Effect of some soil amendments on yield and quality traits of sugar beet ( Beta vulgaris L.) under water stress in sandy soil

Two field experiments were carried out at Wadi El-Natrun, El-Beheira governorate, Egypt during 2014/2015 and 2015/2016 growing seasons. The aim of the work is to study the effect of compost and bentonite as soil amendments solely or mixed and two nitrogen rates (90 and 120 kg N/fed) on quality and productivity of sugar beet under water stresses (100, 75 and 50% of water requirements) using a drip irrigation system. The obtained results showed that increasing water stress up to 50% of water requirement significantly decreased sugar lost in molasses, root and sugar yields (ton/fed). While, it increased sucrose% and sugar extractable. Decrease nitrogen fertilizer from 100% to 75% of recommended rate (120 kg N/fed) significantly decreased root and sugar yields, however, increased sucrose % and sugar extractable. Application of 5 ton/fed compost or bentonite as well as mixed 2.5 tons/fed of each of them led to a significant increase in all studied traits. Compost followed by bentonite was the best treatments. The maximum value of root and sugar yields were produced from the interaction between irrigation without water stress and fertilization by 120 kg N/fed and application of 5 ton/fed compost in the second season