Abstract
The efficiency of Sesbania cannabina as a green manure for rice was studied by considering the production and decomposition of the legume in three soils after 45, 55 and 65 days of growth. The green manure, raised as a catch crop in wheat-rice rotation, added on average 18, 28 and 37 t ha-1 of green matter and 98, 147 and 165 kg N ha-1, respectively, at the three growth stages. The grain yield of rice transplanted immediately after turning under the green manure, irrespective of its stage of growth, was equivalent to 100-120 kg ha-1 of chemical N. Differences in N uptake by the rice crop under manured and fertilized conditions were not significant. There was rapid C and N mineralization in the legume whose incorporation at the mature stage alone (65 days) contributed to a residual status of the elements in the soils after the rice harvest.