The effect of soil amendment with organic matter (Avena sativa on the proportions of 0, 7.5 and 15 g kg-1) on the toxicity of chlorothalonil fungicide (0, 12 and 48 µg of active ingredient per gram of soil) on the soil microflora was evaluated. The microbial biomass and the living hyphal length was measured at 11 and 26 days after application. Although the organic matter promotes a recuperation of the carbon of the microbial biomass, the oat doses used were not sufficient to inhibit completely the toxic effect of chlorothalonil. The results of living hyphal length demonstrated that it was not possible to recuperate the soil fungi population at the higher fungicide dose.
Avena sativa; microbial biomass; soil fungi population
