Evapotranspiração real da cultura do milho (Zea mays, L.) em lisímetros de drenagem e sua comparação com métodos empíricos.

Abstract

To determine actual evapotranspiration for corn, a study was done at the Hydraulics and Irrigation Laboratory, Pici Campus, Federal University of Ceará, Brazil, using a battery of drainage lysimeters. Correlations between actual evapotranspiration for corn determinated by lysimetry and by empirical methods was stablished, in order to find a more simple and reliable empirical method to determine evapotranspiration for the crop. The actual evapotranspiration for corn, determined by lysimetry, ranged from 2,85 mm/day for the first days of the cycle, to 10,17 mm/day for the last 30 days of the crop cycle. As a term of comparison, evaporation from a ''Class A" tank, at the same area, averaged 8,75 mm/day. Among the various methods to determine evapotranspiration compared with drainage lysimetry, Blaney-Criddle, Solar Radiation and Fao - Class A tank, shown the best correlations; they also need only a few climatic data and are very ease to use.