[Response Characteristics of Soil Microbial Community Under Long-term Film Mulching].

Film mulching is an important practice to increase the yield and income in agricultural production. Soil samples were collected from four farmland sites with different mulching years to reveal the effect of long-term plastic mulching on characteristics of soil microbial community structure. In order to explore the long-term effect of soil microbial community change and its effect on the microbial ecological environment, high-throughput sequencing technology was used to analyze the changes in soil bacterial and fungal community structure. The results showed that long-term film mulching had no significant effect on soil bacterial diversity but decreased fungal diversity. Long-term film mulching decreased the abundance of Acidobacteriota and Mortierellomycetes and increased the abundance of Actinobacteriota. Long-term film mulching enriched the beneficial microbial communities such as Bacillus, Nocardioidaceae, Aspergillus, and Hypocreales in soil. However, long-term film mulching indued a simple and fragile soil fungal co-occurrence network pattern. The unidentified Sordariales under Ascomycota was the only key species in the fungal co-occurrence network, which resulted in potential risks to the ecological environment of the farmland soil. This study provided a theoretical basis for further understanding the effects of long-term film mulching on the ecological and environmental effects of microorganisms in farmland.

Microplastics shape microbial communities affecting soil organic matter decomposition in paddy soil.

Microplastics (MPs) can alter microbial communities and carbon (C) cycling in agricultural soils. However, the mechanism by which MPs affect the decomposition of microbe-driven soil organic matter remains unknown. We investigated the bacterial community succession and temporal turnover during soil organic matter decomposition in MP-amended paddy soils (none, low [0.01% w/w], or high [1% w/w]). We observed that MPs reduced the CO2 efflux rate on day 3 and subsequently promoted it on day 15 of incubation. This increased CO2 emission in MP-amended soil may be related to (i) enhanced hydrolase enzyme activities or; (ii) shifts in the Shannon diversity, positive group interactions, and temporal turnover rates (from 0.018 to 0.040). CO2 efflux was positively correlated (r > 0.8, p < 0.01) with Ruminiclostridium_1, Mobilitalea, Eubacterium xylanophilum, Sporomusa, Anaerobacteriu, Papillibacter, Syntrophomonadaceae, and Ruminococcaceae_UCG_013 abundance in soil with high MPs, indicating that these genera play important roles in soil organic C mineralization. These results demonstrate how microorganisms adapt to MPs and thus influence the C cycle in MP-polluted paddy ecosystems.