FprEN 18318
(Main)Organo-mineral fertilizers - Determination of specific inhibiting compounds
- Abstract
This document specifies references to methods for determining the content 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 plant biostimulants.
- Status
- Not Published
- Publication Date
- 03-Feb-2027
- Technical Committee
- CEN/TC 260 - Fertilizers and liming materials
- Drafting Committee
- CEN/TC 260/WG 7 - Chemical analysis
- Current Stage
- 5020 - Submission to Vote - Formal Approval
- Start Date
- 15-Oct-2026
- Due Date
- 20-Sep-2027
- Completion Date
- 15-Oct-2026
FprEN 18318 is a draft European Standard from CEN for organo-mineral fertilizers. It specifies which methods to use to determine the content of specific urease inhibiting compounds, especially N-(n-butyl)thiophosphoric triamide (NBPT) and N-(2-nitrophenyl)phosphoric triamide (2-NPT), in the fertilizing product blends covered by its scope.
What does FprEN 18318 specify?
FprEN 18318 applies to fertilizing product blends made from at least two components, where the blend includes organic fertilizers and inorganic fertilizers to which urease inhibitors have been added. It is aimed at determining the content of urease inhibiting compounds in those organo-mineral fertilizers.
| Part of the document | What it covers |
|---|---|
| Clause 1 | Scope and applicability |
| Clause 2 | Normative references |
| Clause 3 | Terms and definitions |
| Clause 4 | Sampling and sample preparation |
| Clause 5 | Determination of urease inhibiting compound content |
| Annex ZA | Relationship to Regulation (EU) 2019/1009 |
The scope excludes fertilizing product blends containing liming materials, soil conditioners, growing media or plant biostimulants. In practice, that matters because the standard is intended for a specific product type and a specific analytical question, so users need to check product composition before choosing it.
What are the key requirements of FprEN 18318?
FprEN 18318 is mainly a reference document: it tells users which established methods to apply, rather than setting out a full analytical procedure in one place. The practical value is that laboratories, manufacturers and conformity assessment bodies can follow a common route when checking NBPT and 2-NPT in scope.
Clause 4.1 - Sampling is outside the method, and the document points users to a recommended sampling method in EN 1482-1. The sample should represent the product as placed on the market and should not be altered during transport or storage. This matters because a poor sample can give a misleading result even if the analysis is performed correctly.
Clause 4.2 - Sample preparation follows EN 1482-2:2024. Users prepare the laboratory sample according to that standard before any measurement step. In practice, this keeps the test material consistent and reduces variation between laboratories.
Clause 5.1 - NBPT is determined according to prEN 18317:2026. FprEN 18318 directs users to the dedicated NBPT method instead of describing a separate test here. That means anyone checking NBPT needs to use the referenced method and report results from that procedure.
Clause 5.2 - 2-NPT is determined according to EN 16075:2011. The referenced method uses high-performance liquid chromatography (HPLC). In practice, this gives laboratories a defined route for measuring 2-NPT in urea-containing fertilizers.
Clause 3 - Terms and definitions come from prEN 12944-1:2026 and prEN 12944-2:2026. This keeps the vocabulary aligned with the wider fertilizers and liming materials series, which helps avoid ambiguity in specifications, reports and contracts.
Introduction and Annex ZA link the technical work to EU fertilising product requirements. The introduction says organo-mineral fertilizers are classified as PFC 1(B), and Annex ZA maps the standard to Regulation (EU) 2019/1009. For users, that is the bridge between laboratory data and market access documentation.
What terms does FprEN 18318 define?
- Organo-mineral fertilizers - Fertilizers that combine organic and inorganic components, and are the product type covered by this standard.
- Fertilizing product blends - Blends made from at least two components in the scope description, used here for mixtures of organic fertilizers and inorganic fertilizers with added urease inhibitors.
- Urease inhibiting compounds - The compounds whose content is measured by the standard, because they affect how the fertilizer performs.
- NBPT - N-(n-butyl)thiophosphoric triamide, one of the specific urease inhibiting compounds covered by Clause 5.
- 2-NPT - N-(2-nitrophenyl)phosphoric triamide, the other specific compound covered by Clause 5.
- PFC 1(B) - The product function category named in the introduction for organo-mineral fertilizers in EU fertilizing products.
Who uses FprEN 18318?
FprEN 18318 is used by fertilizer manufacturers, contract laboratories, quality managers and conformity assessment bodies that need to verify inhibitor content in organo-mineral fertilizer blends. It also matters to buyers and regulators who need a common technical basis for product specifications, test reports and EU compliance checks.
In practice, users apply it when they need to sample a batch, prepare the sample correctly, choose the right analytical method for NBPT or 2-NPT, and document results in a way that can support product release or conformity work.
Which standards are used with FprEN 18318?
- EN 1482-2:2024 - Gives the sample preparation provisions used in Clause 4.2.
- EN 1482-1 - Provides the recommended sampling method mentioned in Clause 4.1.
- prEN 12944-1:2026 - Supplies general terms used for interpretation of the document.
- prEN 12944-2:2026 - Supplies fertilizer-specific terms used for interpretation of the document.
- prEN 18317:2026 - Gives the method for determining NBPT content.
- EN 16075:2011 - Gives the HPLC method for determining 2-NPT content.
What does the FprEN 18318 document contain?
The document contains a short, method-linked structure: scope, normative references, terms and definitions, sampling and sample preparation, and two substance-specific determination clauses. Its technical core is the referral to EN 1482-2, prEN 18317 and EN 16075, so the user knows which procedure to use for each compound.
Annex ZA provides the correspondence with Regulation (EU) 2019/1009 and includes a table linking the standard to the relevant essential safety requirements. The bibliography then points to the regulation itself and EN 1482-1 for sampling guidance.
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Frequently Asked Questions
FprEN 18318 is a draft published by the European Committee for Standardization (CEN). Its full title is "Organo-mineral fertilizers - Determination of specific inhibiting compounds". This standard covers: This document specifies references to methods for determining the content 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 plant biostimulants.
This document specifies references to methods for determining the content 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 plant biostimulants.
FprEN 18318 is classified under the following ICS (International Classification for Standards) categories: 65.080 - Fertilizers. The ICS classification helps identify the subject area and facilitates finding related standards.
FprEN 18318 is associated with the following European legislation: EU Directives/Regulations: 2019/1009; Standardization Mandates: M/564, M/564 Amd 1, M/564 Amd 2. When a standard is cited in the Official Journal of the European Union, products manufactured in conformity with it benefit from a presumption of conformity with the essential requirements of the corresponding EU directive or regulation.
FprEN 18318 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
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
prEN 18318
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.
prEN 18318:2026 (E)
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
prEN 18318:2026 (E)
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.
prEN 18318:2026 (E)
Introduction
Different product functions warrant different product safety and quality requirements adapted to their
...