EFFECT OF REGULATED DEFICIT IRRIGATION AND BORON RATES ON SUGAR BEET PRODUCTIVITY IN NEWLY RECLAIMED SOILS

Abstract

: A field experiment was conducted at Km 71 West Nubaria, Alex./ Cairo desert Road, El-Behiera Government, Egypt, during two successive winter seasons, 2017/18 and 2018/ 19. The objective was to study the effect of five regulated deficit irrigation treatments [I 1 = No stress at all physiological stages, I 2 = skip irrigation at the beginning of development stage (60 days from sowing), I 3 = skip irrigation during development stage (90 days from sowing), I 4 = skip irrigation at mid season (120 days from sowing) and I 5 = skip irrigation at late season (150 days from sowing)], and four rates of boron fertilizer applied as boric acid,[B 1 = Without B (control), B 2 = 0.5 kg B/fed, B 3 = 0.75 kg B/fed, and B 4 = 1.0 kg B/ fed] on sugar beet yield and quality, amounts of applied irrigation water and water utilization efficiency. The results showed that irrigation treatments and boron rates had a significant effect on root, shoot and sugar yields. The obtained results indicated that the reductions in root yield were 9.55, 6.43, 5.58 and 0.84 t/fed, while for sugar yields were 1.89, 1.34, 1.22 and 0.10 t/fed for I 2 , I 3 , I 4 and I 5 , respectively compared to no stress treatment. The results showed that the combined effect of irrigation treatment I 1 (no stress at all stages) and boron fertilizer rate B 2 (0.5 kg B/fed) gave the highest average values of root yield (35.041 t/fed) and sugar yield (6.315 t/fed) over the two seasons. On the other hand the average amount of applied irrigation values were 2145, 1929, 1822, 1858 and 1895 m 3 /fed for the I 1 , I 2 , I 3 , I 4 and I 5 irrigation treatments, respectively. Likewise, the highest average water utilization efficiency for sugar beet root and sugar yields of 16.523 kg root/m 3 water applied and 2.951 kg sugar/m 3 water applied were obtained with the irrigation treatment I 5 (skip irrigation at late season stage) and boron fertilizer B 3 (0.75 kg B/ fed) over two seasons. It could be maintained herein that the no stress irrigation water I 1 , with 0.75 kg B/fed treatment achieved the highest yield of sugar beet (root and sugar) of the availability of sufficient irrigation water. Otherwise it is suggested to follow the irrigation treatment I 5 (no irrigation at late season) and applying boron fertilizer at rate of 0.75 kg B/fed obtain high sugar beet yields.