Azolla and urea application in a rice field transplanted with square (20 cm .times. 20 cm) and rectangular (10 cm .times. 40 cm) spacings for three consecutive seasons were found to increase significantly uptake of N and P by the rice plants, irrespective of seasons. Azolla treatments increased the organic C content of the soil during both wet and dry seasons, while its N and P contents were more only during the wet seasons. Urea did not affect N, P and organic C contents of the soil. Spacing had no significant effect on N and P uptake by the rice plant or N, P and C contents of the soil. Maximum N and P uptake in rice were obtained by growing two crops of Azolla after transplanting in addition to its incorporation before transplanting. This treatment showed significantly more N uptake than the urea at 60 kg N ha-1 during wet and dry seasons of 1982. Among Azolla treatments, twice Azolla dual cropping although showed comparatively lower uptake of N and P, it was comparable to that of 60 kg N ha-1 urea.