Overview
ISO 14820-2:2016, "Fertilizers and liming materials - Sampling and sample preparation - Part 2: Sample preparation", specifies standardized methods for the reduction and preparation of fertilizer and liming-material samples for subsequent chemical and physical testing. The standard covers preparation of test samples and test portions from laboratory samples, requirements for sample preparation reports, and practical apparatus and procedural requirements. It applies to all fertilizers (the term includes liming materials) but does not cover preparation for certain physical tests that require test portions larger than 2 kg.
Key topics and requirements
- Scope and terminology: Defines key terms such as laboratory sample, test sample, reduction, division and test portion.
- General principles: Emphasizes representative reduction/division of laboratory samples to produce test samples and test portions while minimizing moisture loss or gain.
- Apparatus requirements: Specifies suitable equipment including:
- rotary sample divider or riffle divider (per ISO 14820-1),
- sample grinder (preferably enclosed, with screens or mechanisms to avoid over-grinding),
- mortar and pestle,
- test sieves (ISO 3310-1 - nominal apertures 1.0 mm, 0.5 mm and 0.18 mm),
- airtight sample containers (plastic/glass).
- Grinding and temperature control: Grinding must avoid overheating (temperature should not exceed ~45 °C) to prevent loss of volatile components (e.g., ammonium/ammonia). Grinder performance should be checked for fineness, temperature rise and contamination risk.
- Moisture-sensitive handling: Guidance on equipment that can alter moisture content - e.g., single-pass hammer mills are generally acceptable, static “coffee-grinder” types can reduce moisture if used too long, and cyclone mills should not be used for moisture-sensitive samples due to airflow-induced drying.
- Preparation procedures:
- Test samples typically of about 0.5 kg;
- Procedures for preparing test portions for physical testing, moisture analysis, and chemical analysis, including when samples must remain unground (e.g., ammonium nitrate).
- Documentation and labelling: Requirements for sample labelling, storage, and a sample preparation report documenting methods and deviations.
Applications and users
ISO 14820-2 is used by:
- Analytical and agricultural testing laboratories performing fertilizer quality analysis;
- Fertilizer manufacturers and quality control teams for in-plant sampling and sample preparation protocols;
- Regulators and certification bodies that require reproducible, documented sampling and preparation for compliance testing;
- Research institutions and agronomists conducting fertilizer composition or performance studies.
Practical benefits include consistent, reproducible test portions, minimized analytical bias, and documented traceability of sample handling procedures.
Related standards
- ISO 14820-1:2016 - Sampling (companion standard for sampling procedures)
- ISO 3310-1 - Test sieves - technical requirements
- ISO 8157 - referenced for terminology and sample definitions
Keywords: ISO 14820-2, sample preparation, fertilizers and liming materials, test samples, laboratory sample, sample grinder, riffle divider, moisture analysis, chemical analysis, physical testing.