A STUDY ON THE MINERALIZATION OF C-14 ACIFLUORFEN IN SOIL - COMPARISON BETWEEN TREATED AND UNTREATED SOILS

The mineralisation of C-14 acifluorfen was assessed in a soil previous ly treated with the herbicide and in a control soil, in various incuba tion conditions. Although the amount of (CO2)-C-14 produced was very l ow both in treated and untreated soils indicating that the herbicide i s not easily mineralized, the mineralization rate was higher in the pr eviously treated soil than in the untreated one suggesting a selection performed by the herbicide on the degrading microbial population. Suc h an hypothesis seems to be confirmed by the lower degradation observe d in fumigated than in non fumigated soils and by the enhancement of m ineralization due to the addition of degrading mixed bacterial populat ions. The addition of 2-nitrobenzoic acid, whose chemical structure is analogous to AC reduced the mineralization, probably because of conju gated compounds formation.