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FAO Soils - LinkML Schemas

Standardized, machine-readable schemas for FAO soil databases

This documentation site provides comprehensive information about LinkML schemas for FAO (Food and Agriculture Organization) soil databases.

Schemas

HWSD2 - Harmonized World Soil Database v2.0

The HWSD v2.0 is a comprehensive global soil dataset with 30 arc-second resolution (~1 km) covering physical, chemical, and hydrological soil properties at 7 depth layers (0-200 cm).

Key features: - 58,405 soil mapping units globally - 408,835 layer records (7 layers × 58,405 sequences) - Physical properties: texture, bulk density, coarse fragments - Chemical properties: organic carbon, pH, nitrogen, CEC - Multiple classification systems: WRB, FAO-90, USDA

Using the Schemas

Installation

pip install linkml linkml-runtime

Generate Python Dataclasses

gen-python src/fao_soils/schema/hwsd2.yaml > hwsd2_model.py

Generate Other Formats

# JSON Schema
gen-json-schema src/fao_soils/schema/hwsd2.yaml > hwsd2.schema.json

# SQL DDL
gen-sqlddl src/fao_soils/schema/hwsd2.yaml > hwsd2.sql

# Markdown documentation
gen-markdown src/fao_soils/schema/hwsd2.yaml > hwsd2_docs.md

# OWL ontology
gen-owl src/fao_soils/schema/hwsd2.yaml > hwsd2.owl

Applications

Ecosystem Modeling

  • Extract soil profiles by geographic coordinates
  • Parameterize biogeochemical models (EcoSIM, CENTURY, DayCENT)
  • Multi-site comparative studies
  • Climate change impact assessments

Data Integration

  • Standardized vocabulary for soil properties
  • Validation of soil data quality
  • Interoperability with environmental databases
  • Reproducible research workflows

Resources

Contributing

Contributions are welcome! See our GitHub repository for contribution guidelines.

License

  • Schema files: BSD-3-Clause
  • HWSD v2.0 data: CC-BY-4.0 (provided by FAO)