Green House Gas Emissions Influenced by No-Tillage and Chisel Tillage Under Drainage and Non-Drainage Systems.

Subsurface drainage under poorly-drained soils can improve aggregation, aeration and water retention. Tillage under these poorly-drained soils influences mineralization of soil organic carbon (SOC) and in-turn alters the greenhouse gas (GHG) emisisons to the atmosphere. Subsurface drainage of no-till (NT) systems can remove excess water from the soil profile, improve aeration and reduce carbon dioxide (CO₂) and nitrous oxide (N₂O) fluxes. Therefore, the present field experiment was established at the Waterman Farm of The Ohio State University, Columbus, USA in 1994. Specific objectives of the study were to assess the effects of tillage and drainage systems on CO₂ and N₂O fluxes. The experimental layout was a factorial design comprising of two tillage and two drainage levels with three replications (12 plots). Specific treatments included: NT with drainage, NT without drainage, Chisel tillage (CT) with drainage, and CT without drainage. The GHG fluxes were monitored from all the 12 plots during 2011 and 2012 seasons using the static chamber-gas chromatography (GC) method. Results from this study show that subsurface drainage under NT plots had 9% higher SOC as than that under non-drainage NT plots. Based on the average of March 2011 through July 2012, the CO₂ flux monitored from soils of CT plots was 10-18% higher than those under NT. Similarly, the N₂O flux was also higher under CT plots. Subsurface drainage improved soil aeration, and reduced CO₂ and N₂O fluxes compared with those of non-drainage systems. Therefore, long-term NT with subsurface drainage system improves soil quality, and reduces GHG fluxes as compared to that of CT.