Department of Agricultural Sciences, University of Naples Federico II, Naples, Italy.
Task Force On Microbiome Studies, University of Naples Federico II, Naples, Italy.
Microb Ecol. 2024 Jul 31;87(1):101. doi: 10.1007/s00248-024-02420-0.
Mulching is a common method increasing crop yield and achieving out-of-season production; nevertheless, their removal poses a significant environmental danger. In this scenario, the use of biodegradable plastic mulches comes up as a solution to increase the sustainability of this practice, as they can be tilled in soil without risk for the environment. In this context, it is important to study the microbial response to this practice, considering their direct involvement in plastic biodegradation. This study evaluated the biodegradation of three commercial mulch residues: one conventional non-biodegradable mulch versus two biodegradable ones (white and black compostable Mater-Bi mulches). The experiment was conducted under three incubation temperatures (room temperature 20-25 °C, 30 °C, and 45 °C) for a 6-month trial using fallow agricultural soil. Soil without plastic mulch residues was used as a control. White mater-bi biodegradable mulch residues showed higher degradation rates up to 88.90% at 30 °C, and up to 69.15% at room temperature. Furthermore, incubation at 45 °C determines the absence of degradation for all types of mulch considered. Moreover, bacterial alpha diversity was primarily influenced by plastic type and temperature, while fungal populations were mainly affected by temperature. Beta diversity was impacted by all experimental variables. Predicted functional genes crucial for degrading complex substrates, including those encoding hydrolases, cutinases, cellobiosidases, and lipases, were derived from 16S rRNA gene sequencing data. Cluster analysis based on predicted enzyme-encoding gene abundance revealed two clusters, mainly linked to sampling time. Finally, core microbiome analysis identified dominant bacterial and fungal taxa in various soil-plastic ecosystems during degradation, pinpointing species potentially involved in plastic breakdown. The present study allows an assessment of how different temperatures affect the degradation of mulch residues in soil, providing important insights for different climatic growing zones. It also fills a gap in the literature by directly comparing the effects of biodegradable and polyethylene mulches on soil microbial communities.
覆盖是一种常见的提高作物产量和实现反季节生产的方法；然而，它们的去除对环境构成了重大威胁。在这种情况下，使用可生物降解塑料覆盖物成为提高这种做法可持续性的一种解决方案，因为它们可以在没有环境风险的情况下被翻耕到土壤中。在这种情况下，研究微生物对这种做法的反应很重要，因为它们直接参与塑料的生物降解。本研究评估了三种商业覆盖物残留物的生物降解性：一种传统的不可生物降解的覆盖物与两种可生物降解的覆盖物（白色和黑色可堆肥 Mater-Bi 覆盖物）进行了对比。实验在三种培养温度（室温 20-25°C、30°C 和 45°C）下进行，为期 6 个月，使用休耕地农业土壤。没有塑料覆盖物残留物的土壤用作对照。白色 Mater-Bi 可生物降解覆盖物残留物在 30°C 时表现出高达 88.90%的更高降解率，在室温下达到 69.15%。此外，在 45°C 下培养确定了所有考虑的覆盖物都不存在降解。此外，细菌的 alpha 多样性主要受塑料类型和温度的影响，而真菌种群主要受温度的影响。β多样性受到所有实验变量的影响。从 16S rRNA 基因测序数据中得出了对降解复杂基质至关重要的预测功能基因，包括编码水解酶、角质酶、纤维二糖酶和脂肪酶的基因。基于预测酶编码基因丰度的聚类分析显示了两个主要与采样时间相关的聚类。最后，核心微生物组分析确定了在降解过程中不同土壤-塑料生态系统中占优势的细菌和真菌类群，确定了可能参与塑料分解的物种。本研究评估了不同温度如何影响土壤中覆盖物残留物的降解，为不同气候生长带提供了重要的见解。它还通过直接比较可生物降解和聚乙烯覆盖物对土壤微生物群落的影响，填补了文献中的空白。
