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United States Department of Agriculture

Agricultural Research Service

Title: Particulate and Non-Particulate Fractions of Soil Organic Carbon under Pastures in the Southern Piedmont Usa

Authors
item Franzluebbers, Alan
item Stuedemann, John

Submitted to: Environmental Pollution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 20, 2001
Publication Date: March 1, 2002
Citation: Franzluebbers, A.J., Stuedemann, J.A. 2002. Particulate and non-particulate fractions of soil organic carbon under pastures in the Southern Piedmont USA. Environmental Pollution.

Interpretive Summary: Pasture management could be effective at sequestering soil organic carbon, which could help mitigate the rising concentration of carbon dioxide in the atmosphere. Increasing soil organic carbon benefits farmers also, by improving fertility and buffering soil from nutrient and sediment losses. In soils of the Southern Piedmont USA, storage of soil organic carbon was (i) greater under pasture than under conservation-tillage cropland, (ii) greater when pasture was grazed than when hayed, (iii) marginally greater with higher fertilization of pasture, (iv) greater with higher frequency of endophyte infection of tall fescue, and (v) greater under increasing stand age of grass. Managing soil carbon as an environmental commodity should include considerations of pasture management in the southeastern USA.

Technical Abstract: Pasture management can be effective at sequestering soil organic C. We determined the depth distribution of particulate organic C (POC), non-particulate organic C (NPOC), particulate-to-total organic C (POC-to-TOC) ratio, and particulate organic C-to-N (POC-to-N) ratio under pastures near Watkinsville, Georgia, USA. Particulate organic C was highly yrelated with TOC, but became an increasingly larger portion of TOC near th soil surface, where both pools were greatest. Particulate and NPOC were (i) greater under pasture than under conservation-tillage cropland, (ii) greater when pasture was grazed than when hayed, (iii) marginally greater with higher fertilization of pasture, (iv) greater with higher frequency of endophyte infection of tall fescue, and (v) greater under increasing stand age of grass. Soil under pasture comparisons that had greater TOC content had (i) larger improvements in POC than in NPOC and (ii) lower POC-to-N ratios, suggesting improvement in biochemical soil quality, as well as soil C sequestration.

Last Modified: 4/20/2014
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