ORIGINAL RESEARCH article
Front. Plant Sci.
Sec. Plant Nutrition
Partial substitution of nitrogen fertilizer by Chinese milk vetch with different improvement measures achieves a win-win for rice productivity and environmental benefits
Provisionally accepted
- 1Anhui Agricultural University, Hefei, China
- 2Soil and Fertilizer Institute, Anhui Academy of Agricultural Science, Hefei, China
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Introduction: Green manuring has been proven to be a sustainable strategy for enhancing paddy soil fertility and reducing chemical fertilizer input. However, the anaerobic decomposition of green manure in flooded soils leads to substantial increase in methane (CH4) emissions. This study explored the coordinative effects of optimized water management and introduced emission reduction material on greenhouse gas (GHG) emissions in a Chinese milk vetch-rice rotation system. Methods: A two-year (2022–2024) field experiment was conducted with four treatments: (T1, control) winter fallow + conventional nitrogen application; (T2) green manuring + 30% nitrogen reduction; (T3) green manuring + 30% nitrogen reduction + delayed flooding; and (T4) green manuring + 30% nitrogen reduction + ethephon application. Compared to T1, T2 treatment maintained rice yields while having no significant effect on annual cumulative CH4 emissions from the paddy field system. The global warming potential (GWP) slightly decreased under T2 treatment due to reduced nitrous oxide (N2O) emissions. T3 treatment lowered CH4 emissions in the stage between green manuring and rice transplanting (–80.2%), leading to noticeable reductions in annual GWP (–17.6%) and GHG intensity (–23.7%). Under T4 treatment, CH4 emissions were suppressed after green manuring until rice harvest (–33.6%), accounting for the lowest annual GWP (–29.9%) and GHG intensity (–37.1%) alongside the highest rice yields. All improvement measures reduced the carbon footprint and enhanced the net ecosystem economic benefit, with T4 treatment demonstrating the maximum economic and environmental benefits. Conclusion: When applying Chinese milk vetch to substitute 30% of nitrogen fertilizer in the rice season, integration with delayed flooding or ethephon application leads to coordinated rice yield improvement and GHG emission reduction. This study provides a feasible agronomic strategy for green production in paddy fields and offers a technical solution for mitigating GHG emissions while safeguarding rice productivity.
Keywords: Carbon Footprint, emission reduction material, Green manure, Net ecosystem economic benefit, nitrogen fertilizer, Water Management
Received: 08 Dec 2025; Accepted: 13 Feb 2026.
Copyright: © 2026 Han, Bu, Zhou, Tang, Wang, Li, Cheng, Wu and Gao. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Ji Wu
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