عنوان مقاله [English]
One of the biggest barriers for agricultural production in Iran is water deficit. However, certain optimum approaches for water application can solve this problem. Deficit irrigation technique is an approach that could have a better and economic use of water in agriculture. In this regard, a research with three factors including two irrigation intervals of 8 and 12 days, two nitrogen fertilizer levels based on soil analysis result and 2/3 use of it, and four levels of irrigation, 100, 80, 60, & 50 percent of crop water requirement, was performed on sugar beet during 1998-1999 in Mahidasht agricultural research station, Kermanshah province. The experimental design was a Factorial Split Plot with Randomized Complete Block arrangement and three replications, in which irrigation intervals represented the main plot and nitrogen fertilizer along with irrigation levels represented the sub plots. Furrow irrigation method was used and the amount of applied water was measured with a flowmeter. The combined analysis of data showed that the amount of water had a very significant effect on root yield, white and gross sugar yield. Root yields of 52.5 and 48.2 t/ha were obtained from 100 and 80 percent of crop water requirement, respectively. However, from the economic point of view, the 80 percent water requirement treatment had the highest net benefit. The irrigation intervals of 8 and 12 days had no significant effects on sugar beet yield components. Therefore, the 12 days irrigation interval was recommended. Finally, the nitrogen fertilizer treatment did not show any significant effect. There was no significant difference between the nitrogen fertilizer treatments.