The effect of individual and combined application of biofertilizers, v
iz. Azospirillum, Azolla and blue green algae with and without inorgan
ic nitrogen on rice (Oryza sativa L.) was investigated under lowland c
ondition both at research station and farmers' field. Nitrogen levels
and cropping seasons were found to influence the biofertilizers effect
. Azospirillum responded well at 75 kg N/ha by showing 18% increased g
rain yield over the control. Azolla and blue green algae showed the ma
ximum grain yield of rice at 50 kg N/ha when applied individually. Azo
sprillum performed better in rainy, summer and winter seasons. Azolla
performed well during summer and winter seasons and EGA during rainy s
eason. Azospirillum efficacy could be improved even at 125 kg N/ha whe
n inoculated in soil incorporated with 3 tonnes/ha Sesbania rostrata.
Triple combination of Azospirillum, Azolla and EGA responded well at 5
0 kg N/ha for summer season and at 75 kg N/ha for winter and rainy sea
sons, indicating a varied response of biofertilizers to N levels and s
eason.