Guo et al. (2025) The inclusion of time-lag response reveals contrasting effects of meteorological and agricultural drought on agroecosystem water use efficiency in Africa

Identification

• Journal: Journal of Hydrology
• Year: 2025
• Date: 2025-10-04
• Authors: Xinya Guo, Zhenke Zhang, Xingqi Zhang, Shouming Feng
• DOI: 10.1016/j.jhydrol.2025.134346

Research Groups

• School of Geography and Ocean Sciences, Nanjing University, Nanjing 210023, China
• Institute of Geographical Science, Taiyuan Normal University, Jinzhong 030619, China
• Institute of African Studies, Nanjing University, Nanjing 210023, China
• Collaborative Innovation Center of South China Sea Studies, Nanjing University, Nanjing 210093, China

Short Summary

This study disentangles the contrasting time-lag effects of meteorological and agricultural droughts on agroecosystem water use efficiency (WUE) in Africa, revealing agricultural drought as the predominant contributor with a longer time-lag and distinct thresholds for abrupt shifts in WUE.

Objective

• To investigate how time-lag effects vary between meteorological and agricultural droughts and how these distinct droughts affect agroecosystem water use efficiency (WUE) in Africa, focusing on their contributions and thresholds for abrupt shifts in WUE.

Study Configuration

• Spatial Scale: Africa
• Temporal Scale: Growing season; time-lag responses of 2-3 months (meteorological drought) and 3-6 months (agricultural drought).

Methodology and Data

• Models used: Partial correlation and time-lag analysis; elastic based method (for contribution analysis); R package chngpt (for drought threshold identification).
• Data sources: Implied from drought definitions (precipitation deficit, soil moisture depletion). Specific data sources (e.g., satellite, observation, reanalysis) are not explicitly mentioned in the provided text.

Main Results

• Meteorological and agricultural droughts exhibit contrasting effects on growing-season water use efficiency (WUE).
• Agricultural drought demonstrated a more significant time-lag effect on WUE, with responses lagging 3–6 months.
• WUE responses lagged only 2–3 months behind meteorological drought.
• Agricultural drought was the predominant contributor to nearly 90 % of agroecosystem WUE variation, with deep soil moisture at a depth of 0.4–1.0 meters being particularly influential.
• Drought thresholds, indicating an abrupt shift in WUE's ability to cope with stress, were higher in tropical semi-arid climate zones during agricultural drought.
• The drought threshold for meteorological drought was larger in savannah climate zones.

Contributions

• Reveals the contrasting time-lag effects of meteorological and agricultural droughts on agroecosystem water use efficiency (WUE).
• Quantifies the distinct contributions of different drought types to WUE variation, highlighting the dominant role of agricultural drought.
• Identifies specific drought thresholds for abrupt shifts in WUE, which vary by drought type and climate zone.
• Provides crucial insights for maintaining WUE by pinpointing critical water-limited processes, particularly the importance of deep soil moisture.

Funding

• Not explicitly mentioned in the provided text.

Citation

@article{Guo2025inclusion,
  author = {Guo, Xinya and Zhang, Zhenke and Zhang, Xingqi and Feng, Shouming},
  title = {The inclusion of time-lag response reveals contrasting effects of meteorological and agricultural drought on agroecosystem water use efficiency in Africa},
  journal = {Journal of Hydrology},
  year = {2025},
  doi = {10.1016/j.jhydrol.2025.134346},
  url = {https://doi.org/10.1016/j.jhydrol.2025.134346}
}