The effect of pyrasosulfuron ethyl (10% WP), bensulfuron methyl (0.6%), pretilachlor and POE bispyribac sodium (10% EC) on soil microflora and soil enzymes under rice-rice ecosystem in long term herbicide trial were studied during Rabi 2015-16 and 2016-17 and Kharif 2015 and 2016. The soil samples were collected from the experiments conducted at Wetland, TNAU by AICRP-Weed Management unit, Coimbatore. The results of the pooled data of two season revealed that all the four herbicides viz., PE pyrasosulfuron ethyl (10% WP), bensulfuron methyl (0.6%), pretilachlor and POE bispyribac sodium (10% EC) reduced the soil microflora except actinobacteria and soil enzymes upto 5 days after herbicide application. Simultaneouly the mciroflora were increased 10 times after 15 days herbicide application when compared with hand weeding. The treatment, bensulfuron methyl (0.6%) along with pretilachlor (6.6%) fb hand weeding significantly increased the microbial population and soil enzymes during Rabi seasons. In kharif, pyrasosulfuron ethyl fb bispyribac sodium recorded the highest microbial population followed by pyrasosulfuron ethyl fb hand weeding. But the activity of soil enzymes viz., alkaline phosphatase and dehydrogenase and Urease were significantly highest in the treatment, pyrasosulfuron ethyl fb hand weeding followed by PE pyrasosulfuron ethyl fb POE bispyribac sodium compraed with unweeded check. The phylogenetic analysis of 16s rDNA from 20 bacterial colonies revealed that the all the 20 bacterial colonies were identifed as Bacillus sp.

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