FprEN 15961

• Abstract:

  This document specifies a method for the extraction of water-soluble calcium, magnesium, sodium and sulfur in the form of sulfates, so that the same extract can be used for the determination of each nutrient required.; This document is applicable to inorganic fertilizers.

• Status: Not Published
• Publication Date: 13-Jan-2027
• ICS: 65.080 - Fertilizers
• 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: 24-Sep-2026
• Due Date: 12-Mar-2027
• Completion Date: 24-Sep-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: kSIST FprEN 15961:2026 - Inorganic fertilizers - Extraction of water-soluble calcium, magnesium, sodium and sulfur in the form of sulfates

• Revises: EN 15961:2017 - Fertilizers - Extraction of water-soluble calcium, magnesium, sodium and sulfur in the form of sulfates
• Effective Date: 02-Apr-2025

FprEN 15961 is a CEN draft European Standard for inorganic fertilizers. It specifies a water extraction method for calcium, magnesium, sodium and sulfur in the form of sulfates, so the same extract can be used for determining each nutrient required. Laboratories, fertilizer producers and buyers use it when they need a common preparation step for analysis of inorganic fertilizer samples.

What does FprEN 15961 specify?

FprEN 15961 specifies the scope of a laboratory extraction method for inorganic fertilizers and the structure of the document that describes it. Clause 1 states the field of application, while Clauses 2 to 9 cover references, terms, principle, sampling and sample preparation, reagents, apparatus, procedure and reporting, followed by a bibliography.

The method is for extracting water-soluble calcium, magnesium, sodium and sulfur present in the form of sulfates. In practice, that means the document is about preparing one aqueous extract that can then be used for the separate nutrient determinations needed in a fertilizer laboratory.

What are the key requirements of FprEN 15961?

Extraction principle

FprEN 15961 bases the method on boiling the fertilizer in water under specified conditions to extract calcium, magnesium, sodium and sulfur as sulfates. This matters because the analyst must prepare a solution that represents the water-soluble fraction, not the total nutrient content.

Sampling and sample preparation

FprEN 15961 says sampling is not part of the method itself, and it points users to EN 1482-1 and EN 1482-3 for recommended sampling approaches. Clause 5 also requires sample preparation to follow EN 1482-2, and it recommends grinding the laboratory sample for homogeneity. In practice, the quality of the result depends on starting with a representative and well-prepared sample.

Reagents and water quality

FprEN 15961 requires distilled or demineralized water, with electrical conductivity of less than 0.5 mS/m at 25 °C. That limit matters because the water itself must not add measurable calcium, magnesium, sodium or sulfur contamination to the extract.

Apparatus

FprEN 15961 specifies standard laboratory equipment, an adjustable electric hot plate, a 600 ml beaker, a 500 ml graduated flask and dry low-magnesium filter paper with medium porosity and filtration rate. These items define the extraction and filtration setup, so the laboratory can reproduce the method in a controlled way.

Test portion and extraction procedure

FprEN 15961 sets different test portions depending on the sulfur and calcium content of the fertilizer. The method then adds about 400 ml of water, boils for 30 minutes with a lid, cools and stands the mixture for 24 hours at room temperature, then decants, makes up to volume and filters the solution. The first filtrate portions are discarded, and the final filtrate must be completely transparent. In practice, these steps control completeness of extraction and the clarity of the solution used for later determinations.

Test report

FprEN 15961 requires the test report to identify the sample, state the method used with the document year, record the sampling date and procedure if known, give the date the extraction finished, and list any optional details or incidents that may have affected the result. This supports traceability, comparison of results and review of any unusual laboratory event.

What terms does FprEN 15961 define?

• CEN - The European Committee for Standardization, which prepared this draft European Standard.
• EN - A European Standard; in this document, EN references are the standards used for sampling, sample preparation and vocabulary.
• Laboratory sample - The sample received and prepared for analysis after sampling and transport.
• Test portion - The weighed amount of sample taken for the extraction procedure.
• Filtrate - The liquid that passes through the filter after extraction.
• Inorganic fertilizers - The product group to which this extraction method applies.
• Water-soluble - The fraction that is extracted into water under the method conditions.

Who uses FprEN 15961?

FprEN 15961 is used by fertilizer testing laboratories, quality control teams in fertilizer production, and buyers or specifiers who need analytical confirmation of nutrient availability. It is also relevant to technical staff who prepare samples, run wet chemistry extractions and document test results for product control or conformity assessment.

What changed in FprEN 15961 from the previous edition?

FprEN 15961 will supersede EN 15961:2017. The foreword also lists these significant technical changes with respect to EN 15925:2017: deletion of the reference to Regulation (EC) No 2003/2003 in the scope, and updates to the normative references and bibliography.

Which standards are used with FprEN 15961?

Standard	What it contributes
EN 1482-2	General sample preparation provisions used for preparing the laboratory sample.
EN 12944-1	General fertilizer and liming material vocabulary used for the terms and definitions clause.
EN 12944-2	Fertilizer-specific vocabulary used with the terms and definitions clause.
EN 1482-1	Recommended general sampling provisions mentioned in Clause 5.
EN 1482-3	Recommended sampling of static heaps mentioned in Clause 5.

What does the FprEN 15961 document contain?

FprEN 15961 contains a short laboratory method focused on one extraction step, not a full nutrient determination method. Its main body covers the principle, sampling and sample preparation, reagents, apparatus, procedure and reporting, so users can prepare a suitable extract for later analysis.

Clause 8 gives the practical workflow: choose the test portion, boil it in water, cool and stand it, decant, make up to volume and filter. Clause 9 then tells the user what must be recorded in the report so the result can be traced and reviewed.

The bibliography points to the sampling standards that support the method in practice.

SLOVENSKI STANDARD
oSIST prEN 15961:2026
01-februar-2026
Anorganska gnojila - Ekstrakcija v vodi topnega kalcija, magnezija in natrija ter
žvepla v obliki sulfata
Inorganic fertilizers - Extraction of water-soluble calcium, magnesium, sodium and sulfur
in the form of sulfates
Anorganische Düngemittel - Extraktion von wasserlöslichem Calcium, Magnesium und
Natrium sowie von Schwefel in Form von Sulfat
Engrais inorganiques - Extraction du calcium, du magnésium, du sodium et du soufre
solubles dans l’eau sous la forme de sulfates
Ta slovenski standard je istoveten z: prEN 15961
ICS:
65.080 Gnojila Fertilizers
oSIST prEN 15961:2026 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN 15961:2026
oSIST prEN 15961:2026
DRAFT
EUROPEAN STANDARD
prEN 15961
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2025
ICS 65.080 Will supersede EN 15961:2017
English Version
Inorganic fertilizers - Extraction of water-soluble calcium,
magnesium, sodium and sulfur in the form of sulfates
Engrais inorganiques - Extraction du calcium, du Anorganische Düngemittel - Extraktion von
magnésium, du sodium et du soufre solubles dans l'eau wasserlöslichem Calcium, Magnesium und Natrium
sous la forme de sulfates sowie von Schwefel in Form von Sulfat
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
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 15961:2025 E
worldwide for CEN national Members.

oSIST prEN 15961:2026
prEN 15961:2025 (E)
Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Principle . 4
5 Sampling and sample preparation . 4
6 Reagents . 4
7 Apparatus . 5
8 Procedure . 5
8.1 Test portion . 5
8.2 Preparation of the solution . 5
9 Test report . 5
Bibliography .
...