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Acta Prataculturae Sinica ›› 2025, Vol. 34 ›› Issue (2): 196-210.DOI: 10.11686/cyxb2024111

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Techniques of N2O emission reduction in farmland and their synergistic application with green manure

Rui LIU1(), Dan-na CHANG2, Guo-peng ZHOU3, Song-juan GAO4, Qiang CHAI1(), Wei-dong CAO2()   

  1. 1.State Key Laboratory of Arid Land Crop Science,College of Agronomy,Gansu Agricultural University,Lanzhou 730070,China
    2.State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China,Institute of Agricultural Resources and Regional Planning,Chinese Academy of Agricultural Sciences,Beijing 100081,China
    3.Anhui Province Key Laboratory of Farmland Ecological Conservation and Pollution Prevention,College of Resources and Environment,Anhui Agricultural University,Hefei 230036,China
    4.College of Resources and Environmental Sciences,Nanjing Agricultural University,Nanjing 210095,China
  • Received:2024-04-09 Revised:2024-06-17 Online:2025-02-20 Published:2024-11-27
  • Contact: Qiang CHAI,Wei-dong CAO

Abstract:

Nitrous oxide (N2O) is one of four the main gases linked to global warming, and agricultural production is the largest anthropogenic source of N2O emissions. N2O mainly originates from nitrification and denitrification processes in soil and is predominantly influenced by soil pH value, O2 concentration, CO2 concentration, moisture, texture, temperature, and exogenous carbon (C) and nitrogen (N) input. In recent years, China has achieved remarkable results in using green manure to reduce chemical N fertilizer application and drive soil health. However, study of the role of green manure in N2O emission is still in the early stages. The impact of planting and incorporating green manure on soil N2O emission depends on factors such as the varieties of green manure and the physicochemical properties of the soil. Among them, the influence on soil mineral N is the greatest factor. Generally, green manure can efficiently absorb soil mineral N in the fallow period, and its incorporation into the soil can reduce chemical N fertilizer application, thus decreasing N2O emission. However, green manure releases large amounts of N during its decomposition, which may increase soil N2O emissions. Combined with appropriate N2O emission reduction approaches, N2O emission in green manure-based systems can be reduced according to planting systems, crop varieties, climate conditions and soil types. In southern China’s rice-green manure rotation area, chemical N could be reduced by 40%, when adding alkaline amendments such as biochar. In northern China’s main crop-green manure rotation area, chemical N could be reduced by 15%-20%, through adding chemical inhibitors and combining mechanical deep application of chemical N fertilizers. For main crops rotated or intercropped with green manure systems in Northeast and Northwest China, chemical N could be reduced by 13%-48%, by adding nitrification inhibitors, with integrated water-fertilizer management practices and no-tillage. In main crops rotated with green manure systems of Southwest China, chemical N could be reduced by 15%-20%, through techniques such as slow-release fertilization, use of chemical inhibitors, and others. In this study we have focused on the feasibility of N2O emission reduction by combining green manure practices and exogenous reduction approaches to N2O emission, to provide practical guidance for reducing N2O emission in green manure-based systems.

Key words: green manure, nitrous oxide, influencing factors, emission reduction technology