Water requirement and crop coefficients of sorghum in Apodi Plateau

ABSTRACT Sorghum is of significant economic importance for Northeastern Brazil, since it exhibits high growth rates in regions with irregular rainfall distribution and temperatures, an alternative to corn, which has greater water requirements. Despite being a traditional crop the region, there are few studies on irrigation management Apodi plateau. The aim this study was determine evapotranspiration coefficient (Kc) different stages sorghum two cycles, establish relationship between Kc normalized difference vegetation index (NDVI) obtained by radiometry. Two weighing lysimeters were used estimate (ETc). Reference (ETo) estimated Penman-Monteith method (FAO) determined using methodologies: simple dual Kc. Total cycles 452 557 mm. ETc value 23% higher second cycle compared first. maximum values first 1.21 1.35, respectively, methodology. linear found NDVI allows monitoring estimating requirements crop.