Effect of Tillage, Wheat (Triticum aestivum L.) Residue & Nitrogen Management on Corn (Zea mays) Yield and Yield Components

Conservation tillage practices integrated with appropriate residue management is an efficient approach in sustainable agriculture to prevent the removal or burning of crop residues. Two years field experiments were conducted to evaluate the effect of wheat residue management on yield, yield component and morphophysiological characteristics of corn. Experimental design was split plot using three factors. Main factor was three tillage systems including moldboard plow, once and two times chisel plow; and sub factors were four wheat residues (0, 25, 50 and 75%) and three nitrogen levels (69, 103.5 and 138 kg/ha). With increase in residue levels and decrease in tillage and nitrogen levels, grain and biological yields and grain number per ear decreased, but thousand grains weight was not significantly different among treatments. Although tillage had no significant effect on leaf area index, increase in residue and decrease in nitrogen levels, decreased corn leaf area index. Since there was no significant difference between two times chisel plow with 25% wheat residue + 103.5 kg N/ha, and moldboard plow with 0% wheat residue + 138 kg N/ha treatments, maintenance of 25% wheat residues, and application of a lower nitrogen rate (103.5 kg N/ha) is recommended in order to achieve sustainability in corn fields.