عنوان مقاله [English]
The most important factor limiting agricultural products in arid and semi-arid region is water scarcity. Increasing the water use efficiency is one of the agricultural development solutions. The purpose of this study is to optimize water use efficiency using Elasticity Index for silage maize in Qazvin region. The data of this study were collected from the results of Sotoodehnia (2002) that was conducted on 704 single crass varieties in Ismail Abad in Qazvin during two years of field research in 1379 and 1380. Data included, crop yield and seasonal evapotranspiration of full and deficit irrigation treatments, that by using this data, production function, water use efficiency and elasticity of water productivity were determined. Using these functions were shown, the maximum water use efficiency of 3.58 kilogram per hectare with 508 millimeter evapotranspiration and yield of 18178 kilogram per hectare achieved. Also, to achieve maximum yield (21330 kilogram per hectare), evapotranspiration of 683 millimeter (25.6 percent more than maximum water use efficiency) is required.