عنوان مقاله [English]
Deficiency of irrigation water in irrigated agriculture as the most deterrent factor and nitrogen Deficiency of as one of the main limiting factors of plant growth, is Presented. So management of water and nitrogen fertilizer for agricultural production because of Deficiency of resources and environmental problems and prevent loss of capital, should be considered. The purpose of this study was to optimize the water use efficiency and nitrogen fertilizer using marginal analysis theory for silage maize in Pakdasht located in the southeastern region of Tehran. The tests in the summer of 1393 in the form of split plot randomized complete blocks design with four treatments for water and four treatments for nitrogen fertilizer in three replications was used. The results showed that the maximum water use efficiency at ET = 839 mm and fertilizer consumption 384 kg per hectare happens while the global maximum yield at ET = 1020 mm and fertilizer consumption 365 kg per hectare is achieved and by 17.74% of water saving only 9.73 percent of the product is reduced. So when we face with restriction of water sources, water use efficiency must be goal and if there are no restrictions for water supply, with the goal of maximizing yield the values optimal irrigation and fertilization be specified. As well as the water supply should not exceed from 1020 mm.