Low-dose polylactic acid microplastics mitigate methane emissions in ratoon rice systems
Abstract
Biodegradable plastics are increasingly introduced into agricultural systems, yet their ecosystem-scale climate impacts on methane (CH₄) emissions remain poorly understood. Here, we evaluated the effects of environmentally realistic, low-dose polylactic acid (PLA) microplastics on CH₄ emissions and food safety across a full ratoon rice growing cycle. PLA amendment reduced cumulative methane (CH₄) emissions by 36.4% (8.42 ± 0.54 vs. 5.35 ± 0.27 g m⁻²) without affecting CO₂ exchange, crop productivity, or grain metal(loid) concentrations. Temporal analyses revealed that CH₄ dynamics were primarily governed by crop phenology. Process-based modeling evidence indicated that PLA induced persistent soil redox regulation, suppressing methanogenesis while avoiding the typical trade-off between CH₄ mitigations and heavy-metal risks. Moreover, PLA reduced the apparent temperature sensitivity of CH₄ emissions, suggesting enhanced system stability under heat extremes. These findings identify a previously overlooked pathway linking biodegradable material inputs with ecosystem CH₄ regulation and highlight their potential contribution to carbon-neutral agricultural management.
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Declaration of Competing Interests
The authors declare no competing interests to disclose.
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