Effect of propiconazole on substrate amended soil respiration following laboratory and field application

Abstract

AbstractThe effect of the fungicide propiconazole (‘Tilt’TM 250 EC) on substrate‐amended soil respiration has been studied in dose‐response experiments, following application of the compound in the field and in the laboratory. The field study was supplemented with spray‐deposition measurements showing a throughfall at the soil surface of 15‐45%, depending on the time of fungicide application. When propiconazole was amended to the soil in low dosages in laboratory conditions, the soil respiration was stimulated. Even at the very high and agriculturally unrealistic dosages in the laboratory experiment, the mean, daily soil respiration almost recovered within the incubation period of 30 days. Given the present conditions, the results did, however, also show that side‐effects of the application of the fungicide were provoked at lower dosages in the field, and that they lasted for a considerably longer time than in the laboratory, indicating the importance of indirect effects of fungicide application in field conditions. Possible reasons for the dose‐response relationship in the field being different from the one found in the laboratory are discussed.