Zhang et al. (2025) Spatiotemporal dynamics of crop water use and groundwater depletion under the winter wheat–summer maize rotation system in Henan Province, China

Identification

• Journal: Frontiers in Plant Science
• Year: 2025
• Date: 2025-12-11
• Authors: Zhao Zhang, Jing Wang, Jing Ning, Jinsong Ti
• DOI: 10.3389/fpls.2025.1728535

Research Groups

College of Tobacco Science, Henan Agricultural University, Zhengzhou, China

Short Summary

This study quantified the spatiotemporal dynamics of crop water use and groundwater depletion in Henan Province (1961-2020) under a winter wheat–summer maize rotation, revealing that while winter wheat is the primary driver of depletion, summer maize's groundwater use has sharply increased since 2010, intensifying water stress in the central–northern plains.

Objective

• To quantify the long-term spatiotemporal patterns of crop evapotranspiration (ETc), effective precipitation (Re), and irrigation water requirement (Iwr) for winter wheat and summer maize under the rotation system.
• To estimate stage-based and decadal net groundwater consumption (NGWC) and annual net groundwater consumption (ANGWC) for both crops, and to reveal how groundwater depletion has evolved across space and time.
• To assess the implications of alternative cropping and irrigation strategies, including winter wheat fallowing and summer maize water conservation, for relieving groundwater stress and supporting sustainable agricultural water management in this major grain-producing region.

Study Configuration

• Spatial Scale: Henan Province, China, covering 18 prefecture-level cities, with analysis conducted at the county level.
• Temporal Scale: 1961 to 2020 (60 years), with decadal mean calculations for annual net groundwater consumption.

Methodology and Data

• Models used:
  • Water balance framework (integrating ETc, Re, Iwr, and NGWC).
  • FAO-recommended Penman–Monteith model for reference crop evapotranspiration (ET0).
  • Fixed coefficient method for effective precipitation (Re).
  • Inverse Distance Weighting (IDW) method for spatial interpolation of meteorological data.
  • Mann–Kendall (M-K) Trend test for detecting monotonic trends.
  • Sen’s slope estimation for quantifying trend magnitudes.
• Data sources:
  • Meteorological data (1961–2020) from 17 stations of the China Meteorological Network (daily temperature, wind speed, sunshine duration, precipitation, and humidity).
  • Crop data (growth-period information and crop coefficients) from the China Meteorological Yearbook and the Food and Agriculture Organization of the United Nations (FAO).
  • County-level sown area data from municipal statistical yearbooks.

Main Results

• Crop Evapotranspiration (ETc): Summer maize ETc showed a consistent downward trend across all growth stages (e.g., mid-growth stage decline of -1.236 mm·year⁻¹). Winter wheat ETc exhibited a distinct increase, particularly during development and mid-growth stages, under climate warming.
• Effective Precipitation (Re): Summer maize Re showed an initial upward trend, followed by a clear downward trend during mid-growth (-1.012 mm·year⁻¹) and maturity stages. Winter wheat Re generally declined across all growth stages, with the most pronounced decrease during maturity (-0.965 mm·year⁻¹).
• Irrigation Water Requirement (Iwr): Summer maize Iwr displayed a persistent downward trend (e.g., mid-growth stage decline of -1.273 mm·year⁻¹). Winter wheat Iwr showed increasing demand during its critical development and mid-growth phases, indicating widening water supply–demand disparities.
• Net Groundwater Consumption (NGWC) and Annual Net Groundwater Consumption (ANGWC):
  • Winter wheat consistently exhibited negative NGWC (net depletion) throughout all growth stages, with intensifying depletion during mid-growth (-1.144 mm·year⁻¹) and maturity (-1.167 mm·year⁻¹).
  • Summer maize NGWC was positive (net recharge) during initial and development stages but turned negative (net depletion) during the mid-growth stage. A significant upward trend in early-growth NGWC indicated a shift from net recharge to net depletion.
  • Winter wheat remained the dominant driver of groundwater depletion, with its ANGWC increasing from -131.25 × 10⁶ m³ (1991–2000) to -162.02 × 10⁶ m³ (2011–2020), consistently three to four times higher than summer maize.
  • Summer maize ANGWC surged sharply by over 130% from around -19.49 × 10⁶ m³ (before 2010) to -45.36 × 10⁶ m³ (2011–2020), indicating a significant increase in groundwater dependence.
• Spatial Hotspots: The central-northern plains of Henan Province were identified as persistent and intensifying groundwater depletion hotspots for both crops.

Contributions

• Systematically elucidated the mechanisms underlying groundwater depletion within Henan Province’s winter wheat–summer maize rotation system over six decades using a unified water balance framework.
• Revealed a dynamic process of groundwater stress transfer and amplification within the rotation system, characterized by opposite temporal trajectories of water use between the two crops.
• Quantified the sharp post-2010 increase in summer maize groundwater depletion, underscoring the need for an integrated analysis combining climatic, agronomic, and policy drivers.
• Provided empirical evidence for the hydrological consequences of winter wheat fallowing and summer maize water conservation within a consistent analytical framework.
• Proposed a regionally differentiated dual strategy, integrating targeted winter wheat fallowing with strict irrigation quotas and water-saving technologies for summer maize, to achieve sustainable groundwater management.

Funding

• Key Scientific Research Project of Henan Higher Education Institutions, grant number 23A210021.

Citation

@article{Zhang2025Spatiotemporal,
  author = {Zhang, Zhao and Wang, Jing and Ning, Jing and Ti, Jinsong},
  title = {Spatiotemporal dynamics of crop water use and groundwater depletion under the winter wheat–summer maize rotation system in Henan Province, China},
  journal = {Frontiers in Plant Science},
  year = {2025},
  doi = {10.3389/fpls.2025.1728535},
  url = {https://doi.org/10.3389/fpls.2025.1728535}
}