A pot experiment was conducted to investigate the effect of Azospirillum brasilense Sp. 7 on growth and nitrogen fixation (nitrogenase activity) in Cynodon dactylon wider different water regimes. Imposition of water stress considerably affected plant growth, in situ root nitrogenase activity, rhizosphere population of Azospirillum, per cent root infection by Azospirillum and nitrogen content of host plant. Maximum values of all the above parameters were recorded in the plants subjected to watering once in 24 hr compared to watering once in 48, 72,96 hr and water logged conditions.
