Effect of different tillage methods and the rate of crop residues on yield, yield components and economic efficiency of wheat

To investigatr the effect of different tillage methods and crop residues on yield, yield components and economic efficiency of wheat, an experiment was carried out as split-plot layout based on randomized complete block design with three replications at research station of Gonabad during 2012-13 growing season. Three tillage methods including conventional tillage (CT), reduced tillage (RT) and no tillage (NT) were allocated to main plots and three crop residues containing without residue (R0), 30% (R1) and 60% (R2) of residues retention were assigned in sub plots. Results showed that different tillage methods and rate of residue management had not significantly effects on dry matter accumulation in different developmental stages, biological yield, grain yield and harvest index. Tillage methods had only significantly effect on number of spike per m2. The highest level of biological yield was obtained from RT treatment. With increasing crop residues from zero to 60%, biological and grain yield were increased, so that the highest amount of biological yield was obtained from retention of 60% residues. The highest level of grain yield was related to CT R2 treatment. However, CT R1 and RT R2 treatments were the best treatments in view point of economic and had the highest rate of net income and rate of return.