prEN 15957

Overview

prEN 15957: Inorganic fertilizers - Extraction of phosphorus which is soluble in neutral ammonium citrate is a draft European Standard developed by CEN/TC 260, focusing on fertilizers and liming materials. This document specifies a standardized method for extracting phosphorus that is soluble in neutral ammonium citrate from inorganic fertilizers. The procedure supports accurate analysis and classification of fertilizer products by defining a clear protocol for sample preparation, reagent use, and extraction conditions.

Phosphorus availability is a critical quality parameter for inorganic fertilizers, directly influencing their effectiveness in agricultural applications. This standard ensures consistency, repeatability, and comparability of test results across laboratories and jurisdictions within Europe.

Key Topics

• Extraction Methodology
  The standard details the procedure for the extraction of phosphorus using a neutral ammonium citrate solution at pH 7, under controlled conditions at 65°C for one hour.
• Sample Preparation
  Emphasizes representative sampling and proper preparation to ensure homogeneity and reliability of analytical results.
• Reagent Specifications
  Only high-quality, analytically recognized-grade reagents are permitted, with special requirements for the water and the ammonium citrate solution.
• Apparatus Requirements
  Lists specific laboratory equipment, such as pH-meters, Erlenmeyer flasks, thermostatic water baths, and phosphate-free filters, necessary for the test.
• Reporting Standards
  Test reports must provide full traceability and detail, including identification, test method, procedures, date of extraction, and any deviations.

Applications

The standardized extraction of citrate-soluble phosphorus plays a vital role in multiple areas:

• Fertilizer Quality Assessment
  Enables manufacturers and regulatory bodies to determine the plant-available phosphorus content, ensuring fertilizers meet legal and agronomic requirements.
• Regulatory Compliance
  Supports traceability, documentation, and compliance with European Union regulations for inorganic fertilizer products.
• Product Development and R&D
  Assists manufacturers in developing formulations with optimal nutrient release profiles by providing reliable analytical data.
• Trade and Market Transparency
  Harmonizes testing procedures across member states, helping ensure fair trade and mutual recognition of analytical results in the fertilizer sector.
• Environmental Monitoring
  Assists in monitoring phosphorus leachability and environmental impact from fertilizer application.

Related Standards

For effective implementation and integration, prEN 15957 references and complements several other standards:

• EN 1482-2
  Fertilizers, liming materials and inhibitors - Sampling and sample preparation - Part 2: General sample preparation provisions
  Essential guidance for sampling and preparation, crucial for ensuring analytical validity.

• EN 12944-1 & EN 12944-2
  Fertilizers and liming materials - Vocabulary - Part 1: General terms
  Fertilizers and liming materials - Vocabulary - Part 2: Terms relating to fertilizers
  Define terminology, promoting consistency in interpretation and compliance.

• EN 1482-1 (Bibliography)
  Fertilizers, liming materials and inhibitors - Sampling and sample preparation - Part 1: General sampling provisions

Practical Value

By providing a unified method for extracting phosphorus soluble in neutral ammonium citrate, prEN 15957 enhances the accuracy and credibility of fertilizer analysis. Adoption of this standard fosters industry best practices, supports regulatory enforcement, and underpins sustainable agriculture by ensuring that the declared phosphorus content aligns with actual plant-available nutrients in the field. This contributes to efficient fertilizer use, environmental protection, and robust market confidence in product labelling and performance.