Necessidades hídricas da cana-de-açúcar cultivada em clima tropical

Abstract

An accurate estimation of water consumption of cane sugar crop is important for maximum productivity with less investment. The objective of this study was to determine the water requirements of sugar cane grown in tropical environments. The field experiment was carried out in Paraiba state, during the productive cycle of sugar cane crop variety RB 92 579 irrigated by central pivot irrigation (sprinkler) from October 2009 to September 2011. The crop evapotranspiration was obtained based on soil water balance and reference evapotranspiration by Penman-Monteith method (FAO/56), using the data of air temperature, relative humidity, wind speed and solar radiation from Data Collection Platform, next to the experimental site. Soil water moisture was monitored by TDR probes (Frequency Domain Reflectometry), Model PR2/6, Delta-T. The results showed that the crop coefficients values proposed by the FAO for sugar cane are not suitable for tropical regions. The water consumption of sugar cane ranged from 2.6 mm day-1, at initial crop growth stage, to 6.38 mm day-1, with an average of 4.3 mm day-1 for all cycle. Similarly, the crop coefficient ranged from 0.56 to 1.43, with an average of 0.99 for the same development crop growth stages.