Effect of Strip Tillage on Corn Nitrogen Uptake and Residual Soil Nitrate Accumulation Compared with No-Tillage and Chisel Plow

摘要

Tillage and N management systems can have a significant effect on N use by corn (Zea mays L.) and nitrate (NO₃–N) movement through the soil profile. Potential water quality and NO₃–N loss problems associated with conventional tillage and fall-applied N have prompted this study. The objective is to evaluate strip tillage effect on corn N uptake and NO₃–N movement through the soil profile compared with chisel plow and no-tillage systems. The three tillage systems implemented in this study were strip tillage, no-tillage, and chisel plow along with two N application timings (fall and spring) of 170 kg N ha–1 for corn in a corn–soybean [Glycine max (L.) Merr.] rotation on two Iowa fields in 2001 and 2002. The three tillage systems were implemented every year for both crops (corn and soybean). Crop response, N uptake, and other soil NO₃–N measurements were conducted on a randomized complete block design experiment. Grain yields and grain N uptake showed no significant improvement under strip tillage compared with no-tillage or chisel plow systems. Tillage and N treatments caused no significant differences in NO₃–N accumulation at the lower depths of the root zone (1.2 m). Strip tillage and no-tillage resulted in lower residual soil NO₃–N buildup than chisel plow in the 0- to 1.2-m soil profile after 2 yr of tillage implementation. Tillage and N treatments did not cause significant differences in NO₃–N concentration in water leachate collected at the 1.2-m depth.