Using four varieties cultured in a normal season or the late planting, theefficiency for Solar energy conversion of a rice population was measured undernatural conditions for 2 to 3 weeks period of the ripening stage.
The absorbed photosynthetic active radiation was obtained from short wavesolar radiation, and gross chemical energy fixed by the population was obtainedfrom adding the net production(dry matter increment) to the estimated dark respiration.
The efficiency for Solar energy conversion thus determined was ranged from 4.1 to 1O.2% based on gross production(Eg) ; 1.2 to 5.7% based on net production(Ea), and found to be higher in the late cool season than the hot July or early August.