Liu et al. (2026) Global quantification of the bidirectional dependence between vegetation productivity and multi-layer soil moisture

Identification

• Journal: Journal of Hydrology
• Year: 2026
• Date: 2026-01-30
• Authors: Ying Liu, Jiumeilin Shi, Hui Yue, Xu Wang
• DOI: 10.1016/j.jhydrol.2026.135065

Research Groups

College of Geomatics, Xi’an University of Science and Technology, Xi’an 710054, China

Short Summary

This study globally quantified the bidirectional dependence between vegetation productivity and multi-layer soil moisture using Granger causality, revealing that interaction strength varies significantly with soil depth, climate zone, and vegetation type.

Objective

• To explore and quantify the bidirectional Granger causality between vegetation productivity and multi-layer soil moisture across different climate zones, vegetation types, and soil depths globally.

Study Configuration

• Spatial Scale: Global
• Temporal Scale: Not explicitly defined in the provided text, but implied to be multi-year for trend analysis.

Methodology and Data

• Models used: Granger causality model, trend analysis, causal inference, multiple linear regression.
• Data sources: Global Solar Induced Chlorophyll Fluorescence (SIF), multi-layer soil moisture datasets, average air temperature at 2 m datasets, solar radiation datasets.

Main Results

• Widespread bidirectional dependence was found between vegetation productivity and soil moisture across all soil layers.
• Interaction strength declined with soil depth, from 79.84% in the surface layer (0–0.1 m) to 72.04% in the deep layer (1.0–2.0 m).
• Bidirectional coupling magnitude varied significantly by climate zone:
  • Temperate regions showed peak dependence in surface soils (82.52%).
  • Tropical zones exhibited maxima in shallow (82.99%) and deep (78.05%) layers.
  • Boreal zones showed the strongest dependence in the middle soil layer (76.25%).
• Woody plants demonstrated higher average bidirectional dependence (79.4%) than herbaceous plants (75.75%), while shrubland vegetation showed relatively lower dependence (74%).
• Tropical zones (dominated by evergreen broadleaf forests) and boreal zones (dominated by shrublands) both showed peak bidirectional dependence in the shallow soil layer. Other climate zones, primarily influenced by grassland vegetation, exhibited peak dependence within the surface soil layer.

Contributions

This study provides a global, quantitative characterization of the bidirectional dependence between vegetation productivity and multi-layer soil moisture, highlighting its variability across climate zones, vegetation types, and soil depths, thereby offering a robust theoretical foundation for improved regional soil moisture regulation and ecosystem restoration.

Funding

Not explicitly mentioned in the provided text.

Citation

@article{Liu2026Global,
  author = {Liu, Ying and Shi, Jiumeilin and Yue, Hui and Wang, Xu},
  title = {Global quantification of the bidirectional dependence between vegetation productivity and multi-layer soil moisture},
  journal = {Journal of Hydrology},
  year = {2026},
  doi = {10.1016/j.jhydrol.2026.135065},
  url = {https://doi.org/10.1016/j.jhydrol.2026.135065}
}