EFFECT OF HEXACHLOROCYCLOHEXANE ON METHANE PRODUCTION AND EMISSION FROM FLOODED RICE SOIL

Application of commercial formulation (an isomeric mixture) of hexachl orocyclohexane (HCH) to flooded rice fields planted to cv. Rasi at 1 k g active ingredient.ha(-1) significantly inhibited methane emission. N egative relationship existed between methane emission from HCH-treated fields and root oxidase activity (in terms of alpha-naphthylamine oxi dised). Under laboratory conditions, the addition of technical grade a lpha-, beta-, gamma- and delta-isomers (99.1% purity) of HCH, individu ally at 20 mu g.g(-1) soil at flooding, effected a distinct inhibition of methane production. Evidence suggests that the inhibitory effect o f all the four isomers on methane production only until 20-25 days aft er their application was related to their persistence in flooded soil. (C) 1997 Elsevier Science Ltd.