Fraction of Thermal Units as the Base for an Evapotranspiration Crop Coefficient Curve for Corn

We then performed linear regression of estimated ET rates against measured ET rates (water balance technique) for each cultivar. All regression equations and coefficients were significant at P<0.001. The hypotheses that intercept equals zero and slope equals 1 could not be rejected for any of the cultivars. The use of fraction of thermal units as the crop coefficient base scale allowed for a general and accurate use of the basal crop coefficient curve across corn cultivars requiring various thermal unit totals from emergence to physiological maturity