Field experiments were conducted in the experimental farm of Bidhan Chandra Krishi Viswavidyalaya, Kalyani, Nadia, West">
Field experiments were conducted in the experimental farm of Bidhan Chandra Krishi Viswavidyalaya, Kalyani, Nadia, West Bengal (22o57ï‚¢ N, 88o20ï‚¢ E) during Rabi season of three years (2007-08 to 2009-10). The popular variety of the region B-9 was selected and the biomass, grain yield, leaf area index (LAI), crop height and extinction coefficient were measured for each year. The diurnal variations of net radiation (Rn), global solar radiation (GSR) and incident photosynthetically active radiation (PAR0) for different crop growth periods were studied. All the three radiation parameters showed a peak at 11.00 to 12.00 hours on an average and diurnal pattern was almost similar. The seasonal variation did not show any definite pattern. In 2009-10, the LE, G and S values were lower due to lesser amount of Rn throughout the season. In all the years no negative value of S was observed indicating that only upward movement of sensible heat flux occurred. The relationship between intercepted photosynthetically active radiation (IPAR) and biomass were also worked out. There is an immense scope of using the radiation pattern and its balance as inputs of crop growth and yield prediction model.