Effect of conservation tillage and irrigation methods on the cotton yield and water use efficiency

In this study, the effect of conservation tillage and irrigation methods on the crop yield and water use efficiency was evaluated in cotton. The research was conducted in the form of a split plot experimental design with three replications in Darad area of Fars province in 2010. The main plots were irrigation methods including surface irrigation (gated pipe), tape irrigation, and sprinkle irrigation. Tillage methods including zero tillage (direct drilling), reduced tillage, and conventional tillage (control treatment) were considered as sub plots in this research. Treatments were applied in plots with dimensions of 20 by 6 m and a local cotton cultivar (‘Bakhtegan’) was planted in the plots. Soil moisture content, soil bulk density, cotton water consumption, cotton yield, and water use efficiency were measured in different tillage and irrigation treatments. Collected data were analyzed using SAS software and Duncan’s multiple range tests were used to compare the treatment means. Results showed that the maximum water consumption (16320 m3) occurred in the surface irrigation (gated pipe) whereas the minimum water consumption (8139 m3) was related to the tape irrigation. Conservation tillage methods had a significant effect on the cotton yield and water use efficiency so that the reduced tillage treatment had the highest cotton yield and water use efficiency while the conventional tillage had the lowest cotton yield and water use efficiency. Cotton yield and water use efficiency were also significantly affected by irrigation methods in such a way that the maximum cotton yield was obtained from the sprinkle irrigation method whereas tape irrigation had the maximum water use efficiency. The minimum cotton yield and water use efficiency were also related to the surface irrigation method.