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 [I1 = No stress at all physiological stages, I2 = skip irrigation at the beginning of development stage (60 days from sowing), I3 = skip irrigation during development stage (90 days from sowing), I4 = skip irrigation at mid season (120 days from sowing) and I5 = skip irrigation at late season (150 days from sowing)], and four rates of boron fertilizer applied as boric acid,[B1 = Without B (control), B2 = 0.5 kg B/fed, B3 = 0.75 kg B/fed, and B4 = 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 I2, I3, I4 and I5, respectively compared to no stress treatment. The results showed that the combined effect of irrigation treatment I1 (no stress at all stages) and boron fertilizer rate B2 (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 m3/fed for the I1, I2, I3, I4 and I5 irrigation treatments, respectively. Likewise, the highest average water utilization efficiency for sugar beet root and sugar yields of 16.523 kg root/m3 water applied and 2.951 kg sugar/m3 water applied were obtained with the irrigation treatment I5 (skip irrigation at late season stage) and boron fertilizer B3 (0.75 kg B/ fed) over two seasons. It could be maintained herein that the no stress irrigation water I1, 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 I5 (no irrigation at late season) and applying boron fertilizer at rate of 0.75 kg B/fed obtain high sugar beet yields.