Radiation utilization efficiency and surface energy exchange of winter maize (Zea mays L.) under different irrigation regimes

Knowledge of resource capture particularly, energy, nutrients and radiation by crop species under different management practices helps in improving productivity of any crop.Growth and yield of any grain crop are largely determined by intercepted photosynthetically active radiation (IPAR), the efficienc y of conversion of it into dry matter (RUE) and partitioning of dry matter to grain. In this investigation IPAR, RUE andenergy flux of the winter maize were studied and relationships were established among biomass, yield, RUE and IPAR under different irrigation (120, 180, 240, 300, 360 mm) and nitrogen (30, 60, 90, 120, 150 kg ha-1) levels. Simulation models that rely on RUE for biomass accumulation can use these relationships for predicting biomass and yield of the crop. The RUE of the crop ranged from 1.01 to 2.16 g MJ-1under different irrigation and nitrogen levels whereas, latent heat flux varied with the growth stages and values ranged between 8.64 to 18.77 MJ m-2 day-1.