文摘
A three-month mesocosm experiment was performed to unravel interactions between pesticides (difenoconazole: fungicide, deltamethrin: insecticide, ethofumesate: herbicide) and fertilizers (NPK synthetic fertilizer, compost) regarding the potential non-target effects of pesticides on soil microbial communities. To this aim, pesticides and fertilizers were applied to soil at a rate of 5?mg active ingredient kg??DW?soil and 185?mg?N?kg? DW soil, respectively. Soil sampling was done after 0, 7, 30, 60 and 90 days of incubation in order to determine pesticide degradation rates and microbial properties: enzyme activities, basal respiration, substrate-induced respiration, potentially mineralizable N, nitrification rate and denitrification potential. By the end of the incubation, difenoconazole, deltamethrin and ethofumesate in non-fertilized soils were degraded by 52, 85 and 93 % , with half-lives of 86, 36 and 29 days, respectively. Compost application had a stimulatory effect on difenoconazole and deltamethrin degradation. NPK fertilization led to a 26 % increase in ethofumesate half-life in soil. Difenoconazole and deltamethrin caused a short-term inhibitory effect on microbial activity in non-fertilized soils, but not in fertilized soils. A short-term antagonistic effect between NPK fertilization and deltamethrin or ethofumesate presence was found regarding their inhibitory effect on potentially mineralizable N. In compost-fertilized soils, pesticides (especially, ethofumesate) counteracted the stimulatory effect of compost on denitrification potential. Pesticides caused a slight negative effect on the capacity of soils to recycle nutrients that was counteracted at day 90 by the addition of compost, as reflected by the values of the treated-soil quality index. We concluded that fertilizers can modify both pesticide degradation rates and their non-target effects on soil microbial communities.