Abstract
In a field study to evaluate the response of rainfed lowland rice to N fertilizer-green manure applications, it was shown that a 56-day-old Sesbania rostrata pre-rice green manure crop accumulated more than 6 t above-ground dry biomass ha-1 and about 160 kg N ha-1. Consequently, green manuring alone improved the grain yield of the subsequent rainfed lowland rice crop by about 1.8 t ha -1 over that of the control. This increase was the same as that of the 60 kg N ha -l treatment. Under rainfed lowland conditions, it appears that there is no need to combine fertilizer N with S. rostrata to obtain maximum benefits. In a relatively fertile soil, it is possible that all N requirement of the rice crop other than that which could be obtained from the native soil N may be provided by S. rostrata.
