Degradation of sulcotrione in a brown soil amended with various organic matters

We investigated sulcotrione degradation in a sandy-silty brown soil. The agricultural field was divided into three small plots ten years ago, named plots R for reference, M for manure and CM for compost manure. The degradation experiment was conducted under controlled laboratory conditions using C-14 benzene uniformly ring-labelled sulcotrione. In the first month of the experiment, 80% of the residues was extractable with solvent, 55% of sulcotrione was degraded, including 45% into 2-chloro-4-methylsulfonylbenzoic acid (CMBA), the most abundant metabolite of sulcotrione. 10% of the residues was mineralised. After two months, 40% of the residues was extractable, including 16% of sulcotrione, 25% was mineralised and 35% formed non-extractable residues. Soil amended with different organic matters favoured transformation of sulcotrione in soil. The fresh manure amendment activated mineralisation of 10%, and the compost manure amendment induced a lower ratio of extractable sulcotrione at a level of 5%.