DETERMINATION OF CROP COEFFICIENTS OF MAIZE FOR THE ESTIMATION OF CROP WATER USE

The crop coefficients (kc) of maize were determined for the growing season of month June to mid September. A hydraulic weighing lysimeter in National Centre for Agricultural Mechanization (NCAM) was used to determine the crop evapotranspiration (ETcrop) for maize while meteorological data from the weather station at NCAM was used to compute reference crop evapotranspiration (ETo) and potential evapotranspiration ETp.Decade and monthly values of crop coefficients (kc) for maize were obtained by determining daily values for and then averaged over ten day period and thirty day period for the decade and monthly values respectively. The crop coefficients (kc) obtained for maize during the growing season ranged between 0.4 and 0.9. A high potential evapotranspiration value for maize was established from a high value of crop coefficient, while low values of temperature and sunlight hours resulted into low evaporation rate. It is evident from this research that the determination of crop evapotranspiration and the effects of weather conditions are essential for the estimation of crop water use.