Yan et al. (2025) Southward shift of winter wheat area intensifies regional water scarcity in the Beijing-Tianjin-Hebei region

Identification

• Journal: Frontiers in Sustainable Food Systems
• Year: 2025
• Date: 2025-11-24
• Authors: Qi Yan, Lang Xia, Fen Zhao, Yan Zha, Lingling Fan, Peng Yang
• DOI: 10.3389/fsufs.2025.1674652

Research Groups

• 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, China
• Key Laboratory of Agricultural Remote Sensing (AGRIRS), Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
• Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
• Agricultural Information Institute, Chinese Academy of Agricultural Sciences, Beijing, China

Short Summary

This study analyzed winter wheat planting dynamics and water resource implications in the Beijing-Tianjin-Hebei (BTH) region from 1990-2019, revealing a 58 km southward shift of cultivation that intensified regional water scarcity, with a 2.6-fold higher unit-area water footprint increase in southern areas and a 68.7% surge in blue water requirement.

Objective

• To analyze the spatial–temporal impact of the spatial distribution evolution of winter wheat in the North China Plain from 1990 to 2019 on water resource utilization based on high-resolution remote sensing data.

Study Configuration

• Spatial Scale: Beijing-Tianjin-Hebei (BTH) region, North China Plain, China (113°27′E to 119°50′E and 36°05′N to 42°40′N).
• Temporal Scale: 1990 to 2019 (analyzed at 1990, 2000, 2010, and 2019 time points).

Methodology and Data

• Models used:
  • Phenology-based crop mapping algorithm (PBA) for winter wheat extraction.
  • Vector dot product for similarity measurement of NDVI time series.
  • Maximum interclass variance (Otsu) for threshold determination.
  • Crop coefficient method (FAO-56) for crop water requirement (ETc) calculation.
  • Penman-Monteith method (FAO-56) for reference evapotranspiration (ET0) calculation.
  • Simplified method for effective rainfall calculation.
• Data sources:
  • Multi-source remote sensing data: Landsat 5 (TM) and Landsat 8 (OLI) Surface Reflectance images (Level 1 Terrain-corrected, L1T) from the Google Earth Engine (GEE) platform.
  • Meteorological data: Daily average, maximum, minimum temperature, precipitation, wind speed, sunshine duration, and relative humidity from 145 meteorological stations in BTH (1989-2019).
  • Field survey data: 872 ground truth sites (592 winter wheat, 280 non-wheat) collected in April 2019 using GPS receivers.
  • Validation data: Google Earth very high-resolution (VHR) images.
  • Auxiliary data: Agricultural statistical data (county/municipal level) for winter wheat irrigation area and farmland irrigation water consumption (1990-2013), 90 m resolution Digital Elevation Model (DEM) from GEE.

Main Results

• The developed phenology-based algorithm achieved high accuracy for winter wheat mapping, with an overall accuracy of 93% and a Kappa coefficient of 0.89.
• Winter wheat planting area in the BTH region exhibited three distinct phases from 1990 to 2019: initial increase, subsequent decrease, and eventual stabilization.
• A significant southward shift in winter wheat spatial distribution was observed, with the planting centroids migrating 58 km over 30 years.
• This southward shift led to substantial water resource disparities: the unit-area water footprint in southern regions increased 2.6 times more than in northern areas (p < 0.01).
• The blue water requirement for winter wheat surged by 68.7%, reaching 11.3 billion cubic meters, while available green water declined by 72.0%.
• The study identified a "triple decoupling" phenomenon, reflecting a spatial imbalance in the "nature—production—engineering" elements of the regional agricultural water resources system, with a 44 km mismatch between the irrigation system and planting layout migration.

Contributions

• Developed and validated a high-precision, adaptive threshold-based algorithm for long-term (1990-2019), high-resolution (Landsat-derived) winter wheat spatial distribution mapping in the BTH region.
• Provided a comprehensive spatiotemporal assessment of winter wheat planting dynamics and its hydrological impacts, quantifying changes in total, blue, and green water requirements and footprints.
• Revealed a critical southward migration of winter wheat cultivation and its direct link to intensified regional water scarcity, particularly highlighting the increasing reliance on blue water (irrigation) and declining green water (rainfall) utilization.
• Identified the spatial heterogeneity of water resource sensitivity to cropland changes, emphasizing the need for region-specific water management strategies.
• Established a critical baseline for evaluating the effectiveness of stringent groundwater governance policies implemented after 2019 in the North China Plain.

Funding

• National Natural Science Foundation of China (Award Nos. 42201112 and 32471999)
• Youth Innovation Program of the Chinese Academy of Agricultural Sciences (Y2025QC11)
• National Key Research and Development Program of China (Award No. 2022YFD2001105)
• Central Public-interest Scientific Institution Basal Research Fund (Award No. JBYW-AII-2025-40)

Citation

@article{Yan2025Southward,
  author = {Yan, Qi and Xia, Lang and Zhao, Fen and Zha, Yan and Fan, Lingling and Yang, Peng},
  title = {Southward shift of winter wheat area intensifies regional water scarcity in the Beijing-Tianjin-Hebei region},
  journal = {Frontiers in Sustainable Food Systems},
  year = {2025},
  doi = {10.3389/fsufs.2025.1674652},
  url = {https://doi.org/10.3389/fsufs.2025.1674652}
}