Effects Of Fungicide Fluopyram On Soil Microbial Community Diversity

Fluopyram a pyridinylethyl benzamide fungicide developed for more than70crops (including vines and table grapes, pome and stone fruits, vegetables and field crops), which mainly consists of the inhibition of succinate dehydrogenase. It will result in potential environmental contamination. The mechanism of fluopyram affecting soil microbial were investigated by detected the residue of fluopyram in soil and the effected of fluopyram on soil basal respiration, potential respiration, MBC, functional diversity and structure diversity.1. A rapid, sensitive and environmental-friendly method has been developed for analysis the residue of fluopyram in soil. To detect the residue of fluopyram, the UPLC-MS/MS in the multiple-reaction monitoring mode was used. m/z397.3>208and m/z397.3>173were chosen to identify and quantify fluopyram, respectively. In soil samples, average recoveries of fluopyram were in the range from80.2to84.0%at three spiking levels of0.01mg/kg,0.5mg/kg and5mg/kg. The relative standard deviations were between2.45%and7.88%. Limit of quantification of fluopyram was0.13μg/kg.2. The effects of fluopyram on soil microbial were studied by culture experiments in laboratory. In the experiments, the soil had been subjected to conventional-tillage and not treated with fluopyram. Four treatments were assigned, including no fluopyram control, the biggest recommended field dosage (75g ai/ha0.5mg/kg),3times of the biggest recommended field rate (1.5mg/kg) and10times of the biggest recommended field rate (5mg/kg). Samples were collected at random from each tray at different time intervals,7,15,30,45,60,90days after application of fluopyam. The collected soils were determinated the residue of fluopyam, soil respiration, soil microbial biomass C, functional diversity using BIOLOG Ecoplates and structure diversity by PLFA.The fluopyam degradated in soil described by a first order kinetics model. The half-time of fluopyam in soil was ranged from64.2day to93.6day. During the experiment time, three kinds of fluopyam enhanced the respiration intensity of soil. But the microbial biomass C of the soil applied with different dose of fluopyam was much lower than the blank soil. The values of metabolic quotient are higher than the blank soil.The values of AWCD in T1were significantly (P<0.05) higher than control at first30day and recovered at day45, but the values of AWCD in T3and T10were significantly (P<0.05) lower than control during the incubation period. The values of Shannon index in T1, T3and T10were lower than control at first15day and recovered at day30. The result of Simpson index in T1, T3and T10were in line with AWCD. The values of McIntosh index in T1have no significant effect during the incubation period, but McIntosh index in T3and T10were significantly (P<0.05) lower than control during the incubation period. The values of total PLFA, GN/GP and Fungi/Bacteria were significantly (P<0.05) lower than control during the incubation period. The result of PCA on the Biolog and PLFAs showed that the microbial community functional diversity and structure diversity of of the soil applied with different dose of fluopyam were differed from blank soils.