Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/19/2004
Publication Date: 10/31/2004
Citation: Ganjegunte, G.K., Vance, G.F., Preston, C.M., Schuman, G.E., Ingram, L.J., Stahl, P.D., Welker, J.M. 2004. Characteristics of soc constituents under different grazing management practices in a northern mixed-grass prairie. Agronomy Abstracts 4283. Interpretive Summary:
Technical Abstract: The northern mixed-grass prairies are an extensive component of the Great Plains of the U.S. and are used extensively for grazing. Research has shown that different grazing management practices and environmental conditions can influence the amount of soil organic carbon (SOC) in these ecosystems. We conducted a study at the High Plains Grasslands Research Station near Cheyenne, WY to evaluate SOC in light (LG) and heavy (HG) grazed sites and in 60 year old exclosures (EX). Soils (0-5 cm) from each treatment were analyzed for total C and N contents and lignin composition using CuO oxidation. Total soil C and N were not significantly different, but significantly higher lignin contents were noted in EX vs HG soils. Soil humic (HA) and fulvic (FA) acids analyzed by 13C NMR, 13C and 15N stable isotopes and CuO oxidation indicated HA had greater alkyl and methoxyl C and FA had greater O-alky C, suggesting more recalcitrant C compounds in HA. However, the HA from LG soils had significantly greater total N and di-O-alkyl C and lower phenolic C compared to HG soils. This would suggest SOC quality was influenced by grazing management, and the LG results in more readily decomposable SOC.