Cotton Yield and Water Productivity Affected by Conservation Tillage and Irrigation Methods in Cotton-Wheat Rotation

In this study, the effect of conservation tillage and irrigation methods on the soil properties, cotton yield, and water productivity was evaluated in a wheat-cotton cropping system in the form of a split-plot experimental design. The main plots were irrigation using the three methods including surface irrigation, drip tape irrigation, and sprinkler irrigation. Tillage methods including zero tillage, reduced tillage, and conventional tillage were considered as subplots in this research. Results showed that tillage methods had no significant effect on cotton yield; whereas, the cotton yield was significantly affected by irrigation methods (p˂0.05). Tape and sprinkler irrigation methods saved water compared to surface irrigation for 51% and 28%, respectively. The maximum water productivity (0.324 kg m-3) was obtained from the tape irrigation and the minimum water productivity (0.146 kg m-3) was related to surface irrigation. Results also indicated that irrigation and tillage methods had a significant effect on the soil bulk density and infiltration rate so that drip tape irrigation and conventional tillage had the highest infiltration rates, and tape irrigation and reduced tillage had the highest soil bulk density.