The impact of nitrogen-fixing blue-green algal (BGA) strains, namely
Anabaena variabilis, Aulosira fertilissima, Nostoc muscorum
, was studied at different levels of nitrogen fertilizer on specific soil parameters such as microbial populations, pH, EC, redox potential, chlorophyll, dehydrogenase and nitrogenase activity under a rice crop. The inoculation of the soil with BGA strains resulted in higher microbial populations (BGA, bacteria, fungi and actinomycetes) and had a significant influence on redox potential. A significant increase in soil chlorophyll, dehydrogenase and nitrogenase activity was observed during crop growth due to BGA application.