Overview
ISO 17323:2015 is an international standard that defines the general requirements for Sulfur Coated Urea (SCU), a slow-release fertilizer widely used in agriculture. Developed by the International Organization for Standardization (ISO), this standard addresses essential aspects such as product quality, sampling, testing procedures, marking and labeling, as well as packaging, transportation, and storage of SCU products. The sulfur coating acts as an impermeable barrier, controlling the release of nitrogen to the soil, thereby enhancing fertilizer efficiency while minimizing environmental impact.
Key Topics
SCU Product Requirements
- Nutrient content: Total nitrogen content ranges between 31% and 42%, and sulfur content must be at least 8%.
- Dissolution rates: One Day Dissolution Rate (1DDR) should be ≤40%, and Seven Day Dissolution Rate (7DDR) ≤60%, indicating effective controlled-release behavior.
- Purity indicators: Biuret content is limited to ≤1.2%, and water content must not exceed 1%.
- Granule size: Particle diameters should be within 1.00 mm to 4.75 mm for at least 90% of the batch.
- Appearance: Product must be in granule form with uniform sulfur coating.
Sampling and Test Sample Preparation
- Sampling methods: Differentiated for products in bags and bulk, following ISO 8633 guidelines to avoid damage to the sulfur coating.
- Sample reduction: Uniform mixing with riffle sample divider or quartering method (per ISO 7742) to prepare a representative sample.
- Test sample preparation: Grinding samples to specified particle size while maintaining original characteristics to ensure accurate testing for nitrogen, sulfur, biuret, moisture content, and dissolution rates.
Marking and Labelling
- Essential information includes:
- Total nitrogen and sulfur content
- Date of production
- Net mass and batch identification
- Manufacturer’s name and address
- Labels should comply with applicable national regulations and the Globally Harmonized System (GHS) for chemical classification and labeling.
Packaging, Transport, and Storage
- Packaging must protect against moisture, sunlight, and mechanical damage.
- Storage recommendations specify cool, dry conditions shielded from direct sunlight to maintain product integrity during handling and distribution.
- Compliance with regional safety standards and guidelines is required for all stages of handling.
Applications
ISO 17323:2015 applies primarily to the agricultural sector where SCU is used as a controlled-release fertilizer to improve nutrient management and crop yields. Its application includes:
- Enhancing nitrogen use efficiency by reducing nutrient losses from volatilization, leaching, and runoff.
- Providing a secondary nutrient source through sulfur, essential for plant growth and soil health.
- Supporting sustainable farming practices by minimizing environmental pollution.
- Suitable for a wide variety of crops where precise nutrient delivery over time is critical.
Fertilizer manufacturers and distributors rely on this standard to ensure product consistency, safety, and performance, facilitating international trade and regulatory compliance.
Related Standards
- ISO 7409: Fertilizers - Marking - Presentation and declarations
- ISO 7410: Fertilizers and soil conditioners - Final samples - Practical arrangements
- ISO 7742: Solid fertilizers - Reduction of samples
- ISO 8157: Fertilizers and soil conditioners - Vocabulary
- ISO 8633: Solid fertilizers - Simple sampling method for small lots
- ISO 17322: Fertilizers and soil conditioners - Analytical methods for SCU
These complementary ISO standards cover detailed aspects of fertilizer testing, definitions, sampling, and marking, providing a comprehensive framework for quality assurance and regulatory adherence in the fertilizer industry.
Keywords: ISO 17323, Sulfur Coated Urea, SCU, slow-release fertilizer, fertilizer standards, sulfur coating, nitrogen fertilizer, fertilizer sampling, fertilizer labeling, fertilizer packaging, agricultural fertilizers, controlled-release fertilizer, fertilizer transport and storage.