SIST EN 17721:2025
(Main)Plant biostimulants - Determination of the pH for liquid microbial plant biostimulants/pH in microbial products - Determination of pH
Plant biostimulants - Determination of the pH for liquid microbial plant biostimulants/pH in microbial products - Determination of pH
This European Standard establishes the methodology for the determination of pH in plant biostimulant products in accordance to the Regulation of EU fertilising products.
Pflanzen-Biostimulanzien - Bestimmung des pH-Wertes für flüssige mikrobielle Pflanzen-Biostimulanzien/pH-Wert in mikrobiellen Produkten - Bestimmung des pH-Wertes
Dieses Dokument legt ein Verfahren zur Messung des pH Wertes in flüssigen mikrobiellen Pflanzen-Biostimulanzien im Labor unter Verwendung von pH Elektroden mit einer Glasmembran fest.
Andere Pflanzen-Biostimulanzien als mikrobielle Pflanzen-Biostimulanzien gehören nicht zum Anwendungsbereich dieses Dokuments, da die Verordnung [1] keine grundlegenden Anforderungen hinsichtlich der Messung des pH Wertes von nicht-mikrobiellen Pflanzen-Biostimulanzien enthält.
Biostimulants des végétaux - Détermination du pH des biostimulants microbiens liquides des végétaux/pH dans les produits microbiens - Détermination du pH
Le présent document spécifie une méthode de mesure en laboratoire de la valeur du pH dans les biostimulants microbiens des végétaux sous forme liquide, à l’aide d’électrodes de pH avec une membrane en verre.
Les biostimulants des végétaux autres que les biostimulants microbiens des végétaux sont exclus du domaine d’application du présent document, car il n’existe pas d’exigence essentielle dans le Règlement [1] de mesure du pH des biostimulants des végétaux non microbiens.
Rastlinski biostimulanti - Določanje pH-vrednosti za tekoče mikrobne biostimulante/mikrobne proizvode - Določanje pH-vrednosti
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-februar-2025
Nadomešča:
SIST-TS CEN/TS 17721:2023
Rastlinski biostimulanti - Določanje pH-vrednosti za tekoče mikrobne
biostimulante/mikrobne proizvode - Določanje pH-vrednosti
Plant biostimulants - Determination of the pH for liquid microbial plant biostimulants/pH in
microbial products - Determination of pH
Pflanzen-Biostimulanzien - Bestimmung des pH-Wertes für flüssige mikrobielle Pflanzen-
Biostimulanzien/pH-Wert in mikrobiellen Produkten - Bestimmung des pH-Wertes
Biostimulants des végétaux - Détermination du pH des biostimulants microbiens liquides
des végétaux/pH dans les produits microbiens - Détermination du pH
Ta slovenski standard je istoveten z: EN 17721:2024
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN 17721
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2024
EUROPÄISCHE NORM
ICS 65.080 Supersedes CEN/TS 17721:2022
English Version
Plant biostimulants - Determination of the pH for liquid
microbial plant biostimulants/pH in microbial products -
Determination of pH
Biostimulants des végétaux - Détermination du pH des Pflanzen-Biostimulanzien - Bestimmung des pH-
biostimulants microbiens liquides des végétaux/pH Wertes für flüssige mikrobielle Pflanzen-
dans les produits microbiens - Détermination du pH Biostimulanzien/pH-Wert in mikrobiellen Produkten -
Bestimmung des pH-Wertes
This European Standard was approved by CEN on 26 August 2024.
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. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists 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.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 17721:2024 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 Principle . 9
5 Apparatus and materials . 9
6 Sampling . 11
7 Procedure. 12
8 Evaluation . 13
9 Precision . 13
10 Test report . 13
Annex A (informative) Repeatability and reproducibility data . 15
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. 18
Bibliography . 19
European foreword
This document (EN 17721:2024) has been prepared by Technical Committee CEN/TC 455 “Plant
Biostimulants”, the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by May 2024, and conflicting national standards shall be
withdrawn at the latest by May 2024.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes CEN/TS 17721:2022.
— the European foreword and the Introduction have been updated;
— Clause 2, Normative references, has been updated;
— in Clause 3.2, the formula has been revised;
— in Clause 3.10, the definition of pH glass membrane has been revised;
— in Clause 5.5, the description of pH electrode has been revised;
— in Clause 10, Test Report, the list has been revised;
— Annex A on repeatability and reproducibility data has been added;
— Annex ZA has been added;
— the Bibliography has been revised.
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 relationship with EU Legislation, see informative Annex ZA, which is an integral part of this
document.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: 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 the United
Kingdom.
Introduction
The European Committee for Standardization (CEN) was requested by the European Commission (EC) to
draft European Standards or European Standardization deliverables to support the implementation of
Regulation (EU) 2019/1009 of 5 June 2019 [1] laying down rules on the making available on the market
of EU fertilising products (“FPR” or “Fertilising Products Regulation”).
This standardization request, presented as SR M/564 and relevant amendments, also contributes to the
Communication on “Innovating for Sustainable Growth: A Bio economy for Europe”. The interest in plant
biostimulants has increased significantly in Europe as a valuable tool to use in agriculture.
Standardization was identified as having an important role in order to promote the use of biostimulants.
The work of CEN/TC 455 seeks to improve the reliability of the supply chain, thereby improving the
confidence of farmers, industry, and consumers in biostimulants, and will promote and support
commercialisation of the European biostimulant industry.
WARNING — Persons using this document should be familiar with normal laboratory practice. This
document does not purport to address all of the safety problems, if any, associated with its use. It is the
responsibility of the user to establish appropriate safety and health practices and to ensure compliance
with any national regulatory conditions.
IMPORTANT — It is absolutely essential that tests conducted in accordance with this document be
carried out by suitably trained staff.
1 Scope
This document specifies a method for laboratory measurement of the pH value in liquid microbial plant
biostimulants, using pH electrodes with a glass membrane.
This document does not apply to plant biostimulants other than microbial plant biostimulants.
This document is applicable to the blends of fertilizing products where a blend is a mix of at least two of
the following component EU fertilising products categories: Fertilizers, Liming Materials, Soil Improvers,
Growing Media, Plant Biostimulants and where the following category Plant Biostimulants is the highest
percentage in the blend by mass or volume, or in the case of liquid form by dry mass. If Plant
Biostimulants is not the highest percentage in the blend, the European Standard for the highest
percentage of the blend applies. In case a blend of fertilizing products is composed of components in equal
quantity or in case the component EU fertilising products used for the blend have identical formulations ,
the user decides which standard to apply.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN 17702-1:2024, Plant biostimulants — Sampling and sample preparation — Part 1: Sampling
EN 17702-2:2024, Plant biostimulants — Sampling and sample preparation — Part 2: Sample preparation
EN 17724:2024, Plant biostimulants — Terminology
EN ISO 3696:1995, Water for analytical laboratory use — Specification and test methods (ISO 3696:1987)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 17724:2024 and the following
apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
• ISO Online browsing platform: available at https://www.iso.org/obp
• IEC Electropedia: available at https://www.electropedia.org/
3.1
pH
measure for the acidic or basic reaction of an aqueous solution or dispersion
Note 1 to entry: Notation of pH: the p and the H are vertically on one line.
Note 2 to entry: The acidic reaction is determined by the activity of the existing hydrogen ions. The basic reaction
is determined by the activity of the existing hydroxide ions. The direct relationship between the activities of the
hydrogen ions and the hydroxide ions is described by the ionic product of the water.
An example of such a blend is a product with 2 claimed functions consisting of a non-microbial plant biostimulant
and an organic fertilizer composed of 1 kg/kg of plant biostimulant from seaweed.
3.2
pH value
decadal logarithm of the hydrogen ion activity multiplied with (−1)
m ⋅γ
a
+ +
+
H m,H
H
pH=pa =−lg =−lg
+
H
mm
00
With
a m⋅γ where
+ ++
H H mH,
+ is the activity of the hydrogen ion, expressed in mole per kilogram (mol/kg);
a
H
m is the standard molality expressed in mole per kilogram (mol/kg);
+ is the activity coefficient of the hydrogen ion;
γ
m,H
+ is the molality of the hydrogen ion, expressed in mole per kilogram (mol/kg).
m
H
Note 1 to entry: The pH value is not measurable as a measure of a single ion activity. Therefore, pH(PS) values of
solutions of primary reference material (PS, en: Primary Standard) are determined, which are approximated to it
and can be attributed to it. This is based on a worldwide agreement; see EN ISO 80000-9:2019, Annex C [2].
3.3
potentiometric measuring chain
combination of electrochemical half cells
3.4
pH combination electrode
pH single-rod measuring chain
potentiometric measuring chain (3.3) providing a voltage which depends on the pH value (3.2) of the
measuring solution
Note 1 to entry: One of the two electrochemical half cells is the pH measuring electrode, the second is a reference
electrode (3.5) (see Figure 1).
Note 2 to entry: An integrated temperature sensor is recommended (see Figure 1).
=
Key
1 reference electrode, consisting in 2, 3 and 4
2 reference element
3 reference electrolyte
4 diaphragm
5 pH measuring electrode, consisting of 6, 7 and 8
6 reference element
7 glass membrane
8 internal buffer
9 temperature sensor
U pH proportional voltage
Figure 1 — Design of a pH electrode with glass membrane and temperature sensor (schematic
illustration)
Note 3 to entry: This document refers to pH electrodes with glass membranes. The electrode shaft should be made
of material resistant to chemicals and solvents.
3.5
reference electrode
electrode providing a constant potential which is independent from the pH value (3.2) of the measuring
medium
Note 1 to entry: At present, the most commonly used type is the silver/silver chloride reference electrode, whose
pot
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.