Biomass generation is of primary importance in organic farming system to achieve the higher yield and to maintain good fertility. A field experiment was conducted during kharif 2012-13 and 2013 -14 on effect of organic farming on productivity of rice and soil fertility under alfisol at Organic Farming Research Centre, ZAHRS, UAHS, Shimoga, Karnataka. The results of the study revealed that FYM applied for rising of green manures as in-situ recorded significantly higher green biomass yield. The 100 per cent recommended N(100 kg N/ha) equivalent to FYM applied at sowing of Sesbania aculeata recorded 21.92 ton /ha green biomass yield followed by 100 per cent recommended N equivalent to FYM applied to soil at sowing of mixed green manures (Sesbania aculeata + Crotolaria juncea + Vigna unguiculata ) recorded 17.25 ton/ha. Maximum grain (46.58 q/ha) and straw yield (80.65 q/ha)) of paddy as well as soil organic carbon, available N, P2O5 , K2O, S and soil microorganisms were recorded in 100 per cent N through FYM applied at sowing of mixed green manures + FYM(@10 ton/ha) at in-situ incorporation of raised green manure biomass followed by 100 per cent N through FYM applied at rising of Sesbania aculeata + FYM @10 t/ha applied at incorporation.