Qiu Xinran, Ma Sirui, Liu Zhenyuan, Pan Jianrui, Ding Ling, Zhang Bin, Liang Xujun, Wang Peilei, Chen Tao, Guo Xuetao
College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China.
Key Laboratory of Plant Nutrition and the Agro-environment in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, China.
Environ Sci Technol. 2025 Jul 8;59(26):13385-13397. doi: 10.1021/acs.est.5c00875. Epub 2025 Jun 23.
Soil aggregate stability is vital for soil structure, erosion control, fertility, and crop productivity. Dissolved organic matter (DOM) turnover plays an important role in controlling the stability of soil aggregates, affecting aggregate formation and microbial activity. Microplastics (MPs) are known to impact soil DOM composition and structure, but their effects on DOM transformation in different soil aggregates remain unclear. Herein, we conducted 450 day incubation assays to study the effects of nondegradable and biodegradable MPs with varying aging levels on DOM transformations in agricultural soil aggregates. MPs were found to increase DOM transformation in soil aggregates, leading to changes in soil aggregate stability, including a reduction in geometric mean diameter and mass-weighted diameter. The addition of MPs resulted in a decrease in the stability of DOM in large-sized aggregates but an increase in the aromaticity and unsaturation of DOM in small-sized aggregates, which were more pronounced in the PLAMPs-treated group. This phenomenon is primarily attributed to the transformation of unsaturated aliphatic compounds and highly unsaturated and phenolic compounds, which play a major role in the intra- and intergroup transformation of DOM. In this process, microbial communities play a significant role. They tend to consume DOM in larger aggregates and produce DOM in smaller aggregates, leading to an accumulation of DOM in smaller aggregates, thereby promoting the formation of smaller aggregates and reducing the aggregate stability. This study uncovers the mechanisms of DOM transformation in response to MPs in soil aggregates, providing a scientific basis for soil management and sustainable agricultural development.
土壤团聚体稳定性对于土壤结构、侵蚀控制、肥力和作物生产力至关重要。溶解性有机物（DOM）周转在控制土壤团聚体稳定性、影响团聚体形成和微生物活性方面发挥着重要作用。已知微塑料（MPs）会影响土壤DOM的组成和结构，但其对不同土壤团聚体中DOM转化的影响仍不清楚。在此，我们进行了450天的培养试验，以研究不同老化水平的不可降解和可生物降解微塑料对农业土壤团聚体中DOM转化的影响。发现微塑料会增加土壤团聚体中DOM的转化，导致土壤团聚体稳定性发生变化，包括几何平均直径和质量加权直径减小。添加微塑料导致大尺寸团聚体中DOM稳定性降低，但小尺寸团聚体中DOM的芳香性和不饱和度增加，在PLAMPs处理组中更为明显。这种现象主要归因于不饱和脂肪族化合物以及高度不饱和和酚类化合物的转化，它们在DOM的组内和组间转化中起主要作用。在此过程中，微生物群落发挥着重要作用。它们倾向于消耗大团聚体中的DOM并在小团聚体中产生DOM，导致小团聚体中DOM积累，从而促进小团聚体形成并降低团聚体稳定性。本研究揭示了土壤团聚体中DOM响应微塑料的转化机制，为土壤管理和可持续农业发展提供了科学依据。
