Assessing the Wheat Yield under Irrigated and Rainfed Farming and Evaluating the Possibility of Supplemental Irrigation of Rainfed by Water Stored in Deficit Irrigated Farming

This experiment was conducted as a randomized complete block design at Research Field of Agriculture Faculty of Tabriz University in 2015-2016 growing season. yield and yield components of irrigated wheat under three stress levels (full irrigation, 30% stress and 50% stress) and rainfed wheat under three supplemental irrigation levels (without irrigation, one-time irrigation at June and two-time at May and June) were evaluated with three replicated. Results showed that water stress reduced 1000-grain weight, number of seeds in spike and consequently, decreased grain yield. In rainfed farming wheat, the treatments with two supplemental irrigations had the largest number of seeds in the spike and, the maximum straw yield. In the rainfed wheat yield there was not observed a significant difference between the treatments that were irrigated once (at June) and the treatments that were irrigated twice (during May and June). Although 30 percent of water stress applied to reduce irrigated wheat yield as 1.13 ton/ha, but using 64.1 percent of stored water resulting from this stress, as a supplemental irrigation at June, increased yield of rainfed wheat farming as 2.16 ton/ha. This matter will be increased yield production and wheat water use efficiency.