Global Soil Hydraulic Properties dataset based on legacy site observations and robust parameterization

Area of Science:

• Hydrology
• Soil Science
• Climate Science

Background:

• Soil water characteristics curves (SWCCs) are crucial for modeling land surface processes, plant water availability, and vadose zone water storage.
• Existing SWCC data require harmonization for effective use in hydrological and climatic models.
• Accurate SWCC parameters are essential for reliable simulations of water movement and storage in soils.

Purpose of the Study:

• To assemble, harmonize, and quality-check a comprehensive global dataset of SWCCs.
• To create a Global Soil Hydraulic Properties (GSHP) database for modeling applications.
• To estimate SWCC parameters using the van Genuchten (vG) model and pedotransfer functions (PTFs).

Main Methods:

• Compiled 15,259 SWCCs from 2,702 sites across published literature.
• Harmonized and quality-checked the assembled SWCC data.
• Estimated van Genuchten (vG) model parameters using the 'soilhypfit' R package and utilized PTFs for missing wet/dry-end data.

Main Results:

• Established the Global Soil Hydraulic Properties (GSHP) database, a valuable resource for researchers.
• Quantified variations in SWCCs across different climatic regions.
• Provided a foundation for generating global maps of soil hydraulic properties.

Conclusions:

• The GSHP database significantly advances the representation of soil water dynamics in Earth system models.
• The harmonized SWCC data enable more accurate estimations of soil water storage and plant water availability.
• This work facilitates improved global-scale hydrological and climatic simulations.