ORGANIC DEBRIS AS MICRO-SITE FOR NITROGEN-FIXATION

The importance of non-symbiotic N2fixation in the reduced layers of submerged paddy soils was stressed in previous papers by field surveys (1, 2) and model experiments in the laboratory (2, 3). In these investigations, the activity of the non-symbiotic N2fixation in the manured plots was found to be higher than that in the non-manured plots. Now, it is rather well established that fairly large part of soil organic matter exists in the form of organic debris in paddy soils (4), that the amount of organic debris is larger in manured plots than in non-manured plots (5) and that soil microbial activities are high on and around the organic debris (6). The organic debris might be the active micro-sites for non-symbiotic N2fixation. The experiment conducted on this assumption will be described in the present paper. © 1979 Taylor & Francis Group, LLC.