Submitted to: Advances in Soil Science
Publication Type: Book / chapter
Publication Acceptance Date: 9/6/2000
Publication Date: 9/15/2000
Citation: Schnabel, R.R., Franzluebbers, A.J., Stout, W.L., Sanderson, M.A., Stuedemann, J.A. 2000. The Effects of Pasture Management Practices. In: Follett, R.F., Kimble, J. M., Lal, R. The potential of U.S. grazzing lands to sequester carbon and mitigate the greenhouse effect. Boca Raton, FL: Lewis Publishers. P. 291-317. Interpretive Summary: The past conversion of forests and grasslands to arable lands in developed countries, the continued loss of forests in developing countries and the burning of fossil fuels around the world has resulted in rapidly elevating atmospheric CO2 concentrations. The search is on for ways to slow this trend. Just as past changes in land management released carbon stored in the soil into the atmosphere, changing land management practices now can increase the amount of carbon stored in the soil. Managing the existing 53 million hectares of pastures in the eastern U.S. to increase soil organic carbon and converting marginal cropland to grassland are two major options for the agricultural sector to mitigate atmospheric CO2 concentrations. While too little information exists to precisely predict where, by what amount, and for how long management changes will increase soil organic carbon, we do know what works. Managing grasslands so grazing animals more fully utilize pasture plants, increasing the productivity of pastures and changing the type of grasses growing in pastures have all been shown to increase soil organic carbon. A cautionary note, if pastures are managed solely to increase soil carbon it could have an adverse affect on nonpoint source water pollution.
Technical Abstract: The 53 million hectares of pastureland in the U.S. are among the most productive in the world. These grassland soils store a large quantity of organic carbon. Managing existing pastures to increase soil organic carbon and converting marginal cropland to grassland are two major options for the agricultural sector to mitigate atmospheric CO2 concentrations. Various approaches to managing the animals, forages and soils of pastures have bee shown to increase soil organic carbon. Stocking pastures to more fully utilize pasture grasses, and improving the fertility of pasture soils increase both soil organic carbon and animal productivity. Growing gasses that are more productivity but decompose more slowly is another way to increase soil organic carbon. Increases in soil organic carbon are most likely to occur on soils with low to moderate fertility. Management to increase SOC may reduce atmospheric CO2 concentrations but increasing soil fertility could have the unintended consequence of increasing nonpoint source pollution, and may also adversely impact farm prices.