多菌灵重复施药对其持久性及土壤微生物群落功能多样性的影响

选择浙江大学华家池校区大棚蔬菜试验田,研究了多菌灵(以active ingredient,a.i.计)0.94、1.88和4.70 kg hm-2三种剂量重复施药对其持久性及土壤微生物功能多样性的影响。结果表明,第1次施药后,多菌灵在土壤中的降解速率分别为0.11、0.25、0.74 mg kg-1d-1;第4次施药后,多菌灵在土壤中的降解速率分别达到0.18、0.39、1.00 mg kg-1d-1。随着施药次数的增加,多菌灵的降解速率逐渐增大。初次施药后,土壤微生物群落AWCD值明显低于对照,土壤微生物群落的Shannon、Simpson和McIntosh指数也均低于对照水平。第4次施药后,三个处理土壤微生物群落的AWCD值、Shannon、Simpson和McIntosh指数均恢复到对照水平。

Effects of repeated application of carbendazim on its persistence and diversity of soil microbial community under field conditions

Effects of repeated application of fungicide carbendazim at a rate of 0.94, 1.88, 4.70 kg hm^-2 calculated by active ingredient (a.i.) on diversity of soil microbial communities were studied using BIOLOG and its degradation dynamics in soil was investigated under field conditions. The degradation rate of carbendazim after the first application in the soil was 0.11, 0.25 and 0.74 mg kg^-1d^-1, in treatments of 0.94, 1.88 and 4.70 kg hm^-2 calculated by a.i., respectively, and rose to 0.8, 0.39 and 1.00 mg kg^-1d^-1, respectively after the fourth application, showing a significant trend of the degradation rate rising with the application frequency. A significant inhibitory effect of carbendazim on average well color development (AWCD) was observed after the first application. The AWCD values then increased slightly with the application frequency Shannon, Simpson and Shannon indexes of the soil microbial communities in the soil were also inhibited by the first application, which suggested that the richness, evenness and dominant character of soil communities in the treated soils were altered by the repeated application of carbendazim. However, after the second application, soil microorganisms gradually adapted to carbendazim and recovered to the level in the control without carbendazim treatment.