oSIST prEN 17759:2026

• Abstract:

  This document specifies a method for the determination of pH of a solution of ammonium nitrate fertilizer of high nitrogen content.; This document is only applicable to fertilizing product blends with high nitrogen content.; NOTE Variations in analytical methods for fertilizing product blends can lead to differing results as some components or matrix interactions can affect the outcome. Validation procedures have shown that developed standard methods are robust and reliable across diverse product compositions, but possible interferences and unexpected results when analysing fertilizing product blends are possible.

• Status: Not Published
• Public Enquiry End Date: 01-May-2026
• ICS: 65.080 - Fertilizers
• Technical Committee: KAT - Soil quality
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 24-Feb-2026
• Due Date: 14-Jul-2026
• Completion Date: 29-May-2026
• Directive: 2019/1009 - 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: FprEN 17759 - Inorganic fertilizers - Determination of pH of a solution of ammonium nitrate fertilizers of high nitrogen content

• Revises: SIST-TS CEN/TS 17759:2023 - Inorganic fertilizers - Determination of pH of a solution of ammonium nitrate fertilizers of high nitrogen content
• Effective Date: 01-Apr-2026

oSIST prEN 17759:2026 is a CEN draft European Standard for measuring the pH of a solution made from ammonium nitrate fertilizers with high nitrogen content. It applies to fertilizing product blends where inorganic fertilizers are the largest component class, and it tells laboratories how to prepare the sample, calibrate the meter, perform the measurement, and report the result. The document sits in the fertilizers field and is prepared to replace CEN/TS 17759:2022.

What does oSIST prEN 17759:2026 specify?

oSIST prEN 17759:2026 specifies one laboratory method for determining the pH of a solution prepared from ammonium nitrate fertilizer of high nitrogen content. It is written for fertilizing product blends, so the user first has to confirm that this is the right standard for the blend being tested.

The scope matters because blend composition changes the choice of method. If inorganic fertilizers are not the largest component class in the blend, the standard for the highest-percentage component applies instead. If components are present in equal quantity, the user decides which standard to use.

Annex	What it covers
Annex A (informative)	Inter-laboratory study and statistical results used to support the precision statement.

The scope also notes that matrix interactions can affect analytical results in blends. In practice, that means the method is intended for routine use, but unusual formulations can still give unexpected behaviour and should be interpreted carefully.

What are the key requirements of oSIST prEN 17759:2026?

oSIST prEN 17759:2026 sets out a straightforward pH measurement workflow: prepare a solution from the sample, calibrate the pH meter, measure the clear liquid, and report the result in pH units. The most important point is that the method depends on good sample handling and stable measurement conditions.

• Clause 1 limits the method to the intended product type. The analyst must check whether the blend falls under the inorganic fertilizer category before using this procedure.
• Clause 2 makes sample preparation part of the method by reference to EN 1482-2. In practice, the sample has to be prepared in a standard way so that the result reflects the product, not the way it was handled.
• Clause 5 requires analytical-grade reagents and carbon dioxide-free water, and allows buffer solution A or B, or commercial pH standard solutions. This matters because contaminated water or unstable buffers can shift the pH reading.
• Clause 6 specifies the basic equipment: a pH meter with suitable electrodes, a graduated flask, a beaker, a balance and an airtight vessel. The method therefore assumes normal laboratory glassware and a meter that can give a stable reading.
• Clause 7 and Clause 8 cover sample handling and measurement. The sample must be representative, prepared according to EN 1482-2, then diluted, cleared of insolubles, and measured after calibration at the stated temperature. In practice, the analyst needs a clear solution and a stable signal before recording the result.
• Clause 9 requires reporting the pH result to one decimal place and stating the temperature used. That makes the result comparable with other laboratories and prevents ambiguity.
• Clause 10 and Annex A give the precision framework. The document uses inter-laboratory study data and states repeatability and reproducibility limits, so users can judge whether two results are close enough to agree.
• Clause 11 defines the minimum test report content. The report needs sample identification, the method reference, the result, sampling details if known, the analysis date, and any optional steps or incidents that could have influenced the result.

What terms does oSIST prEN 17759:2026 define?

oSIST prEN 17759:2026 uses the general fertilizer vocabulary from prEN 12944-1 and prEN 12944-2. These terms help the user classify the product correctly before testing.

• pH - the acidity or alkalinity value measured on the prepared solution.
• Buffer solution - a reference solution used to calibrate the pH meter before measurement.
• Fertilizing product blend - a mix of at least two component types, such as fertilizers, liming materials, soil improvers, growing media, inhibitors or plant biostimulants.
• Inorganic fertilizers - the product class that must be the highest-percentage class in the blend for this method to apply.
• Repeatability - agreement between two results from the same laboratory under the same conditions.
• Reproducibility - agreement between results from different laboratories under different conditions.
• Test report - the formal record of the sample, method, result and relevant operating details.

Who uses oSIST prEN 17759:2026?

oSIST prEN 17759:2026 is used by laboratories that test fertilizer products, especially where pH is part of product release, quality control or batch comparison. It is also useful to producers, buyers and technical staff who need a consistent pH result for a high-nitrogen ammonium nitrate blend.

The method supports routine analytical work on fertilizing product blends. It is particularly relevant when the product contains several component types and the user must decide which standard applies before testing.

What changed in oSIST prEN 17759:2026 from the previous edition?

oSIST prEN 17759:2026 will supersede CEN/TS 17759:2022. The foreword states these main changes:

• the Technical Specification has been adopted as a European Standard;
• the scope has been updated;
• the normative references have been updated;
• sampling and sample preparation have been updated;
• the nitrogen stream used during calibration and measurement has been removed;
• Clause 10 on precision has been added;
• Annex A with inter-laboratory study results has been added;
• the bibliography has been updated.

Which standards are used with oSIST prEN 17759:2026?

oSIST prEN 17759:2026 refers to several standards that support the method:

• EN 1482-2 - general sample preparation provisions used for preparing the test sample.
• prEN 12944-1 - general vocabulary for fertilizers, liming materials and inhibitors.
• prEN 12944-2 - fertilizer-specific vocabulary used with the terms and definitions clause.
• EN 1482-1 - recommended sampling method mentioned for obtaining a representative sample.
• ISO 5725-1 and ISO 5725-2 - the precision framework used for repeatability and reproducibility calculations.

What does the oSIST prEN 17759:2026 document contain?

oSIST prEN 17759:2026 contains clauses on scope, normative references, terms and definitions, principle, reagents, apparatus and equipment, sampling and sample preparation, procedure, expression of results, precision and test report. That structure shows the whole analytical workflow from sample handling to reporting.

The body of the document also includes the calibration step, the measurement step and the precision statement, so it is useful both for day-to-day laboratory work and for comparing results between laboratories. Annex A provides the inter-laboratory study and its statistical results, which support the precision data in the main text.

SLOVENSKI STANDARD
01-april-2026
Anorganska gnojila - Določanje pH-vrednosti raztopine gnojil iz amonijevega
nitrata z veliko vsebnostjo dušika
Inorganic fertilizers - Determination of pH of a solution of ammonium nitrate fertilizers of
high nitrogen content
Anorganische Düngemittel - Bestimmung des pH-Wertes in einer Lösung mit
Ammoniumnitratdüngemitteln mit hohem Stickstoffgehalt
Engrais inorganiques - Détermination du pH d'une solution d'engrais à base de nitrate
d'ammonium à forte teneur en azote
Ta slovenski standard je istoveten z: prEN 17759
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
prEN 17759
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2026
ICS 65.080 Will supersede CEN/TS 17759:2022
English Version
Inorganic fertilizers - Determination of pH of a solution of
ammonium nitrate fertilizers of high nitrogen content
Engrais inorganiques - Détermination du pH d'une Anorganische Düngemittel - Bestimmung des pH-
solution d'engrais à base de nitrate d'ammonium à Wertes in einer Lösung mit
forte teneur en azote Ammoniumnitratdüngemitteln mit hohem
Stickstoffgehalt
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 17759:2026 E
worldwide for CEN national Members.

prEN 17759:2026 (E)
Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Principle . 4
5 Reagents . 4
5.1 Distilled or demineralized water . 4
5.2 Buffer solution A . 4
6 Apparatus and equipment . 5
6.1 pH meter . 5
6.2 Graduated flask . 5
6.3 Beaker . 5
6.4 Balance . 5
6.5 Airtight vessel . 5
7 Sampling and sample preparation . 5
7.1 Sampling . 5
7.2 Sample preparation . 5
8 Procedure . 5
8.1 Calibration of the pH meter . 5
8.2 Determination . 5
9 Expression of the results . 5
10 Precision . 6
10.1 Inter-laboratory study . 6
10.2 Repeatability . 6
10.3 Reproducibility . 6
11 Test report . 6
Annex A (informative) Results of the inter-laboratory study . 7
A.1 Inter-laboratory study . 7
A.2 Statistical results . 7
Bibliography . 9

prEN 17759:2026 (E)
European foreword
This document (prEN 17759:2026) 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 will supersede CEN/TS 17759:2022.
prEN 17759:2026 includes the following significant technical changes with respect to
CEN/TS 17759:2022:
a) the CEN Technical Specification has been adopted as a European Standard;
b) update of Scope (Clause 1);
c) update of Normative references (Clause 2);
d) Sampling and sample preparation (Clause 7) has been updated;
e) the use of a nitrogen stream during calibration and measurement (8.1) has been removed;
f) Clause 10 (Precision) and Annex A including results of inter-laboratory study added;
g) update of Bibliography.
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 the
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