Effect of Deficit Irrigation on Yield, Yield Components, and Water Use Efficiency of Corn under Drip Irrigation

     Deficit (or regulated deficit) irrigation is one way to improve efficiency of water use when crop is exposed to a certain level of water stress during a particular growth period. In order to optimizing water use under tape irrigation system, a field experiment was carried out during 2010 growing season at the experimental farm of Agriculture and Natural Resources Research Center of Orzoueyeh, located in Kerman province. The treatments were laid out in completely randomized block design with three replications., Four water potential thresholds for starting the irrigation treatments were selected by using tensiometers (net water requirement (control) and suctions of 1/2 FC, 1/5 FC and 1/8FC). The crop studied was corn, single cross 704 cultivar. The results showed that water use volumes saved in the three suction treatments consisting of treatments 1/2 FC, 1/5 FC and 1/8FC were 11%, 13% and 17 percent, respectively, in comparison with the control treatment. But, compared to the control, yield of the mentioned treatments decreased by 4 %, 28%, and 34 percent, respectively. However, water use efficiency increased in the 1/2 FC treatment by 6.5% over the control treatment. Statistical analysis of yield components in the control and 1/2 FC treatments demonstrated that these two treatments were in the same group. Among the evaluated treatments, the control and 1/2 FC treatments were economically satisfactory.