prEN 18318

Organo-mineral fertilizers - Determination of specific inhibiting compounds

This document specifies references to the methods for the determination of urease inhibiting compounds in organo-mineral fertilizers.
This document is applicable to fertilizing product blends where the blend is a mix of at least two of the following components: organic fertilizers and inorganic fertilizers to which urease inhibitors have been added.
This document is not applicable to fertilizing product blends containing liming materials, soil conditioners, growing media or biostimulants.

Organisch-mineralische Düngemittel - Bestimmung spezifischer Hemmstoffe

In diesem Dokument sind Verweisungen auf Verfahren zur Bestimmung von ureasehemmenden Verbindungen in organisch-mineralischen Düngemitteln aufgeführt.
Dieses Dokument ist für Düngeproduktmischungen anwendbar, wenn die Mischung aus mindestens zwei der folgenden Komponenten besteht: organische Düngemittel und anorganische Düngemittel, denen Ureasehemmstoffe zugegeben wurden.
Dieses Dokument ist nicht auf Düngeproduktmischungen anwendbar, die Kalkdünger, Bodenverbesserungsmittel, Kultursubstrate oder Biostimulanzien enthalten.

Engrais organo-minéraux - Détermination des composés inhibiteurs spécifiques

Le présent document spécifie les références aux méthodes de dosage des composés inhibiteurs d’uréase dans les engrais organo-minéraux.
Le présent document est applicable aux mélanges de fertilisants constitués d’au moins deux des composants suivants: engrais organiques et engrais inorganiques auxquels des inhibiteurs d’uréase ont été ajoutés.
Le présent document n’est pas applicable aux mélanges de fertilisants contenant des amendements minéraux basiques, des amendements, des supports de culture ou des biostimulants.

Organsko-mineralna gnojila - Določanje specifičnih inhibitorjev

General Information

• Status: Not Published
• Publication Date: 09-Jan-2028
• ICS: 65.080 - Fertilizers
• Technical Committee: CEN/TC 260 - Fertilizers and liming materials
• Drafting Committee: CEN/TC 260/WG 7 - Chemical analysis
• Current Stage: 4020 - Submission to enquiry - Enquiry
• Start Date: 26-Feb-2026
• Due Date: 24-Aug-2026
• Completion Date: 26-Feb-2026
• Directive: Not Harmonized2019/1009 - Regulation (EU) 2019/1009 of the European Parliament and of the Council of 5 June 2019 laying down rules on the making available on the market of EU fertilising products and amending Regulations (EC) No 1069/2009 and (EC) No 1107/2009 and repealing Regulation (EC) No 2003/2003 (Text with EEA relevance)
• Mandate: M/564 - Fertilising products in support of Regulation (EU) 2019/1009
• Mandate: M/564 AMD 1 - amending Implementing Decision C(2020) 612 as regards certain harmonised standards and standardisation deliverables, deadlines for their adoption and the duration of the validity of the standardisation request
• Mandate: M/564 AMD 2 - Commission Implementing decision amending Implementing Decision C(2020)612 as regards harmonised standards, the deadlines for the adoption of those standards and the duration of the validity of the standardisation request to the European Committee for Standardisation as regards the EU fertilising products in support of Regulation (EU) 2019/1009 of the European Parliament and of the Council
• Ref Project: oSIST prEN 18318:2026 - Organo-mineral fertilizers - Determination of specific inhibiting compounds

Overview

prEN 18318 is a draft European Standard developed by the CEN/TC 260 technical committee. This standard outlines reference methods for the determination of urease inhibiting compounds in organo-mineral fertilizers. Its primary goal is to ensure accurate identification and measurement of specific inhibiting substances, supporting regulatory compliance and promoting responsible fertilizer use within the EU. The scope specifically covers blended fertilizing products composed of at least two of the following: organic fertilizers and inorganic fertilizers containing urease inhibitors.

The standard does not apply to blends containing liming materials, soil conditioners, growing media, or biostimulants. By referencing prEN 18318, manufacturers and laboratories can ensure consistency in quality control and meet the regulatory requirements set out in Regulation (EU) 2019/1009 for organo-mineral fertilizers.

Key Topics

• Determination Methods: The standard references analytical procedures for detecting and quantifying urease inhibiting compounds commonly found in enhanced efficiency fertilizers.
  • N-(n-butyl)thiophosphoric triamide (NBPT): Method specified in prEN 18317.
  • N-(2-nitrophenyl)phosphoric triamide (2-NPT): Method based on EN 16075:2011 using high-performance liquid chromatography (HPLC).
• Sampling and Sample Preparation: While sampling methods are not directly covered, prEN 18318 points to established standards (EN 1482-1 and EN 1482-2) to ensure representative and uncontaminated samples for analysis.
• Terminology: The standard aligns with prEN 12944-1 and prEN 12944-2 for consistent vocabulary regarding fertilizers and related materials.
• Regulatory Alignment: Provides a pathway for demonstrating conformity with the EU Fertilising Products Regulation (2019/1009), specifically for organo-mineral products in Product Function Category (PFC) 1(B).

Applications

prEN 18318 delivers practical benefits throughout the organo-mineral fertilizer supply chain, including:

• Manufacturers: Enables producers to verify the presence and concentration of urease inhibitors in product blends, helping to ensure product quality and regulatory conformity.
• Testing Laboratories: Provides standardized reference methods for analyzing fertilizers, supporting reliable and comparable results across EU member states.
• Regulators: Facilitates market surveillance and enforcement by offering harmonized techniques to check compliance with EU requirements for organo-mineral fertilizers.
• Importers and Distributors: Ensures products coming into the EU market meet the essential safety and quality criteria related to inhibiting compounds.

Proper implementation of prEN 18318 supports the development of organo-mineral fertilizers with enhanced nitrogen use efficiency, helping to reduce ammonia volatilization and improve environmental sustainability in agriculture.

Related Standards

For a comprehensive approach to organo-mineral fertilizer analysis, prEN 18318 references and complements several other key standards:

• EN 1482-1: Fertilizers, liming materials, and inhibitors - Sampling and sample preparation - Part 1: General sampling provisions
• EN 1482-2: Fertilizers, liming materials, and inhibitors - Sampling and sample preparation - Part 2: General sample preparation provisions
• prEN 12944-1: Fertilizers, liming materials, and inhibitors - Vocabulary - Part 1: General terms
• prEN 12944-2: Fertilizers, liming materials, and inhibitors - Vocabulary - Part 2: Terms relating to fertilizers
• prEN 18317: Organo-mineral fertilizers - Determination of the NBPT urease inhibitor content
• EN 16075:2011: Fertilizers – Determination of 2-NPT in urea and fertilizers containing urea by HPLC

These related standards ensure rigorous and harmonized approaches to sampling, terminology, and analytical methods, supporting the quality and trustworthiness of fertilizer products across the European market.

Standards Content (Sample)

SLOVENSKI STANDARD
01-april-2026
Organsko-mineralna gnojila - Določanje specifičnih inhibitorjev
Organo-mineral fertilizers - Determination of specific inhibiting compounds
Organisch-mineralische Düngemittel - Bestimmung spezifischer Hemmstoffe
Engrais organo-minéraux - Détermination des composés inhibiteurs spécifiques
Ta slovenski standard je istoveten z: prEN 18318
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2026
ICS 65.080
English Version
Organo-mineral fertilizers - Determination of specific
inhibiting compounds
Engrais organo-minéraux - Détermination des Organisch-mineralische Düngemittel - Bestimmung
composés inhibiteurs spécifiques spezifischer Hemmstoffe
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 260.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 18318:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Sampling and sample preparation . 5
4.1 Sampling . 5
4.2 Sample preparation . 5
5 Determination of the urease inhibiting compound content . 6
5.1 Determination of N-(n-butyl)thiophosphoric triamide (NBPT). 6
5.2 Determination of N-(2-nitrophenyl)phosphoric triamide (2-NPT) . 6
Annex ZA (informative) Relationship of this European Standard and the essential requirements
of Regulation (EU) 2019/1009 making available on the market of EU fertilising products
aimed to be covered . 7
Bibliography . 8

European foreword
This document (prEN 18318:2026) has been prepared by Technical Committee CEN/TC 260 “Fertilizers
and liming materials”, the secretariat of which is held by DIN.
This document is currently submitted to CEN Enquiry.
This document has been prepared under a standardization request addressed to CEN by the European
Commission. The Standing Committee of the EFTA States subsequently approves these requests for its
Member States.
For the relationship with EU Legislation, see informative Annex ZA, which is an integral part of this
document.
Introduction
Different product functions warrant different product safety and quality requirements adapted to their
...