Continuous cropping barriers lead to huge agriculture production losses, and fumigation and biological agents are developed to alleviate the barriers. However, there is a lack of literature on the differences between strong chemical fumigant treatment and moderate biological agent treatment. In this study, we investigated those differences and attempted to establish the links between soil properties, rhizosphere microbial community, and plant performance in both fumigation- and bioagent-treated fields. The results showed that the fumigation had a stronger effect on both soil functional microbes, i.e., ammonia oxidizers and soil-borne bacterial pathogens, and therefore, led to a significant change in soil properties, higher fertilizer efficiency, lower disease infections, and improved plant growth, compared with untreated control fields. Biological treatment caused less changes to soil properties, rhizosphere bacterial community, and plant physiology. Correlation and modeling analyses revealed that the bioagent effect was mainly direct, whereas fumigation resulted in indirect effects on alleviating cropping barriers. A possible explanation would be the reconstruction of the soil microbial community by the fumigation process, which would subsequently lead to changes in soil characteristics and plant performance, resulting in the effective alleviation of continuous cropping barriers.

Arsenic (As) is one of the most toxic metalloids that possess many forms. As is constantly migrating from abandoned mining area to the surrounding environment in both oxidation and reducing conditions, threatening human health and ecological safety. The biogeochemical reaction of As included oxidation, reduction, methylation, and demethylation, which is closely associated with microbial metabolisms. The study of the geochemical behavior of arsenic in mining areas and the microbial remediation of arsenic pollution have great potential and are hot spots for the prevention and remediation of arsenic pollution. In this study, we review the distribution and migration of arsenic in the mining area, focus on the geochemical cycle of arsenic under the action of microorganisms, and summarize the factors influencing the biogeochemical cycle of arsenic, and strategies for arsenic pollution in mining areas are also discussed. Finally, the problems of the risk control strategies and the future development direction are prospected.

Background and Aims Microbial diversity is a critical topic that concerns sustainable agriculture and crop production. Anthropogenic activities have a nonnegligible influence on both soil microbial diversity and crop production. Little research has been conducted to quantify the beneficial relationships between microbial diversity and soil productivity. Methods A meta-analysis based on 80 published papers was carried out to clarify the effects of anthropogenic activities including chemical fertilization (CF), organic fertilization (OF), intercropping or rotation (IC) and microbial treatment (MF), on soil microbial diversity and crop yield, and the relationship in between and summarized. Results The results showed that CF had the greatest potential for improving crop yield, whereas it may cause reductions in soil microbial diversity. OF is a sustainable development strategy, which increases both soil microbial diversity and crop yield. Under IC treatment, soil bacterial community diversity was significantly positively correlated with crop productivity, and the average effects of the four management approaches on soil microbial diversity and crop productivity were significantly different under different conditions. Conclusion Overall, our results have great guiding significance for ecological environment protection and crop economic benefits.