RATOON SUGARCANE YIELD INTEGRATED DRIP-IRRIGATION AND NITROGEN FERTILIZATION

The aim of this study was to compare the use of water and nitrogen on ratoon sugarcane during irrigated and rain-fed conditions, and to assess the production potential of stalks and sugar with different rates of N-fertilizer on the subsurface drip-irrigated management. The experimental design was a randomized block with four replications for each experiment and treatments: (T1) irrigated, 0kg N ha(-1); (T2) irrigated, 70kg N ha(-1); (T3) irrigated, 140kg N ha(-1); (T4) irrigated, 210kg N ha(-1); (T5) not irrigated, 0kg N ha(-1), and (T6) not irrigated, 140kg N ha(-1). Biometric, technological, dry matter and yield variables were analyzed among the treatments. The irrigation system together with the application of N-fertilizer at 140kg ha(-1) presented significant differences in dry matter accumulation of shoots, and for the production of stalks and sugar, respectively 94, 105 and 106%, higher when compared to the not irrigated, without N-fertilizer (T5). There was a positive and synergistic effect of irrigation with N-fertilizer on the productivity of stalks and sugar. Ratoon sugarcane irrigated with subsurface dripping had the highest yield (22Mg ha(-1) of sugar) with the dosage of 140kg ha(-1) N.