Microflora population and physico-chemical properties of potato-cropped soil as influenced by oxyfluorfen 23.5% EC

Abstract

The effects of Oxyfluorfen 23.5% EC on microflora population and soil physico-chemical properties in potato were investigated over two seasons (2008-9 and 2010-11). The treatments are as follows: oxyfluorfen 23.5% EC @100, 200 and 300 g a.i. ha-1 as pre- emergence, atrazine @ 1000 g ha-1 as pre-emergence, pendimethalin @ 1500 g ha-1 as pre-planting incorporation, farmer practice (hand weeding twice at 15 and 30 DAP) and unweeded control. Among all the treatments, oxyfluorfen@ 300 g a.i. ha-1 recorded minimum weed population as well as biomass. Potato tuber yield was maximum in oxyfluorfen 23.5% EC @ 300 g a.i. ha-1 (35.032 t ha-1) which is statistically at par with oxyfluorfen 23.5% EC @ 200 g a.i. ha-1 (34.706 t ha-1). Excluding atrazine @ 1000 g ha-1 and pendimethalin @ 1500 g ha-1, no phytotoxicity in potato plants was observed in the herbicidal treatments. Bulk density, water holding capacity, moisture content, soil pH, organic matter content, electrical conductivity, as well as total nitrogen, available phosphorus and available potassium contents were analyzed along with microflora population (total bacteria, actinomycetes and fungi). Soil physico-chemical properties were unchanged. Though, herbicide treatments resulted in decreases in microbial counts initially but with the degradation of applied herbicides within a considerable time, the population even exceeded later than the initial count.