Submitted to: USDA-ARS Research Notes
Publication Type: Other
Publication Acceptance Date: 10/6/2010
Publication Date: 10/6/2010
Citation: Franzluebbers, A.J. 2010. Soil-Profile Organic Carbon and Nitrogen during 12 Years of Pasture Management. JPC Research Note 17. 2009.
Technical Abstract: Carbon dioxide (CO2) in the atmosphere has been increasing steadily during the past century. This is well documented by measurements in Hawaii since 1958 (initiated by Dr. Charles Keeling). Increasing CO2 in the atmosphere is a concern, because of its potential to warm the planet. CO2 and other greenhouse gases act as a barrier to prevent heat escaping from the atmosphere. Sequestration of soil organic carbon (C) and conservation of soil nitrogen (N) are of keen current interest to scientists, policy makers, agri-businesses, and landowners as a means of mitigating three important greenhouse gases [i.e. CO2, methane (CH4), and nitrous oxide (N2O)]. In the warm, humid region of the southeastern USA, pastures are recognized as an important land use capable of storing a large quantity of soil organic C and N. Although documentation is available for significant soil organic C sequestration in surface soil, very little research has been conducted on soil-profile (0-5’) sequestration. Farmers, scientists, and environmental specialists can benefit from this information to guide more effective sampling strategies and to acquire better estimates of soil organic C sequestration with cattle grazing systems. Assuming that the 34 million acres of pastureland in the southeastern USA were to sequester 0.46 Mg C/ha/yr (0.68 metric tons CO2 equivalence per acre per year) to a 4-foot depth as observed in this study, a total of 6.3 Tg of C (23 million metric tons of CO2) could potentially be stored each year as a result of grass management in the region, a value of similar magnitude to that potentially stored if all cropland in the region were converted to no-tillage.