Observations on nitrogen-fixation by some blue-green algae and remarks on its potentialities in rice culture

The results of experiments in connection with the estimation of nitrogen fixed by four species of blue-green algae are presented and discussed. The species tested were Tolypothrix campylonemoides, Nostoc sphaericum, N. amplissimum and Westiella sp. of these, Tolypothrix was the most efficient. The quantity of extra-cellular nitrogen liberated has also been estimated; this is only a fraction of the whole. The potentialities of using blue-green algal species in rice culture are discussed. It is indicated that blue-green algae could be employed as a substitute for nitrogen fertilizers such as ammonium sulphate, for rice culture in waterlogged conditions