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

TY - JOUR

T1 - High-Dose Biochar Hinders Micro/Nanoplastic-Induced Soil Positive Priming by Reducing Substrate Quality and Microbial Activity

AU - Cao, Xinghong

AU - Chen, Yalan

AU - Kuzyakov, Yakov

AU - Chen, Ji

AU - Cui, Yongxing

AU - Ochoa-Hueso, Raúl

AU - Wu, Wenao

AU - Fan, Lichao

AU - Gao, Qun

AU - Zhu, Shishu

AU - Zhao, Yunpeng

AU - Lu, Siyuan

AU - Du, Zhangliu

AU - Han, Lanfang

AU - Zhu, Biao

AU - Wang, Fei

AU - Gao, Bo

AU - Sun, Ke

N1 - Data archiving: no NIOO data

PY - 2026/1/23

Y1 - 2026/1/23

N2 - 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 δ13C 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 biochar hinders micro/nanoplastic-induced positive priming by regulating substrate–microbial interactions, with important implications for cropland carbon retention.

AB - 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 δ13C 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 biochar hinders micro/nanoplastic-induced positive priming by regulating substrate–microbial interactions, with important implications for cropland carbon retention.

KW - biochar amendment

KW - dissolved organic carbon

KW - micro/nanoplastics

KW - priming effect

KW - δC source partitioning

U2 - 10.1021/acs.est.5c11467

DO - 10.1021/acs.est.5c11467

M3 - Article

C2 - 41575252

AN - SCOPUS:105029378633

SN - 0013-936X

VL - 60

SP - 3475

EP - 3485

JO - Environmental Science and Technology

JF - Environmental Science and Technology

IS - 4

ER -