A field experiment was carried out in new alluvial zone of West Bengal under rabi season to find out the effect of different tillage methods and integrated weed management practices on survival and population of total bacteria, actinomycetes and fungi in rhizosphere soil of wheat. Two methods of tillage practices were adopted viz. conventional tillage and zero tillage under the experiment. Whereas four different integrated weed management treatments namely two hand weeding at 15 and 30 days after sowing (DAS), one hand weeding at 15 DAS followed by application of post-emergence chemical herbicide (ready mixture of sulfosulfuron & metsulfuron methyl) at 30 DAS, one mechanical weeding at 15 DAS followed by application of same post-emergence chemical herbicide at 30 DAS and application of pre-emergence botanical herbicide (1:1 bamboo and parthenium aqua's extract) at 2 DAS followed by one mechanical weeding at 15 DAS were tested along with a weedy check. The result of the present investigation showed that maximum population of different microorganisms were recorder under zero tillage over conventional tillage throughout the experimentation. On the other hand; application of post emergence chemical herbicide suppressed the microbial population between 0 to 7 days after application (DAA), whereas minimum microbial population were observed in between 3 to 15 days after application of botanical herbicide during both the years under the investigation. Two hand weeding treatment produced significantly higher microbial populations over weedy check in most of the cases throughout the investigation.