Document Type : Research Paper
This study investigated the effect of water stress and different amounts of zinc, manganese, and boron fertilizers on yield components and water use efficiency of sugar beet. The experiment was conducted for three years in Qazvin, Iran, with two-factor factorial design in randomized complete block and three replicates including irrigation and fertilizer treatments. Irrigation treatments consisted of four intervals i.e. 6, 9, 12 and 15 days (treatments E1 to E4) and fertilizer levels included fertilizers based on soil test (30 kg boric acid/ ha , 40 kg zinc sulfate / ha and 30 kg manganese sulfate /ha,), 30 percent less than the recommended fertilizer (21 kg boric acid/ ha ,28 kg zinc sulfate /ha, 21 kg manganese sulfate /ha) and 30 percent more than the recommended fertilizer (39 kg boric acid / ha , 52 kg zinc sulfate /ha and 39 kg manganese sulfate / ha) treatments, respectively, F1, F2, and F3. Statistical analysis of sugar beet root yield showed significant (at 5% level) differences between irrigation treatments and fertilizer treatments. Treatment E1F3 produced a yield of 64696 kg/ ha, while E4F3 produced 41736 kg/ha that was the lowest yield. Average root yield of F2 treatmentswas more, but, in the case of F1, the amount of sugar level was higher. In the wettest irrigation treatment, root yield increased with increasing fertilizer rates. It is suggested that when water stress conditions occur, use of fertilizer in excess of the recommended levels should be avoided. The volumes of irrigation water applied in irrigation intervals of 6, 9, 12 and 15 days were, respectively, 9659, 8104, 6677, and 5398 cubic meters per hectare. Water productivities for irrigation interval of 15 days and F2, F1, and F3 were, respectively, 8.39, 8.38, and 7.73 kg beetroot per cubic meter of water, reflecting the most efficient use of irrigation water.