An experiment in randomized block design was laid out to compare the yields in different crop models (set of treatments) as influenced by the integrated effect of different sources of nitrogen including green manuring of Sesbania. The experiment was conducted during kharif season of 2002 and rabi 2002- 2003. Models viz., A: Puddled transplanted Rice-Conventional Wheat with recommended dose of fertilizers (NPK and Zn) for both; B: Green manure by Sesbania- Puddle Transplanted Rice Conventional Wheat with 180 kg nitrogen per hectare and recommended dose of PK and Zn for both; C: Puddled Transplanted Rice-Conventional Wheat with 10 per cent extra of recommended dose of fertilizers and D: Puddled Direct Seeded Rice-Zero Tillage Wheat with recommended dose of fertilizers, were taken into consideration. It was observed that green manuring model gave the highest yield. But among conventional and direct seeding methods of rice cultivation, latter gave higher yields. Moreover, green manure of Sesbania confirmed previous findings of its allelopathic effects on succeeding wheat crop thus reducing total fresh weight of weeds in the early stages of crop growth in green manure model.