Effect of Crop Rotation and Wheat Residue Management on Grain Yield of Maize cv. KSC704 and Some Soil Properties

To study the effect of crop rotation and wheat residues management on grain yield, some agronomic characteristics of maize, and some properties of soil in second cropping system, an experiment was carried out in Experimental Research Farm of Orzoiyeh in Kerman Province for four cropping seasons (2000-2003). A split plot arrangement in a randomized complete block design was used with four replications. Wheat residue management at four levels (retention residue, burning and retention of residue every other year, removing residue, burned residue) were assigned to main plots, and crop rotation with three levels (1- wheat- cotton, wheat- corn, 2- wheat- soybean, wheat- corn, 3- wheat- corn, wheat- corn) were randomized in sub-plots. Results showed that yield and yield components, kernel protein content, organic carbon, available phosphorus, and bulk density in soil were not affected by wheat residue management, but available potassium in soil was affected significantly. Grain yield in residue retention treatment was 1150 kg ha-1 higher than burning residue. Organic carbon in retention and burning residue treatments were %0.65 and %0.59, respectively. Burning wheat residue increased available Potassium (204.95 mg/kg) in soil when compared with residue retention (180.04 mg/kg) and removing residue (178.48 mg/kg) treatments. Yield and yield components were not affected by crop rotation, but cotton in rotation had the highest potassium, phosphorus and organic carbon in soil. Based on these results and considering low organic carbon in soil and high temperature in summer in Orzoiyeh region, retention of wheat residue and rotation of cotton and maize after harvesting wheat are recommended. It is also suggested that the effect of wheat residue and crop rotation on grain yield and soil properties should be studied for a period of at least ten years .