A method for estimating crop actual evapotranspiration

The reliability of Rhenals and Bras (1981) model in estimating actual evapotranspiration in Samaru for a wheat crop was tested and result is herein presented. This model incorporates climate, crop and soil characteristics factors in estimating actual evapotranspiration. Actual evapotranspiration values estimated using the model were compared with actual evapotranspiration amounts estimated from open pan evaporation data. The mean difference between the average aily evapotranspiration obtained by Rhenals and Bras (1981) model and those from open pan evaporation data was 0.20 mmday-1 and was not statistically significant at 0.05 level of significance. The tested model is found reliable in estimating the crop actual evapotranspiration