Evaluation of reference-crop evapo-transpiration by empirical method for predicting consumptive water use of a crop in a tropical wet-and-dry climate

Abstract

Reference-crop evapo-transprration (ETo) was determined according to 4 empirical methods using climatic data for
the different phenological stages ofmaize (Zea mays L.) grown during the rainy seasons of 1992-95. Evaluation of the
empirical methods for the prediction of crop-consumptive water use (ET_crop) was based on the variability of derived ETo estimates and the capability of each estimate to reliably predict the (ET_crop) during the different phenological stages of
growth. The modified Penman method effered the best result with significant (P = 0.01) coefficient of determination of (ET_crop. Next to Penman is the modified pan-evauoration method. The modified radiation method was graded next and lastly the moditied Blaney-Criddle approach. The relative reliability of each method in terms of accuracy of both
measured and extrapolated meteorological data utilized is also discussed.