Aims Biodegradable film mulching (BFM) is a promising alternative to conventional plastic film mulching (PFM) for overcoming plastic pollution in dryland agriculture. However, its sustainability hinges on understanding its impact on soil nitrogen (N) supply for crop production and subsequent environmental consequences. Methods We conducted a field experiment with 15N tracing to quantify gross N transformation rates, complemented by measurements of N cycling functional genes, enzyme activities, plant N uptake and gas emissions. Results Our results demonstrated that BFM maintained maize yield and plant N uptake comparable to PFM, which is achieved by altering the soil N transformations. BFM stimulated dissimilatory NO3− reduction to NH4+ (DNRA) by 38%–56% throughout the maize growth stages and enhanced gross nitrification by 28% during the mid-to-late stages, thereby increasing soil NH4+ and NO3− availability. These changes in process rates were linked to an altered soil microbial community structure and an increased abundance of key functional genes (e.g., amoB, napA) under BFM. Although BFM decreased the N2O emissions by 0.3 kg N ha−1, it increased NH3 volatilization by 29% owing to higher NH4+ production. In rhizosphere soils, BFM also increased gross N mineralization and nitrification compared with PFM, indicated a high capacity for N supply for BFM. Structural equation modeling revealed that the film mulching type regulated gross N transformations primarily by altering microbial functions, which subsequently changed plant growth and N loss. Conclusions BFM enhances soil N supply and reduces N2O emissions by stimulating DNRA and nitrification, mediated by altered microbial communities and functions, but at the cost of increased NH3 volatilization. This study provides a mechanistic understanding of how BFM changes N cycling and N losses, offering a scientific basis for designing sustainable mulching systems in dryland agriculture. Graphical Abstract Concept of N transformations and fate in soil under conventional (PFM) and biodegradable film mulched (BFM) planting system describing the mechanisms of N supply and N loss. DNRA, the dissimilatory reduction rate of NO3− to NH4+.

How biodegradable mulching alters soil nitrogen transformations to enhance soil nitrogen supply and influence gas emissions in a maize cropping system

期刊论文
发表日期：

2026年2月6日

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Hao Zhang,
Kai Wang,
Jinbo Zhang,
Christoph Müller,
Dianyuan Ding,
Qiang Li,
Hengliang Tang,
Rui Jiang

摘要

Aims

Biodegradable film mulching (BFM) is a promising alternative to conventional plastic film mulching (PFM) for overcoming plastic pollution in dryland agriculture. However, its sustainability hinges on understanding its impact on soil nitrogen (N) supply for crop production and subsequent environmental consequences.

Methods

We conducted a field experiment with ¹⁵N tracing to quantify gross N transformation rates, complemented by measurements of N cycling functional genes, enzyme activities, plant N uptake and gas emissions.

Results

Our results demonstrated that BFM maintained maize yield and plant N uptake comparable to PFM, which is achieved by altering the soil N transformations. BFM stimulated dissimilatory NO₃⁻ reduction to NH₄⁺ (DNRA) by 38%–56% throughout the maize growth stages and enhanced gross nitrification by 28% during the mid-to-late stages, thereby increasing soil NH₄⁺ and NO₃⁻ availability. These changes in process rates were linked to an altered soil microbial community structure and an increased abundance of key functional genes (e.g., amoB, napA) under BFM. Although BFM decreased the N₂O emissions by 0.3 kg N ha⁻¹, it increased NH₃ volatilization by 29% owing to higher NH₄⁺ production. In rhizosphere soils, BFM also increased gross N mineralization and nitrification compared with PFM, indicated a high capacity for N supply for BFM. Structural equation modeling revealed that the film mulching type regulated gross N transformations primarily by altering microbial functions, which subsequently changed plant growth and N loss.

Conclusions

BFM enhances soil N supply and reduces N₂O emissions by stimulating DNRA and nitrification, mediated by altered microbial communities and functions, but at the cost of increased NH₃ volatilization. This study provides a mechanistic understanding of how BFM changes N cycling and N losses, offering a scientific basis for designing sustainable mulching systems in dryland agriculture.

Graphical Abstract

Concept of N transformations and fate in soil under conventional (PFM) and biodegradable film mulched (BFM) planting system describing the mechanisms of N supply and N loss. DNRA, the dissimilatory reduction rate of NO₃⁻ to NH₄⁺.