Plastic film mulching alleviates methane emissions in Asia: A meta-analysis

Soil methane (CH 4 ) cycling is critical to the global greenhouse gas budget, with arable soils functioning as both sources and sinks of this potent gas. Agricultural practices, particularly plastic film mulching (PFM), increasingly shape soil CH 4 emissions, yet the regulatory effects of PFM characteristics (e.g., film thickness, film coverage ratio and film type) and their interactions with environmental factors remain poorly understood. Here, we conducted a meta-analysis of Asian agroecosystems to quantify the responses of soil CH 4 emissions to PFM and identify the dominant controlling factors. Our results demonstrated that PFM mitigates soil CH 4 emissions in a characteristic-dependent manner. Specifically, a high film coverage ratio (≥ 50%) and thick films (≥ 0.01 mm) reduce CH 4 emissions significantly by 26.4% and 39.8%, respectively, whereas low film coverage ratio (< 50%) and thin films (< 0.01 mm) exert no significant effect. Film type mediates PFM efficacy, with black polyethylene films inducing greater CH 4 reduction relative to transparent films; in contrast, the mulching placement method (flat versus ridge-furrow) exhibits no significant impacts. Moreover, the CH 4 -mitigating effect of PFM is more pronounced under specific conditions: mean annual temperature (MAT) of 10–20°C, mean annual precipitation (MAP) > 800 mm, nitrogen application rates > 50 kg N ha −1 , and a humid climate (aridity index ≥ 0.65). Collectively, optimizing PFM practices can effectively mitigate CH 4 emissions in cropping systems when aligned with local conditions. This study provides a scientific basis for managing PFM to synergistically enhance agricultural sustainability and achieve climate mitigation goals.