Tillage and Compaction Effects On Greenhouse Gases Emission From Corn-Soybean-Oats Rotation in Ohio.

Green house gases produced by anthropogenic activities have been linked to the observed and predicted warming trends in global climate. Land management practices, soil properties and climatic factors are major regulators of greenhouse gases from farmland. The study was conducted to investigate the effects of compaction, tillage management and crop rotation on CO₂, N₂O and CH₄ emission on Crosby silt-loam soil in southern Ohio. Three levels of compaction 0, 10 and 20 tons were superimposed on no-till and conventional till management. Crop rotation was corn-soya bean-winter oat. Polyvinyl chloride chambers were installed (15 cm diameter) were installed in each plot in between plant rows. Vented chamber lids, fitted with sampling port were used to close the chambers during sampling and air samples were obtained at 0, 30 and 60 minute intervals and analyzed for CO₂, CH₄ and N₂O concentration by gas chromatography. Gaseous fluxes were measured at 2 to 4 weeks intervals for three years. In addition, soil moisture of the top 10 cm, and soil temperature at 5, 10 and 20 cm soil depth were determined for each sampling date. Significantly higher GHG fluxes were observed in spring (March-June) compared to other seasons of the year. The N₂O fluxes from corn were generally higher than from winter oats and soybean during growing period, probably due to N fertilizer application. Generally, annual CH₄ and N₂O fluxes increased with increase in compaction, but there were no discernable trends with compaction treatments for CO₂ fluxes.