Polyethylene microplastics hamper aged biochar’s potential in mitigating greenhouse gas emissions

作者：Yalan Chen, Zhibo Wang, Anqi Zhang, Lijun Yang, Ke Sun, Chenrun Jiang, Anna Gunina, Abeer S. Aloufi, Xinru Liang, Zichen Han, Yue Xiao, Yunqian Zhang, Zhangliu Du, Shishu Zhu, Yakov Kuzyakov · 发表于：Carbon Research · 年份：2025 · DOI：10.1007/s44246-024-00170-9 · 被引用次数：5 · 研究领域：Microplastics and Plastic Pollution、biodegradable polymer synthesis and properties、Recycling and Waste Management Techniques

Abstract While biochar effectively reduces greenhouse gas emissions, the coincident microplastics will alter these benefits. To assess the long-term efficacy of biochar application in reducing emissions amidst microplastic interference, we investigated the interactive effects of polyethylene microplastics (1%–5% wt) and decadal biochar addition (aged biochar) on C and N stability in a Fluvic Cambisol. Aged biochar and polyethylene individually reduced CO 2 emissions by 49% and 18%, respectively, over 91-day incubation. This was due to decreased soil aggregation, dissolved organic matter (DOM) content, and increased DOM aromaticity, which reduced microbial biomass and chitinase activity associated with soil organic matter (SOM) decomposition. This ultimately led to increased accumulation of microbial necromass carbon (MNC) to soil stable carbon pool. Interestingly, the coexistence of polyethylene diminished the efficacy of biochar in mitigating CO 2 emissions (+ 44 ~ 82%) and stabilizing MNC (-18 ~ 23%). This was because the interaction between polyethylene and biochar facilitated macroaggregate formation and DOM accumulation and decreased DOM aromaticity, which increased microbial biomass and chitinase activity for SOM decomposition. Similar to soil C dynamics, aged biochar largely reduced N 2 O emissions by 54%, due to decreased nirK but increased nifH genes. Polyethylene increased N 2 O emissions by 5% and 25% in biochar-free and aged biochar soil, respectively, likely thro...