determining the optimum cropping pattern in same direction with water resources management of mashhad-chenaran plain

abstract in refrence to un appropriate time and place dispersal of precipitation in iran and having low efficiency in agriculture, water as the most limitative factor in agriculture is discussing. in this study, the existing pattern of mashhad-chenaran plain is considering and with gathering data related to 1388, with target of decrease in water consuming, optimum and nearly optimum cropping pattern was determined. in order to reach to this target, we used linear programming and modeling to generate alternatives. related result which were reached from linear programming showed that use of all under cropping area and also reaching gross margin like existing pattern, the amount of water consuming had been decreased which is resulted from new compound of yields in production system. also in the optimal state surface of products such as sugar beet, beans and sunflower due to high water consumption and having lower gross margin were removed from the cropping pattern. also nearly optimum pattern showed that even an increase of 5% and 7% in amount of consuming water rather than optimum position, only at most 1.5% gross margin had been increased, that because of importance using continuous of water resource and protection of this worthful resource, so extra utilization doesn’t recommend. in refrence to result, using making optimum patterns in codifying cropping pattern in plain are recommended.