Long-term tillage and drainage influences on greenhouse gas fluxes from a poorly drained soil of central Ohio

Intensive tillage practices and poorly drained soils of the Midwestern United States are one of the prime reasons for increased greenhouse gas (GHG) fluxes from agriculture. The naturally poorly drained soils prevalent in this region require subsurface drainage for improving aeration and reducing GHG fluxes from soils. However, very little research has been conducted on the combination of tillage and drainage impacts on GHG fluxes from poorly drained soils. Thus, the present study was conducted in central Ohio with specific objective to assess the influences of long-term (18-year) no-tillage (NT) and chisel-till (CT) impacts on carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) fluxes from the soils in plots managed under drained (D) or nondrained (ND) conditions. The experimental site was established on a poorly drained Crosby silt loam soil in 1994 under corn (Zea mays L.)-corn rotation. Measurements of soil CO2, N2O, and CH4 fluxes were conducted biweekly during 2011 and 2012 using the static chamber technique. In 2011, the annual CO2-C and N2O-N from NT were 18% and 83%, respectively, lower compared to CT. Similar trends were observed for 2012. Methane fluxes were highly variable in both years. Tillage and drainage influenced seasonal soil GHG emissions; however, differences were not always significant. In general, plots under NT with subsurface drainage produced lower emissions compared to those under CT. Subsurface drainage lowered the emissions compared to those under ND. Results from this study concluded that subsurface drainage in poorly drained soils with long-term NT practice can be beneficial for the environment by emitting lower GHG fluxes compared to tilled soils with no drainage. However, long-term monitoring of these fluxes under diverse cropping systems under poorly drained soils is needed.