The present research work was conducted to study the suitability and potential of azolla (Azolla pinnata) in augmentation biogas and slurry in the Deptt. of Soil Sci. & Agric. Chemistry, College of Horticulture, KAU, Thrissur, during the period 2010-2012. Co-digestion of cow dung and azolla (Azollapinnata) in the ratio 1:0.5 in floating drum plants of 0.5 m3 capacity produced maximum volume of biogas (0.29 m3 kg-1 TS) as against 0.21 m3 kg-1 TS obtained from cow dung alone treatment in 26 days, recording an increase of 27.58%. The Hydraulic retention time, an indication of completion of digestion, could be reduced by six days upon using azolla as co-substrate. Mixing azolla with cow dung in equal ratio increased the nitrogen content of slurry by 50% than in its absence. Response of rice variety Jyothy to the enriched manure revealed that the grain (44.97 g pot-1) and straw (72.73 g pot-1) yield was maximum when the crop was nourished with enriched manure II in association with the recommended dose of chemical fertilizers. Crop uptake of N (4260 mg pot-1) and K (4263 mg pot-1) was also the highest in this treatment.