Eficiência de uso da água no cultivo de cana-de-açúcar, 1ª folha, em diferentes épocas de plantio

Abstract

Globally, irrigation constitutes the human activity with increased freshwater demand. In this sense, it is necessary strategies that reduce the most of this consumption. Irrigation of sugarcane, an alternative is to synchronize the phenological stage of the plant that requires more water, the season of greater water availability in the region, reducing spending on irrigation and reducing costs in production. Thus, the aim of this study is to establish time of sugarcane plantations, second sheet, which results in greater efficiency of water use, when considering the summer planting of Northeastern Brazil. For this, two experiments were conducted, evaluating two varieties RB92579 and RB962962 cane. The experiments were conducted in the commercial area of plant Cururipe SA using subsurface drip irrigation system. The experimental design was a randomized block design with four replicates per variety, with the treatment the planting dates: E1-October, E2-November, E3-December 2013, E4-January and E5-February. At the end of the crop cycle were evaluated physical and technological yields of the crop. Efficiency in water use (USA) for each treatment was defined as the ratio between the physical performance (TCH) or technological (TAH) culture and the volume of water that entered the system, either through irrigation, the total rainfall or effective rainfall. In both varieties of sugarcane, the E1 and E4 treatments had the highest values of TCH and TAH. The variety RB92579 both planting October as the January showed greater US. The variety RB962962 the largest US using as a basis the TCH was in the months of October and January, already in base TAH were the months of November and January. The months of planting that maximized the net of the production system of sugarcane revenues were October and January for the variety RB92579 and the variety RB962962 plantations November and January.