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 Midwestern USA are the prime reasons for greenhouse gas (GHG) fluxes from agriculture. The naturally poorly-drained soils prevalent in this region require subsurface drainage for improved aeration and improved crop productivity. Soil surface GHG fluxes are strongly influenced by land management practices including tillage and drainage. However, little research has been conducted that can assess the combination of tillage and drainage impacts on soil GHG fluxes from poorly-drained soils. Thus, the present study was conducted on a poorly-drained soil of central Ohio with specific objective to: (i) assess the influences of long-term (19 yr) no-tillage (NT) and chisel till (CT) impacts on carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) fluxes from the soil in plots managed under drained (D) or non-drained (ND) conditions. The experimental site was established in 1994 under corn (Zea mays L.)-corn rotation on a Crosby silt loam soil. Measurements of soil CO2, N2O and CH4 fluxes were conducted bi-weekly during 2011 and 2012 using the static chamber technique. The data show that the annual CO2-C flux from NT was 28% lower compared to that under CT. Similarly, the N2O-N (1.17 vs. 3.61 kg ha-1) and CH4-C (1.73 vs. 1.81 kg ha-118) fluxes were also lower under NT vs. CT system. Further, tile-drained plots had lower soil CO2, N2O and CH4 fluxes as compared to plots without drainage (ND). Tillage and drainage both influenced seasonal soil GHG emissions; however, these changes were not always significant. In general, plots under NT and with a subsurface drainage system produced lower emissions compared to those under CT. Subsurface drainage lowered the emissions compared to emissions under ND. Results from this study concluded that subsurface 1 drainage of poorly-drained soil with long-term NT practice can also be beneficial for the environment by emitting lower GHG fluxes compared to tilled soil with no drainage system. However, long-term monitoring of these fluxes under diverse cropping systems under poorly drained soils is needed.