Assessment of soil microbial population dynamics and their correlation with pod yield in herbicidal treated groundnut

Abstract

The present set of experiment was carried out in the Central farm, OUAT, Bhubaneswar during Rabi 2014-15 with five treatment such as control(without weeding), Butachlor, Alachlor, Oxyflurofen as pre-emergence herbicides and weed free (manual weeding) having three replication under RBD design to study the impact of pre-emergence herbicides on microbial populations. The application of herbicides have tremendous on impacts population of bacteria and fungi in the rhizospheric soil and their enzyme activities and cause qualitative and quantitative alterations. At 90 DAHT the population of the bacteria and fungus became at par with the initial population i.e. 0 DAHT. Among the control and weed free, the population of bacteria was found highest whereas, the fungal population was moderate in the weed free as compared to other treatments. Application of pre-emergence herbicide affected the microflora population specially bacterial and fungal population. The bacterial population was found to be highest (9x105 cfu/g) in weed free where on fungal population was highest (7x103 cfu/g) in control treatment. These three herbicides showed drastic reduction in the bacterial as well as fungal population within seven days after the application. An increasing trend of the bacterial and fungal population was observed after seven days and the trend continue up to 90 DAHT. The study confirmed that the herbicides (Butachlor, Alachlor and Oxyflurophen) altered the microbial populations hence to influence pod yield by affects the different soil enzyme activities.