Effect of deficit irrigation on quantitative properties of winter wheat and determination of its optimum applied water in Shahrekord

For investigation of effect of deficit irrigation on quantitative properties of winter wheat, a completely randomized design consisted of 36 plots( 9 irrigation treatments and 4 replications) was conducted at farm research(with sandy loam texture) of Shahrekord university in 1384-1385. The irrigation treatments were applied since the first of Khordad ,1385, because before the date irrigation requirement was zero in Shahrekord climate. The irrigation time was determined base on which time 50% depletion of soil water content in full irrigation treatment occured. T1 and T2 treatments were over irrigation, T3 was full irrigiation and other treatments were under different levels of  deficit irrigation. The results showed that the deficit  irrigation effect on quantitative properties of winter wheat (consists total, grain and straw yield and wheight of thousand grain) significantly, so that depth of apply water which maximize grain yield per hectar  was 314mm. Finally the depth of applied water  for irrigation of  winter wheat that maximizes net income was 106 mm. While according to crop production  function the depth of applied water that maximizes grain yield was 314 mm. Thus in the water limiting situation the optimum depth of applied water is equal to 34% of full irrigation. Thus, using deficit irrigation, irrigated area can be increased 2.9 time related to full irrigation.