The 2008 Joint Meeting of the Society for Range Management and the America Forage and Grassland Council.

Tuesday, January 29, 2008 - 4:40 PM

Soil Organic Carbon Sequestration in Pastures

Alan J. Franzluebbers, USDA-ARS, 1420 Experiment Station Road, Watkinsville, GA 30677

Grazing lands in the eastern USA are managed primarily for introduced plant species that have high forage production potential or that fit a niche within a farming system. Forages are typically managed with fertilization and grazing pressure on a seasonal basis, depending upon growth habit. Abundant precipitation in the eastern USA compared with western rangeland allows for greater utilization potential of pastureland. Nitrogen application is one of the key determinants of pasture productivity, although its effect on soil C storage may be minimal, especially considering the C cost of fertilization. Fertilization with animal manures is effective and may provide additional C storage potential, although C may simply be transferred from one ecosystem to another. Moderate grazing of pastures may be the most effective strategy at storing soil C in pastures. Return of dung to the soil surface has positive effects on soil surface properties, including soil microbial biomass and total C. Grazing land managed with a moderate grazing pressure, i.e. utilizing forage to an optimum level without compromising regrowth potential, can provide economic opportunities for landowners with low risk, can improve degraded land by building soil fertility, can improve water utilization and quality within the landscape, and can help mitigate the greenhouse effect by storing C in soil as organic matter.