WATER PRODUCTIVITY OF RICE PRODUCTION IN NORTHERN IRAN UNDER WATER DEFICIT CONDITION: FIELD AND MODELING APPROACH

Freshwater availability for irrigation decreases because of increasing demand from urban and industrial areas, degrading irrigation infrastructure, and water quality. The demanding for high production of rice with less water use is crucial for food supply. In this research, a field experiment was conducted during 2009 and 2010 to determine the effect of crop density on water productivity of rice crop. The study was carried out in a split-plot design with three variety as subplots and four different irrigation regimes as main plots. To model the various water productivity components, the ORYZA2000 model was used. The comparison of model results with observed data was performed using different statistical methods. The results showed that between varieties the highest amount of different water productivity WPET, WPT, WPI was measured in Hybrid and Dorfak was in second range. Also our result showed that Water productivity of Alikazemi with changes in irrigation management from I1 to I2 was decreased but in Hybrid and Dorfak change in water management had not significant Effect on water productivity because with decrease of water consumption the yield of these two varieties was decreased.