Soil-Profile Carbon Sequestration Under No-till Systems.

No-till technology is being promoted as an alternative to conventional till systems to restore soil organic carbon (SOC) and reduce net emissions of greenhouse gases. No-till benefits to soil and water conservation and reduction of production costs are well recognized, but the potential of no-till for sequestering SOC has not been critically examined. Some studies have indicated that no-till soils mainly accumulate SOC near the soil surface, and the total profile SOC between no-till and conventionally tilled soils management may not differ. Thus, a more objective assessment of the potential of no-till systems for SOC sequestration for the entire soil profile based on well-designed and long-term experiments is needed. Most previous studies have focused on the shallow surface soil (<30 cm depth) and not the whole profile. Therefore, we  determined SOC concentration in long-term (>20 yr) no-till systems as compared to conventionally till across representative soils and different precipitation gradients in Kansas. Our preliminary results show that no-till management reduced bulk density and increased SOC concentration near the surface layers as compared to conventionally tilled soils. More results and discussion about this regional study will be presented at the meetings.