تحليل اقتصادي كم آبياري گندم در شرايط كرج

An Economic Evaluation of Deficit - Irrigation on Wheat Yield in Karaj

Water is indispensable in agriculture. Water shortage, along with low irrigation efficiencies in Iran, a Semi-arid country, necessitates research in deficit irrigation. The present research was carried out on winter wheat, Ghods variety, at the experimental farm, of Agriculture, University of Tehran. The aim was to determine the production function and study the economic effects of deficit irrigation upon yield. Irrigation interval for low, medium and high stress treatments were 7, 14 and 21 days respectively. Penman Monteith method was used to find out the crop water requirements. Water applied to different treatments as a percentage of control, namely full or 100% irrigation, was as follows: 70, 80 and 90 percent for low, 40, 50, 60 for medium and 10, 20, 30 for high stress treatments the treatments of 110 and 0 percent of required water were employed to evaluate the effects of over irrigation and no irrigation (dry/land). The production, income, cost and profit functions have shown that the highest grain yield was 5900 Kglha corresponding to 400 mm water depth. The maximum income (2750000 Rialslha) belonged to complete irrigation (405mm) in the case of land limitation. Maximum benefit was obtained with reduction of in required water by 20%. The benefit obtained from treatment with 40% reduction in required water was equal to benefit of complete irrigation. In the case of water shortage, the maximum profit was obtained with 65% reduction in required water along with increasing production area three folds.