COMPARISON OF METHODS FOR DETERMINING EVAPOTRANSPIRATION RATE ON CASSAVA FARM IN BENUE NORTH CENTRAL NIGERIA

Abstract

Evapotranspiration (ET) is the combined processes of evaporation from soil and plant surfaces and transpiration from plant tissues. Its rate is a very significant factor for supporting irrigation management decisions. Many mathematical models have been developed to explain its behavior and to determine the ET rate. In this study, the rate is estimated using the Bowen Ratio (BR) method, which is based on characteristics of the energy budget associated with atmospheric fluxes. All necessary parameters were measured at the experimental site located in a cassava farm in Benue State from June 2005 to May 2005. The BR results were then compared with the results obtained by the modified Penman-Monett (MPM) method. The comparative results showed that measurements from BR are lower than those of MPM. In terms of economic feasibility, the BR method is more suitable than the MPM method for irrigation planning.