Foliar Fertilization Improves the Nitrogen Nutrition of Sugarcane

Increasing the recovery of N fertilizer (RNf) is the main challenge in managing nitrogen fertilization in sugarcane. This study aimed to evaluate the efficiency of complementary foliar fertilization in managing nitrogen nutrition in sugarcane. Four fertilization managements, combining soil (5.0 and 4.5 g plot−1 of N) and foliar (1.0 and 1.5 g plot−1 of N) fertilization in up to two application events (0.5 + 0.5 and 0.75 + 0.75 g plot−1 of N), were compared with conventional fertilization (6.0 g plot−1 of N in soil). The change from 6.0 g plot−1 to 4.5 g plot−1 of N reduced the RNf by 46% before the first foliar fertilization. The RNf (26%) was similar between managements after the first foliar fertilization. After the second foliar fertilization, the RNf was 38% higher than that for conventional management. The accumulation of N in the aerial part of sugarcane was similar between managements until the first foliar fertilization. After the second foliar fertilization, the accumulation of N increased by 3.5% with foliar fertilization. The biomass accumulated by the managements was similar before and after the first and second foliar fertilization. The splitting of foliar fertilization increased the accumulation of N and RNf by 22% and 24%, respectively. The fertilization management with 4.5 g plot−1 of N applied to the soil, with two applications of 0.75 g plot−1 of N on the leaf, obtained greater accumulations of N and RNf. Foliar fertilization increases the efficiency of fertilization and improves the N nutrition of sugarcane.