Work

Lower Direct N2O Emission Factors in Chinese Croplands than IPCC Defaults: A Systematic Meta-Analysis

Year: 2026

Type: article

Study designs: Systematic Review, Meta-Analysis

Abstract: Nitrous oxide (N2O) is a major agricultural greenhouse gas. Its direct emission factor (EF) is a key parameter for greenhouse gas inventories and developing mitigation strategies. However, the Intergovernmental Panel on Climate Change (IPCC) default EF may not reflect actual emissions from Chinese croplands. This study compiled extensive field observations from key agricultural regions in China. A systematic meta-analysis was conducted to evaluate annual N2O emissions and nitrogen fertilizer-induced direct emission factors. Subgroup analyses revealed that fertilizer type, land use, soil texture, and climate zone all significantly influence EF. Univariate meta-regression indicated that EF is positively correlated with nitrogen (N) application rate and mean annual temperature but negatively correlated with soil pH, highlighting these factors as key drivers of N2O emissions. The mean EF in Chinese croplands was about 0.68%, much lower than the 1% global default recommended by the IPCC. The combined effects of optimized agricultural management, cropping systems, and local environmental conditions help explain these lower emission factors. These findings provide a scientific basis for developing region-specific emission factors, improving cropland mitigation strategies, and enhancing the accuracy of greenhouse gas inventories.

Source: Atmosphere

DOI: 10.3390/atmos17040422

Authors: Ke Xu, Duo Xu, Pinrong Ji, Caiqing Qin

Institutions: Xi'an Jiaotong University, Hohai University

Language: English

Topic: Soil Carbon and Nitrogen Dynamics

Subfield: Soil Science

Field: Agricultural and Biological Sciences

Domain: Life Sciences

SDGs: Climate action, Zero hunger

Open Access status: gold

Estimated APC paid: $2,896