Table 5_Effects of different mulching practices on soil microbial community structure, function, and interaction networks in a chieh-qua cultivation.xlsx

Background and aimsMulching is a widely used agricultural management practice with profound effects on soil properties and crop productivity. However, its impact on soil microbial community structure and function remains insufficiently understood. This study aimed to investigate how different mulching treatments influence the composition, functional potential, and interaction networks of soil microbial communities in a chieh-qua–legume rotation system. MethodsMetagenomic sequencing was employed to analyze soil samples subjected to four mulching treatments (biodegradable mulch, non-degradable silver mulch, non-degradable black mulch, and straw mulch) as well as a no-mulch control (CK). ResultsMulching treatments significantly altered soil microbial diversity and community structure, with straw and biodegradable mulches supporting higher diversity than the control. Biodegradable mulch was strongly correlated with changes in soil pH and enriched denitrifying bacteria such as Thauera and Comamonadaceae, while reducing the abundance of genes related to energy metabolism and carbon fixation. These findings suggest that organic carbon from mulch degradation may enhance denitrification, potentially leading to nitrogen loss. Co-occurrence network analysis revealed that biodegradable mulch promoted more complex and connected microbial networks, whereas plastic mulches resulted in simpler structures. Additionally, all mulching treatments significantly reduced the abundance of the autotrophic ammonia-oxidizing archaeon Thaumarchaeota, likely due to reduced soil oxygen under mulch. ConclusionThis study provides new insights into how different mulching practices modulate soil microbial communities and their ecological functions. The results underscore the importance of tailoring mulching strategies to maintain soil health and fertility. Specifically, nitrogen supplementation is recommended when using biodegradable mulch in chieh-qua cultivation systems.背景与研究目的：覆盖栽培是一项广泛应用的农业管理措施，对土壤性状与作物生产力具有显著影响。然而其对土壤微生物群落结构与功能的影响仍有待深入阐明。本研究旨在探究不同覆盖处理对节瓜-豆科轮作体系中土壤微生物群落的组成、功能潜力及互作网络的影响。 研究方法：本研究采用宏基因组测序（Metagenomic Sequencing）技术，对4种覆盖处理（可降解地膜、非降解银色地膜、非降解黑色地膜、秸秆覆盖）及无覆盖对照组（CK）的土壤样品进行分析。 研究结果：覆盖处理显著改变了土壤微生物多样性与群落结构，其中秸秆覆盖与可降解地膜处理的微生物多样性显著高于对照组。可降解地膜处理与土壤pH变化呈显著相关，富集了陶厄氏菌属（Thauera）、丛毛单胞菌科（Comamonadaceae）等反硝化细菌，同时降低了与能量代谢及碳固定相关的基因丰度。该结果表明，覆盖物降解产生的有机碳可能强化反硝化作用，进而可能引发氮素流失。共现网络分析显示，可降解地膜处理促进了微生物网络形成更复杂且连通性更强的结构，而塑料地膜处理则导致网络结构更为简单。此外，所有覆盖处理均显著降低了自养氨氧化古菌——奇古菌门（Thaumarchaeota）的丰度，这可能与覆盖处理下土壤氧气含量降低有关。 研究结论：本研究为不同覆盖栽培措施如何调控土壤微生物群落及其生态功能提供了新的认识。研究结果强调了定制化覆盖策略对维持土壤健康与肥力的重要性。具体而言，在节瓜种植体系中使用可降解地膜时，建议补充氮素。