Water is one of the scarcest factors of production in agriculture. There is a direct relationship between the development of the agriculture sector and the quantity and quality of the water resources and how to manage and use of these resources. Many efforts take place to reduce water use in agriculture and improvement of its allocation. The main purpose of this study is analysing the effect of change in water costs and reduction of available water on the cropping patterns of different products. For this purpose,changes in the cropping pattern of five products - wheat, barley, sugar beet, canola and tomato - in KhorasanRazavi province of Iran were studied using the positive planning in the six scenarios. The data of this study has obtained in the cities of Mashhad, Nishabur and Torbat-e- Heydarieh (in KhorasanRazavi province) for the crop year of 2011. The results show that the usage of water for wheat, barley and tomato in Mashhad and wheat, barley and sugar beet in Torbat-e-Heydarieh doesn’t change so much by increasing water price.
