تاثير برنامه ريزي آبياري بر بهره وري آب در كشاورزي (مطالعه موردي در شبكه آبشار اصفهان)

Impact of irrigation scheduling on agriculture water productivity

Water resource limitation, irrigation scheduling, undesirable and non economical water use are the most important limiting factors of agricultural development and production in Iran. For desirable and optimum use of water different themes are under discussion; irrigation scheduling, improvement in on farm water management, improve in water productivity and water economy profitability. This study was conducted to determine propose irrigation scheduling (time and depth) for wheat and barley under different water quality and quantity at field scale to improve water productivity in Abshar network in Esfahan. Optimal irrigation depth, schedule and yield - water- salinity function for wheat and barley was defined using combined fixed and variable cost, yield fees, on farm and simulated data for different water quality and quantity. Accordingly, crop yield and water productivity of wheat and barley simulated and compared to the on farm condition. Result indicated that wheat and barley yield increased 15 percent by improve in irrigation scheduling. In the other hand with improve agronomic management and decrease 20 percent of irrigation depth, crop yield variation was very low. As a consequence, optimal irrigation depth increased when irrigation water salinity increased, but differences in optimal irrigation depth decreased under limitation of water and land. Increase in applied irrigation water until optimal depth caused economic water productivity increased, but water applied more than optimal level has no significant effect on water productivity and economic water productivity. According to the results, proper irrigation scheduling together with improved agronomic management, increased crop yield and water productivity about 16 and 45 percent, respectively.