Assessment of Five Soils in Western Oklahoma to Mitigate Rising Greenhouse Gas Concentrations.

The increasing global atmospheric concentration of CO₂ has resulted in national and international concern about the impact of global warming.  One possible way to reduce global atmospheric CO₂ concentration is to move atmospheric CO₂ into the soil profile.  Soil organic carbon (SOC) decreases with initial tillage.  After continued tillage, the soil will eventually reach a new equilibrium.  By manipulating management strategies, primarily conversion from conventional tillage into a no till systems, it is possible to increase the SOC content.  Therefore, this study evaluated the potential of soil to sequester carbon and the rate at which sequestration could occur.  Five sites were selected in western Oklahoma, with three treatment zones located within the same soil series.  The treatment zones consisted of native grassland that had not experienced tillage, conventional tillage, and an area that had been placed into a no till system or grassland eliminating further tillage of the soil.  The no till treatment zones varied in length of establishment from 4 to 49 years.  The treatment structure allowed for a determination of maximum carbon storage potential in the native grassland, an assessment of current carbon content in the agricultural lands, and an evaluation of how management changes affect the soil organic carbon pool.  This study found that no till systems add carbon to the upper surface of the soil, and the rate of carbon sequestration varied from 50-320 kg C ha^-1 yr^-1.