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Stabilization of acidification in China’s cropland soils

Nature Geoscience (2025)Cite this article

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Abstract

China’s cropland soil has faced acidification since the latter half of the twentieth century; however, the temporal and spatial variations of this are poorly known. Here we analyse cropland soil acidification using 7,024 regional surveys and a machine learning model to project spatiotemporal variations in cropland topsoil pH across China from 1985 to 2040. Our results reveal a turning point in China’s agricultural soil chemistry: consistent acidification from the 1980s ceased as a whole around 2013 (with a cumulative pH decline of ~0.25 units during 1985–2013), correlating strongly with changes in nitrogen fertilizer application patterns consequent to agricultural policy reforms. Regional heterogeneity was observed, with paddy fields exhibiting pH recovery post-2013 while values in dryland soils remained largely static since 2000. These findings underscore the critical role of agricultural policy and nitrogen fertilizer management in shaping soil health dynamics. This Article offers guidance for sustainable agriculture in China while providing insights applicable to global farming practices.

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Fig. 1: Chemical N fertilizer consumption and cropland soil pH trends.
Fig. 2: Trends in soil pH in paddy and dryland soils.
Fig. 3: Spatial distribution and temporal changes of soil pH in China’s cropland.
Fig. 4: Delineation of nine major agricultural zones and the trend of pH value of cropland soils (1985–2040).

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Data availability

All datasets analysed during this study are available in public repositories. Soil type, parent material and soil texture (sand, silt, and clay content) were acquired from the National Earth System Science Data Center (http://soil.geodata.cn and http://www.geodata.cn). Temperature, precipitation and PM10 data were sourced from the National Tibetan Plateau/Third Pole Environment Data Center (https://data.tpdc.ac.cn/home and https://doi.org/10.5281/zenodo.3752465). NHx-N and NOy-N deposition data were obtained from https://doi.org/10.1594/PANGAEA.942069 (ref. 55). Chemical N fertilizer consumption, rice yield, wheat yield and corn yield data originated from the China Statistical Yearbook (1981-2022), published by the National Bureau of Statistics of China (https://data.stats.gov.cn/publish.htm?sort=1). Land-use type data (https://geodata.pku.edu.cn/index.php?c=content&a=show&id=173) were derived from the China Multi-Period Land Use Land Cover Remote Sensing Monitoring Dataset (CNLUCC). The source data required to generate the figures in this study are available via figshare at https://doi.org/10.6084/m9.figshare.29108045.v2 (ref. 68). Data for the predictors can also be found in the Supplementary Information. Regional soil pH data are protected and are not available owing to data privacy laws.

Code availability

The codes for this study are available via Figshare at https://doi.org/10.6084/m9.figshare.29108045.v2 (ref. 68).

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Acknowledgements

We thank the many providers of data, which were an essential component of this work, and undergraduate students from NingboTech University and Yangtze University for collecting the data. We acknowledge the National Tibetan Plateau Data Center (TPDC) and the National Earth System Science Data Center (https://www.geodata.cn) for data support. This work is supported by the National Key Research and Development Program of China (nos. 2020YFC1807002 and 2021YFC1809103 to Y.Y., 2022YFD1700104 to Y. Luo and 2022YFD1900604 to J.L.) and the National Natural Science Foundation of China (nos. 42077140 to Y.Y., 41991335 to Y. Luo and 42177300 to J.L.).

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Author notes

  1. These authors contributed equally: Wangbo Zhang, Changlong Wei, Jiuyu Li, Qing Zhou.

Authors and Affiliations

  1. State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China

    Wangbo Zhang, Changlong Wei, Jiuyu Li, Qing Zhou, Yongming Luo & Yijun Yao

  2. University of Chinese Academy of Sciences, Beijing, China

    Wangbo Zhang, Jiuyu Li, Qing Zhou, Yongming Luo & Yijun Yao

  3. University of Chinese Academy of Sciences, Nanjing, China

    Wangbo Zhang, Jiuyu Li, Yongming Luo & Yijun Yao

  4. School of Civil Engineering and Architecture, NingboTech University, Ningbo, China

    Jianqing Ma

  5. Engineering Research Center of Ecology and Agricultural Use of Wetland, Ministry of Education/College of Agriculture, Yangtze University, Jingzhou, China

    Yanli Li, Yuxuan He & Yi Zou

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Contributions

Y.Y. conceived the idea. Y.Y. and Y. Luo designed the study. W.Z, Y. Li and Y.H collected the data. W.Z., C.W., J.L., J.M. and Y.Z. analysed the data. Y.Y., W.Z. and Q.Z. performed the modelling. Y.Y., W.Z., C.W., J.L. and Q.Z. wrote the first complete draft of the paper. Y.Y., W.Z. and Q.Z. revised the paper, with inputs from all co-authors. All authors contributed to the interpretation of results, writing and revision of the paper.

Corresponding authors

Correspondence to Yongming Luo or Yijun Yao.

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Nature Geoscience thanks the anonymous reviewer(s) for their contribution to the peer review of this work. Primary Handling Editors: Alison Hunt and Xujia Jiang, in collaboration with the Nature Geoscience team.

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Supplementary Figs. 1–15, Tables 1–3 and references.

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Zhang, W., Wei, C., Li, J. et al. Stabilization of acidification in China’s cropland soils. Nat. Geosci. (2025). https://doi.org/10.1038/s41561-025-01813-1

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