Distribution, Emission Sources, and Regional Disparities of Agricultural Carbon Emissions in China

Agricultural production is an important source of global carbon emissions, yet differences in system boundaries and emission factors among previous studies have limited comparisons across crops and regions. This study investigated the distribution, emission sources, and regional disparities of agricultural carbon emissions across 31 major crop-producing provinces in China, using a unified life cycle assessment (LCA) framework based on agricultural input, crop production, and agronomic data in 2024. Carbon emissions per unit area (CEA) and per unit yield (CEY) were quantified under consistent accounting boundaries, and the contributions of different emission sources together with their spatial characteristics were discussed. CEA generally showed higher values in the central and eastern regions of China and Xinjiang, but lower values in southwestern and northeastern China. Xinjiang contributed the highest total carbon emissions (about 1.6 × 105 t), primarily because extensive cotton cultivation requires intensive irrigation, mechanized operations, and plastic-film mulching, leading to high emissions from fertilizer use, energy consumption, and agricultural film. Rice exhibited the highest carbon emissions (accounting for 30% of all 11 types of crops), followed by cotton and tobacco, while soybeans, rapeseed, and sugar beets had relatively low emission intensities. Fertilizer production and application were the dominant emission sources for most upland crops, while methane emissions from flooded paddy fields accounted for the largest share of rice carbon emissions. Spatial clustering analysis further indicated that high-emission regions were concentrated in central and eastern China, while northeastern China formed distinct low-emission clusters. This study provided a consistent assessment of carbon emissions from major crops across China, offering a reference basis for formulating emission reduction strategies for different crops and regions.