments studied (no grazing, EX; continuously, lightly grazed [10% utilization], CL; and continuously, heavily grazed [50% utilization], CH) have been imposed on a northern mixed‐grass prairie near Cheyenne, WY, for 21 yr. In the 10 yr since treatments were last sampled in 1993, the study area has been subject to several years of drought. In the 0 to 60 cm depth there was little change in SOC in the EX or CL treatments between 1993 and 2003, whereas there was a 30% loss of SOC in the CH treatment. This loss is attributed to plant community changes (from a cool‐season [C 3 ] to a warm‐season [C 4 ] plant dominated community) resulting in organic C accumulating nearer the soil surface, making it more vulnerable to loss. Soil TN increased in the EX and CL treatments between 1993 and 2003, but declined in the CH treatment. Differences in plant community composition and subsequent changes in SOC and TN may have contributed to microbial biomass, respiration, and N‐mineralization rates generally being greatest in CL and least in the CH treatment. Although no significant differences were observed in any specific microbial group based on concentrations of phospholipid fatty acid (PLFA) biomarkers, multivariate analysis of PLFA data revealed that microbial community structure differed among treatments. The CH grazing rate during a drought period altered plant community and microbial composition which subsequently impacted biogeochemical C and N cycles.

This content is not available in your region!

Continue researching here.

Having issues? You can contact us here