Investigation of Water Productivity of Wheat in Some Irrigation and Drainage Networks of Khuzestan

Water productivity is one of the indexes which is widely used in the issues related to crop productivity and water, and is defined as the ratio of the amount of crop yield to the amount of water consumed by the crop. The water consumed by the crop may be supplied by rain, Irrigation or even irrigation plus precipitation. In fact water productivity is an indicator of the amount of production for each unit of consumed water. In this study, the amount of annual water productivity was indicated according to the available information and six years data-set, and then the mean value was reported for network’s crop water productivity. In this practice, ten networks namely, Avan, Dez, Shavoor, Maroon, Fajr & Jaizan, Gotvand, Karkhe, Ramshir and Shadegan were studied. Water productivity of the networks was estimated according t o the crop yield and the volume of consumed water. The highest rates belonged to Avan, Gotvand and Shadegan, being 1.03, 0.98 and 0.85 Kg.m-3 while Ramshir with an average water productivity of about 0.44 Kg. m-3 had the least value. An analyze over the relationship between crop yield and irrigation shows that, wheat crop yield will increase until the time that the crop’s water requirement is supplied, but it does not change or even decreases when the amount of applied water goes beyond the crop’s water requirement, thus as a result, the water productivity decreases.