Optimizing Consumptive Water depth for Corn by Deficit-Irrigation (Case Study: Varamin area)

Deficit – irrigation is an optimum approach of water application under water deficit or expense. In this research, the effect of deficit-irrigation has been investigated for corn plant (variety of single cross 704). The experiment carried out in case of randomized complete block design which has 13 treatments and 3 repeats. The first treatment was without any irrigation and next treatments have increase of 10 % of full water requirement respect to previous one up to 120%. The results showed full irrigation (82.4 cm application water depth in unit area) had maximum yield of 77360 kg/ha, and dry-farming and deficit-irrigation by application water depth of up to 30% of water requirement had only loose of money for farmer. Furthermore, Maximum pure benefit was related to treatment with 10% decrease in full irrigation. The highest value for gross and pure income belonged to treatments by 50% and by 30% decreases in requirement water depth respectively. In general, results showed irrigation by application depth more than requirement depth not only decreased the benefits but also the yields. In case of limitation in water resources and permission to increase area of farming, the highest value in pure benefit will obtain in treatment by full irrigation.