Add to ORKGNot AvailableSurface energy balance, water use efficiency and radiation utilization efficiency of sunflower were studied under different sowing dates and irrigation regimes in Bahasuni watershed, Dhenkanal, Odisha. The latent heat flux of the crop varied with the photo-thermal environments and values ranged between 8.64 to 18.77 MJ m day under different treatments. It was revealed that during mid-growth stage when canopy was fully developed and water did not limit transpiration (wet soil), latent heat flux consumed most of the energy from net radiation. As the soil dried towards maturity, water became less available for evapotranspiration and the energy was used mostly for heating the soil (soil heat flux) or heating the air (sensi...