Optimizing water consumption of sugar beet in conditions of the irrigation water salinity and dependency of the yield price to quality

Scarcity of irrigation water and reduction of its quality are the most important reasons in reducing the growth and yield of agricultural products in arid and semi-arid regions. Optimization of the water use and proper management of saline water is a way to increase water use efficiency. In this research, sugar beet production function was obtained based on the amount and salinity of irrigation water. Then, the needed equations for determining the optimum irrigation water depth when the price of sugar beet is variable and dependant on its quality (sugar content rate) is determined. For salinity of 0 ds/m and based on current prices of water and crop, optimum amounts of water were 1.87, 1.77 and 1.52 m to obtain the maximum yield and maximum profit under limited land and limited water conditions, respectively. The amount of water saving under water limiting conditions were 18.7 %, respectively, and the cultivation area increased by 20%, respectively.