Fixation of Nitrogen by the Rice Plant

Abstract

APPRECIABLE work has been done by P. K. De¹, Uppal et al. ² and Chaudhuri H.³ on the fixation of nitrogen by blue-green algæ in rice soil. Further work by Watanabe et al. ⁴ revealed that some specific algæ fix nitrogen in rice soil. Watanabe⁵ showed that a few species, for example, Tolypothrix tenius, Calothrix brevissima and Anabaenopsis sp. seemed to have greater ability to fix atmospheric nitrogen than the usual blue-green algæ. So it is clear as most of the rice soil devoid of these specific blue-green algæ can support rice plants and also maintain the nitrogen level more or less constant there must be other sources for nitrogen recuperation. Rain water alone cannot account for this. Sahasrabuddhe⁶ showed that the presence of growing rice roots helps in fixing nitrogen in the soil. Sen⁷ suggested the presence of nitrogen-fixing organisms living symbiotically in the roots of rice plant. Viswanath⁸ also suggested that the rice plant can fix atmospheric nitrogen.