Using area-average sensible heat fluxes measured with the large aperture scintillometer(LAS), in addition to the net radiation obtained with net radiometers, the latent and soil heat fluxes can be calculated with energy balance equations. Field tests showed there was a good agreement between sensible heat fluxes obtained from an LAS and an EC system. The correlation coefficient was better than 0.8 for daytime in plant canopies. The sensible heat decreased, whereas the evaporation on the surface of the canopy attained its maximum at midday. For applications in which accuracy and area-average are of critical importance for agricultural meteorology, the LAS would be a better choice.