Carbon Emissions From Two Long-Term Tillage and Crop Rotation Experimental Sites.

As the worry about C emissions continues to grow, the need for better understanding of where these emissions come from is needed. How much C is emitted in the course of one agricultural growing season and whether different crop rotations or tillage regimes provide fewer emissions can all inform which practices should be recommended. We looked at two continuously maintained sites (Wooster 50 years and Hoytville 48 years) under plow tillage (PT), chisel tillage (MT), or no-tillage (NT) in crop rotations of either corn after corn (CC) or corn after soybean (CS) to determine C emissions from each. Taken into consideration were fertilizer applications, chemical applications, and farm operations such as tillage and planting. In the first 10 years NT showed the highest emissions due to weed control under NT requiring highest rates of pesticides. However, over the total 50 years NT has shown the fewest total emissions of all tillages. For crop rotation, C emissions over the total 50 years of this study showed CS being slightly less than CC. Overall the interaction between tillage and rotation is important to lowering C emissions, however NT with a two-year rotation of corn and soybean would appear to yield the lowest emissions overtime.