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

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Abstract
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.