Biological nitrogen fixation by epiphytic microorganisms in rice fields.

Epiphytic-microorganisms have been observed on shallow wetland rice, deepwater rice, and on weeds growing in rice fields. In the wetland rice field ecosystem, microorganisms epiphytic on rice and weeds make a limited contribution to the nitrogen input but blue-green algae play an important role providing an inoculum for the regeneration of the algal blooms that are periodically affected by adverse co~ditions. In deepwater rice, which offers a much greater biomass for colonization, the contribution of nitrogen by the epiphytic BGA is of agronomical significance...