Impacts of Long-Term No-Tillage on Soil Organic Carbon and pH in the Northern Great Plains.

Adoption of no-till (NT) has increased steadily in portions of the northern Great Plains over the past 30 years. The conversion of clean-till (CT) and reduced-till (RT) to NT suggests a potential opportunity to sequester carbon and reduce the contribution from farming to the atmospheric CO₂ pool. Changes in fertilizer management following adoption of NT may impact soil chemical properties. Soil was collected in plots arranged in a randomized complete block where tillage treatments have been maintained since 1993. A mixed model with tillage and soil depth considered fixed effects and blocks considered a random effect was used to analyze soil for organic carbon content and pH. Tillage affected soil organic carbon, with 130 Mg ha^-1 under NT compared with 110 Mg ha^-1 under CT and RT (P < 0.05). An impact of tillage on soil pH was not detected. Results of this research indicate that conversion of CT and RT to NT can result in the sequestration of soil organic carbon in cool semiarid regions.