IN-VIVO ASSESSMENT OF SOIL ENZYMES OF DIFFERENT HERBICIDES IN PADDY CULTIVATED SOILS AND ITS RISK ASSESSMENT

Abstract

Soil enzyme activities are the conservative communication of the soil community to metabolic desires and obtainable nutrients. The purpose of this research is to evaluate the changes and recovery of soil enzymes activity at regular intervals, after the sequential application of herbicides of Pretilachlor 50% EC, Pyrazosulfuron ethyl 10% WP, Bispyribac sodium 10% SC and Penoxsulam 21.7 SC in transplanted paddy field. Two experimentswith three replications were conducted at experimental farm of IIBAT, Padappai, during Kharif season of 2016 and 2017. The soil samples were collected at the following intervals of 0, 6, 10, 15, 18, 23, 25, 45 and 60 days after treatment for estimation of soil enzymes activity. All the samples were processed and analyzed for the enzyme activity by a validated UV spectrophotometric method. The results exposed that the effects of herbicides on soil enzyme activity was decreased suddenly after application of herbicides and it was slowly increased after three to five days of herbicides application. Herbicide treated plots were comparable to non-herbicide treated plots with respect to selected soil enzymes of Dehydrogenase, Urease and Alkaline Phosphatase activity was concluded that the toxic effects of herbicides in paddy field are usually severe immediately after application. Later on, soil enzyme activities are increased rapidly after three to five days of pre and post emergence application of herbicides. At 45 days after transplanting enzyme activities are shows similar or more compared with control and weedy check.