Association of Agrometeorologists

Phenology, latent heat flux and evaporative fraction in sunflower under different photo-thermal environments

GOURANGA KAR andASHWANI KUMAR

Sunflower was grown in four different sowing dates with 3 irrigation regimes to create different photo-thermal environments. Duration of important phenological stages and productivity were found to be higher in winter sown crop which might be attributed to optimum photo-thermal environment. Crop duration and productivity were reduced when temperature increased during summer and rainy seasons. The day length was found to be influential at vegetative stage but no role was found in reproductive phase of the crop. The latent heat flux varied with the crop growth stage and moisture availability ranged between 8.55 to 19.11 MJ m-2 day-1 in different years and cropping season. During pick growth stage (47-97 DAS), ET consumed most of the energy, as a result evaporation fraction (EF) was higher during those days which ranged between 80-93% under different sowing dates in the first year and between 70-95% in different growth stages of second year

Sunflower, phenology, radiation use efficiency, crop water use, energy balance