Sugarcane Productivity under Drip Irrigation in Brazil: Varieties, Irrigation Depths and Ripening Processes

Abstract. Sugarcane is a very important bioenergy crop for Brazil and drip irrigation a major tool for increasing its productivity. The experiment was conducted at "Luiz de Queiroz" College of Agriculture (USP) in Piracicaba-SP. Treatments were arranged in a factorial design (4x4x8) with split-split-plot with three replicates, totaling 128 treatments and 384 plots. The evaluated irrigation depths (L50, L75 and L100 L125) were variations in the fraction applied over time, relative to the L100 treatment where soil moisture remained close to field capacity (θcc) throughout the experiment. Each tested variety had its own reference L100 based on digital tensiometer readings and datalogger acquisition system. The intensities of water deficit during maturation were evaluated for M1 (moderate water deficit of long duration), M2 (intensive water deficit of long duration), M3 (no water deficit) and M4 (severe water deficit of short duration). The sugarcane yield (TCH) was favored by the combination L100 and M3, regardless of the studied variety, with an estimated average value of 232.2 t ha^-1. Among the varieties, V4 had the highest TCH, with average of averaging 250.4 t ha^-1 for L100. The V1, V2, V4 and V6 varieties, for irrigation depth L100, did not differ significantly for TCH and had the highest average¹. Thus, one should consider the possibility of full drip irrigation, instead of the deficit one, for sugarcane.