EFFECT OF DEFICIT IRRIGATION MANAGEMENT ON QUALITATIVE AND QUANTITATIVE YIELD OF SUGAR BEET (BETA VULGARIS L.) IN KARAJ, IRAN

Environmental pollution and food security resulting from agricultural input surpluses are of great concern to the world in recent year. Improving use efficiency of agricultural inputs becomes an important way to relieve above issues. Due to the long growing season of sugar beet, its response to deficit irrigation is very important. According to the objective, a field study was conducted to investigate the effects of conventional (control), fixed and alternate furrow irrigation on qualitative and quantitative yields of sugar beet was carried out in Karaj, Iran. The treatments were applied in two consecutive years (2013 and 2014) as randomized complete block design with three replications. The irrigation water applied in the control treatment was 1127 mm, while the fixed and alternate furrow irrigation reduced drainage by 44% and 50%, respectively. The root yield was obtained 79 t/ha under alternate furrow irrigation, and 16% higher compared to fixed furrow irrigation. Average water use efficiency (WUE) for sugar beet root production in conventional, fixed, and alternate furrow irrigation were achieved 7, 11, and 12 kg/m(3), respectively. Moreover, the maximum water use efficiency for of pure sugar production (1.5 kg/m(3) of water used) was obtained in the alternate furrow irrigation treatment. So, it was 23 and 117% higher than fixed and conventional furrow irrigation treatments, respectively. a-amino nitrogen absorption in the alternate furrow irrigation treatment increased by 29% compared to other treatments, which suggest balanced fertilization management is needed in alternate furrow irrigation. Consequently, alternate furrow irrigation management with reduced drainage achieved maximum WUE.