Silicon fertilization reduces the deleterious effects of water deficit in sugarcane

Few studies have focused on water deficit for sugarcane, whose damage could be reduced with Si, as shown in other crops. This study aimed to determine whether Si fertilization enhances the best recovery of sugarcane after two periods of the formative phase (tillering and early grand growth) for RB86-7515 (drought tolerant) and RB85-5536 (drought sensitive), and which growth phase is beneficial for each cultivar. It was investigated: 1) the effect of Si fertilization on total Si uptake, and on soluble Si in soil; 2) whether Si uptake could provided increased stalk yield, juice quality, dry biomass compared to well-watered treatments. Two experiments were conducted in pots under greenhouse: one with RB86-7515 and another with RB85-5536. Treatments were: 1-Non-Deficit+Si, 2-Non-Deficit-Si, 3-Early Deficit (ED)+Si, 4-ED-Si, 5-Late Deficit (LD)+Si, and 6-LD-Si. Silicon fertilization provided best recovery of sugarcane (superior sugar, stalk yield, and dry biomass) after early and late water deficit compared to its absence for both cultivars. For RB85-5536, Si fertilization propitiated similar recovery for water deficit and continuous irrigation treatments. No differences were observed between periods of water deficit. Therefore, Si fertilization at planting should be considered another tool for reducing the damage caused by water deficit in sugarcane.