LAUSR

ABSTRACT The objective of this study was to evaluate the stalk yield, sugar yield and technological quality of two varieties of sugarcane under different irrigation depths and nitrogen doses. The experiment was conducted in two consecutive years (2015 and 2016) at Olho D’Água Farm, in Itambé, Pernambuco, Brazil. The experimental design was randomized blocks in the split-split-strip-plot scheme, with four replicates. Treatments consisted of four irrigation depths (L1 = 12, L2 = 45, L3 = 100 and L4 = 125% of the crop evapotranspiration - ETc, plant cane) and (L1 = 10, L2 = 40, L3 = 100 and L4 = 125% ETc, ratoon cane), four doses of nitrogen (N1 = 0, N2 = 50, N3 = 100 and N4 = 200 kg ha-1 of N) and two varieties of sugarcane (RB92579 and RB002754). Sugarcane plants irrigated with the highest depths of 1,324.06 and 1,242.3 mm in the plant cane and ratoon cane cycles respectively produced 38.40 and 49.14 t of stalks ha-1 and 0.48 and 1.82 t of sugar ha-1 more, compared to those irrigated with the lowest depths of 124.06 and 99.4 mm. The highest stalk yield was obtained with the combination of 120.7 kg ha-1 of N and 1266.6 mm of irrigation depth. Sugarcane technological quality is positively correlated with the increase of the irrigation depth in the plant cane and ratoon cane cycles and negatively correlated with nitrogen.