Overview
ISO 10930:2012 - "Soil quality - Measurement of the stability of soil aggregates subjected to the action of water" defines a standardized laboratory method to assess the structural stability of soil aggregates (3–5 mm fraction) when exposed to water. The standard prescribes sample collection, preparation, three wetting/disaggregation treatments (fast wetting, slow capillary wetting, and mechanical disaggregation after ethanol immersion), sieving and mass determination, and calculation of the mean weighted diameter (MWD) to quantify aggregate stability. It is intended for tilled horizons and other soil profile horizons but does not apply to unstructured materials.
Key topics and technical requirements
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Sample scope and preparation
- Test aggregates in the 3 mm–5 mm size range; record and account for gravel content.
- Air-dry samples promptly, pass through 5 mm then 3 mm sieves, oven-dry at 40 °C for 24 h before testing.
- Field sampling guidance: ~1 kg sample, transport to avoid aggregate breakage; sampling time consistency recommended.
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Three prescribed treatments
- Treatment 1 - Fast wetting by immersion: simulates sudden wetting (heavy rain/irrigation); observe slaking, then transfer to 0.05 mm sieve in ethanol.
- Treatment 2 - Slow wetting by capillarity: simulates moderate rain; rewet on humid filter paper above a permeable block, then transfer to ethanol-immersed sieve.
- Treatment 3 - Mechanical disaggregation after ethanol immersion: simulates wet mechanical stresses; aggregates immersed in ethanol then shaken in water.
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Equipment and reagents
- 95% ethanol, sieving device producing helical movement (Hénin-Féodoroff recommended), set of stainless steel sieves (5.0 to 0.05 mm per ISO 3310‑1), balance (±1 mg), ovens, wash bottles, filter papers.
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Measurement and calculation
- Sieving in ethanol, dry and re-sieve to obtain size distribution; calculate MWD from the percentage mass in size classes (correct for gravel if 10–40% present; tests not significant if gravel >40%).
Applications
- Predicting soil behavior under rainfall or irrigation events
- Comparing structural stability of cultivated soils and different management practices
- Soil erosion risk assessment, land management, conservation planning
- Research on soil aggregation, tillage impacts, amendment effects (e.g., organic matter)
- Soil scientists and agronomists
- Environmental and geotechnical laboratories
- Agricultural extension services and land managers
- Researchers studying soil structure, erosion, and soil quality indicators
Related standards
- ISO 3310-1:2000 - Test sieves (referenced for sieve specifications)
- Prepared under ISO/TC 190 (Soil quality); Annexes in ISO 10930 provide flow diagrams, result presentation examples, and method repeatability data.
Keywords: ISO 10930, soil aggregate stability, soil quality, mean weighted diameter, aggregate stability test, soil sampling, soil structure, erosion risk.