Autumn Sugarbeet Irrigation Water Optimization Basis of Yield and Cost Functions in North of the Khuzestan

For optimization autumn sugarbeet irrigation water, an experiment was conducted at Safi-Abad Agricultural Research center in the years 2010 and 2011 with silty clay loam soil.The experiment was arranged in randomized complete blocks design with three replications. Tape irrigation levels (25,50,75,100 and 125% of water requirement with T25,T50,T75,T100 and T125 respectively) and furrow irrigation was conducted. Production, cost and water function and thresholds indexes basis of irrigation depth was compared and computed. Although full rrigation in field experiment(T100 treatment) and maximizing level of applied water index(Wm) had maximum yield, T100 treatment had not significant difference with T75 and T50 treatments. On the other hand irrigation water application depth in water limited condition (Ww) was almost equal to minimum rate of water application,T25 treatment. Although Ww index had not maximum net benefit per unit of irrigation water, caused to decrease 43 percent consumed water and 21 percent of root yield and caused to increase sugare content and decrease irrigation costs. The results showed that in a view economic deficit irrigation in North of Khouzestan climatic conditions was applicable.