High-Dose Biochar Hinders Micro/Nanoplastic-Induced Soil Positive Priming by Reducing Substrate Quality and Microbial Activity

作者：Xinghong Cao, Yalan Chen, Yakov Kuzyakov, Jie Chen, Yongxing Cui, Raúl Ochoa‐Hueso, Wenao Wu, Lichao Fan, Gao Qun, Shishu Zhu, Yunpeng Zhao, Siyuan Lu, Zhangliu Du, Lanfang Han, Biao Zhu, Fei Wang, Bo Gao, Ke Sun · 发表于：Environmental Science & Technology · 年份：2026 · DOI：10.1021/acs.est.5c11467 · 被引用次数：7 · 研究领域：Microplastics and Plastic Pollution、biodegradable polymer synthesis and properties、Additive Manufacturing and 3D Printing Technologies

Micro/nanoplastics are increasingly introduced into croplands via agricultural inputs such as mulching films and may accelerate soil organic carbon (SOC) turnover through priming effects. However, how long-term soil management practices influence these priming effects, and thus their implications for cropland carbon sequestration, remains unclear. Here, we conducted a 70-day incubation by adding polyethylene micro/nanoplastics at environmentally relevant concentrations (0.1, 0.5, and 1% w/w) to soils that had received biochar or straw amendments for 14 years. Using δ 13 C source partitioning, we found that micro/nanoplastics induced positive priming in control and low-dose biochar soils, driven by dilution from micro/nanoplastic-leached dissolved organic carbon (DOC), which increased bulk DOC and reduced aromaticity. These changes increased microbial biomass, C- and N-acquiring enzyme activities, intensifying nitrogen mining and SOC mineralization. Conversely, negative priming occurred in high-dose biochar soils and in straw-amended soils at the 0.1% micro/nanoplastic rate, where micro/nanoplastic addition reduced bulk DOC and increased aromaticity, likely via preferential sorption of low-aromatic soil DOC onto micro/nanoplastic surfaces. These changes reduced microbial biomass and enzyme activities while promoting the microbial preferential utilization of micro/nanoplastic-leached carbon, thereby favoring SOC preservation. Overall, this study demonstrates that high-dose bioc...