Assessment of Water-Salinity Production Functions of Forage Maize in Khorasan Razavi Province

The great challenge of the agricultural sector in countries located in arid and semiarid regions in the face of inadequate quantity and quality of water, Produce more food with less water or agricultural production is optimized. Such methods can be used to optimize agricultural production, water-salinity production functions named that Planning and policy for agricultural production in this area is useful. To determine the crop water production function water-salinity, this experiment was carried out at 2011 in Khorasan Razavi provience. Maize was grown with three levels of saline water (1.8, 3 and 4.6 dS/m), four levels of applied water (100, 75, 50 and 25 percent of water requirement) and four levels of stage of deficit irrigation applied (continuously during the growing season, vegetative, flowering and grain filling). Data were analyzed using linear, quadratic, Cobb-Douglas and transcendental functions. Results showed that quadratic function estimated yield better under salinity and water stress. Marginal rate of technical substitution showed that water salinity and water supply can be substituted with the other in a wide range in order to achieve equal amount of yield. Marginal production of water quantity and quality were 0.77 and -2.75 ton.ha-1, respectively.