Abstract：
Pre-plant soil fumigation is widely applied to control nematodes, soil-borne fungal pathogens, and weeds in vegetable crops. However, most of the research evaluating the effect of fumigants on crop yield and soil microbial communities has been done on single compounds despite growers mainly applying fumigant combinations. We studied the effect of different fumigant combinations (chloropicrin, 1,3-dichloropropene, and metam potassium) on soil properties, crop yield, and the soil bacterial and fungal microbiome for two consecutive years in a plastic-mulched tomato production system in Florida (United States). While combinations of fumigants did not improve plant productivity more than the individual application of these products, application of fumigants with >60 % chloropicrin did significantly increase yield. Fumigant combinations had no significant effect on bacterial diversity, but fumigants with >35 % chloropicrin reduced soil fungal diversity and induced temporary changes in the soil bacterial and fungal community composition. These changes included short-term increases in the relative abundance of Firmicutes and Ascomycota, as well as decreases in other bacterial and fungal taxa. Repeated fumigation reduced network complexity and the relative abundance of several predicted bacterial functions and fungal guilds, particularly after fumigation and at end of harvest (3-months post fumigation). A structural equation model (SEM) showed fumigants not only directly impact crop yield, but they can also indirectly determine variations in plant productivity through effects on the soil microbiome. Overall, this study increases our understanding of the environmental and agricultural impacts of fumigants in a plastic-mulched tomato production system.
摘要：
种植前土壤熏蒸被广泛应用于线虫的防治,土传真菌病原体，和蔬菜作物中的杂草。然而,尽管种植者主要使用熏蒸剂组合，但大多数评估熏蒸剂对作物产量和土壤微生物群落的影响的研究都是对单一化合物进行的。我们研究了不同熏蒸剂组合(氯化苦，1,3-二氯丙烯,和镁钾)对土壤性质的影响，作物产量，以及在佛罗里达州（美国）的塑料覆盖番茄生产系统中连续两年的土壤细菌和真菌微生物组。虽然熏蒸剂的组合没有比这些产品的单独应用更能提高植物生产力，使用>60％氯化苦的熏蒸剂确实显着提高了产量。熏蒸组合对细菌多样性没有显著影响，但含>35%氯化苦的熏蒸剂会降低土壤真菌多样性，并引起土壤细菌和真菌群落组成的暂时变化。这些变化包括Firmicutes和Ascomycota相对丰度的短期增加，以及其他细菌和真菌类群的减少。反复熏蒸降低了网络的复杂性和几种预测的细菌功能和真菌协会的相对丰度，特别是在熏蒸后和收获结束时（熏蒸后3个月）。结构方程模型(SEM)表明，熏蒸剂不仅直接影响作物产量，但它们也可以通过对土壤微生物组的影响间接决定植物生产力的变化。总的来说,这项研究增加了我们对熏蒸剂在塑料覆盖的番茄生产系统中的环境和农业影响的理解。
