Impact of Pre and Post Emergence Herbicide Application on Soil Microbial Population Assessment in Direct Wet Seeded Rice

Abstract

Direct wet seeded rice is eminent due to low energy and cost required for the cultivation. The only disadvantage is difficulty to manage weeds due to which farmers rely mostly on herbicides for the effective management. Herbicides are bioactive compounds which will affect the soil microflora by its ecotoxicological behaviour. Hence, in this study herbicides such as pendimethalin, pretilachlor + pyrazosulfuron ethyl (tank mix) as pre-emergence and bispyribac sodium + ethoxy sulfuron (tank mix), penoxsulam + cyhalofop butyl (ready mix), trifamone + ethoxy sulfuron (ready mix), bispyribac sodium as post emergence herbicides in their regular dosage were evaluated for their impact on soil microbial population viz; bacteria, fungi and actinomycetes. The results revealed that these herbicides affected the microbial population during the initial days but later the population was regained at 55 DAS which indicates the reduction in toxicity level of the applied herbicides.