熏蒸剂对土传病原菌的防效和对土壤微生物群落的影响

Efficacies of Fumigants Against Soil-borne Pathogens and Their Influences on Soil Microbial Community

为了明确熏蒸剂对2种土传病原菌的持续防效以及对土壤微生物群落的恢复影响,采用选择性培养基分离计数、土壤微生物量碳、土壤微生物量氮和BIOLOG的方法研究氯化苦(chloropicrin,PIC)40 mg/kg、二甲基二硫(dimethyl disulfide,DMDS)40 mg/kg以及PIC+DMDS(8+32)mg/kg对镰孢菌属(Fusarium spp.)、疫霉菌属(Phytophthora spp.)的长期抑制效果,以及对土壤微生物群落的影响。结果表明,恢复培养98天时,PIC 40 mg/kg对镰孢菌属和疫霉菌属仍然有很好的抑制作用,抑制率分别维持在98%、55%以上,而该处理对土壤微生物的影响已恢复到对照水平。与DMDS(40 mg/kg)相比,PIC+DMDS[(8+32)mg/kg]处理对镰孢菌属和疫霉菌属的持续抑制作用都有很大提高。在恢复培养28天时,PIC+DMDS[(8+32)mg/kg]处理对土壤微生物群落多样性的影响已恢复到对照水平。DMDS(40 mg/kg)处理对镰孢菌属和疫霉菌属的抑制效果较差,但该处理对土壤微生物量和土壤微生物群落影响也相应较小。

In order to investigate the long term efficacies of fumigants on two soil-borne pathogens and their influences on soil microbial community recovery, the authors studied the efficacies of ehloropicrin （PIC） 40 mg/kg, dimethyl disulfide （DMDS） 40 mg/kg and PIC ＋ DMDS （8 ＋ 32） 40 mg/kg on Fusarium spp. and Pbytophthora spp., as well as their influences on soil microbial community by using plate count, soil microbial biomass carbon, soil microbial biomass nitrogen and BIOLOG method. The results indicated that after 98 days fumigation, chloropicrin （PIC） 40 mg/kg still had significant efficacies in controlling Fusarium spp. and Phytophthora spp., while its influences dimethyl disulfide （DMDS） （8＋32） mg/kg on soil microbial community had recovered to control level. PIC ＋ was more effective in long term Fusarium spp. and Phytophtbora spp. suppression compared with DMDS 40 mg/kg. 28 days after fumigation, influence of PIC＋DMDS （8＋32） mg/kg on soil microbial community diversity had recovered to control level. In line with its lower efficacies against soil-borne pathogens, DMDS 40 mg/kg had little influence on soil microbial biomass and soil microbial community diversity.