FprEN 13038
(Main)Soil improvers and growing media - Determination of electrical conductivity
General Information
- Abstract
This document specifies an instrumental method for the routine determination of electrical conductivity in a water extract of a soil improver or growing medium. The determination is carried out to obtain an indication of the content of water-soluble electrolytes in either soil improvers or growing media.
NOTE This method has been validated in an interlaboratory study with specific products that were present on the market during the study (as included in Annex A, being bark (Pinus pinaster, 20 mm to 40 mm fraction), coir pith (0 mm to 12 mm, washed and buffered), biowaste compost (Rottegrad 3), green compost (Rottegrad 5, 0 mm to 15 mm), liquid digestate, expanded clay, whole granules, 8 mm to 16 mm, growing media blend 1 (white peat, green compost, wood fibre, lime, inorganic fertilizer (NPK + micro elements)), growing media blend 2 (white peat, black peat, expanded perlite, lime, organic fertilizer) and growing media blend 3 (white peat, black peat, clay, inorganic fertilizer (NPK + micro elements))).
- Status
- Not Published
- Publication Date
- 06-Jan-2027
- Technical Committee
- CEN/TC 223 - Soil improvers and growing media
- Drafting Committee
- CEN/TC 223/WG 4 - Analytical methods
- Current Stage
- 4599 - Dispatch of FV draft to CMC - Finalization for Vote
- Start Date
- 27-Jul-2026
- Due Date
- 10-Jul-2023
- Completion Date
- 27-Jul-2026
- Mandate
- M/XXX - M/XXX
Overview
FprEN 13038: Soil improvers and growing media - Determination of electrical conductivity is a European standard developed by CEN that defines an instrumental method for routine measurement of electrical conductivity in water extracts from soil improvers or growing media. This standard provides a systematic approach for estimating the concentration of water-soluble electrolytes, which are important indicators of soil and growing media quality. The procedure is essential for manufacturers, quality control labs, and regulatory bodies to ensure compliance and product suitability, especially concerning the European Fertilizing Product Regulation.
Key Topics
- Measurement Principle: The method involves extracting a representative sample of soil improver or growing medium in water at controlled temperature, followed by measuring the electrical conductivity of the extract at 25°C. This reflects the total soluble salt content.
- Applicability: The standard applies to a wide range of materials, including bark, coir pith, composts, digestates, expanded clay, and growing media blends.
- Instrumentation: Utilizes a conductivity meter with automatic temperature correction to report results as millisiemens per metre (mS/m).
- Sampling and Preparation: The procedure specifies standardized sampling (referencing EN 12579) and sample preparation methods to ensure accuracy and repeatability.
- Validation: The method was validated through interlaboratory studies on several real-world materials, confirming its reliability and reproducibility as per ISO 5725-2.
Applications
The instrumental determination of electrical conductivity in soil improvers and growing media has significant practical value:
- Quality Control: Producers can monitor batch consistency and detect undesirably high levels of soluble salts, which could inhibit plant growth.
- Product Development: Helps in formulating new growing media blends by ensuring optimal levels of nutrients and salts.
- Certification and Compliance: Supports compliance with EU Regulation 2019/1009 on fertilizing products, which requires verifiable product properties for market placement.
- Research and Development: Facilitates academic and industrial research into substrate formulation and soil health by providing standardized, comparable data.
- Regulatory Inspections: Provides a harmonized protocol for public authorities to verify product quality on the market.
The method is suitable for a diversity of commercial materials, for example:
- Bark (Pinus pinaster), coir pith, biowaste and green compost, liquid digestate, expanded clay, and blends containing peat, compost, fertilizers, and other organic or inorganic components.
Related Standards
Several other standards and technical specifications complement FprEN 13038 for soil improvers and growing media:
- EN 12579:2024 - Soil improvers and growing media - Sampling
- prEN 13040-1:2025 - Sample preparation and laboratory bulk density determination for chemical/physical tests
- CEN/TS 17732:2022 - Soil improvers and growing media - Terminology
- EN 27888 (ISO 7888:1985) - Water quality - Determination of electrical conductivity
- ISO 5725-2 - Accuracy (trueness and precision) of measurement methods and results
Practical Value
The use of this standard ensures that:
- Results are reliable and comparable across laboratories and countries.
- Soil improvers and growing media meet defined quality benchmarks for horticultural and agricultural applications.
- Stakeholders throughout the supply chain, from manufacturers to end-users, can make informed decisions based on scientifically robust data.
By following FprEN 13038, organizations demonstrate commitment to high-quality products, customer satisfaction, and regulatory compliance in the European market for soil improvers and growing media.
Relations
- Effective Date
- 19-Jan-2023
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Frequently Asked Questions
FprEN 13038 is a draft published by the European Committee for Standardization (CEN). Its full title is "Soil improvers and growing media - Determination of electrical conductivity". This standard covers: This document specifies an instrumental method for the routine determination of electrical conductivity in a water extract of a soil improver or growing medium. The determination is carried out to obtain an indication of the content of water-soluble electrolytes in either soil improvers or growing media. NOTE This method has been validated in an interlaboratory study with specific products that were present on the market during the study (as included in Annex A, being bark (Pinus pinaster, 20 mm to 40 mm fraction), coir pith (0 mm to 12 mm, washed and buffered), biowaste compost (Rottegrad 3), green compost (Rottegrad 5, 0 mm to 15 mm), liquid digestate, expanded clay, whole granules, 8 mm to 16 mm, growing media blend 1 (white peat, green compost, wood fibre, lime, inorganic fertilizer (NPK + micro elements)), growing media blend 2 (white peat, black peat, expanded perlite, lime, organic fertilizer) and growing media blend 3 (white peat, black peat, clay, inorganic fertilizer (NPK + micro elements))).
This document specifies an instrumental method for the routine determination of electrical conductivity in a water extract of a soil improver or growing medium. The determination is carried out to obtain an indication of the content of water-soluble electrolytes in either soil improvers or growing media. NOTE This method has been validated in an interlaboratory study with specific products that were present on the market during the study (as included in Annex A, being bark (Pinus pinaster, 20 mm to 40 mm fraction), coir pith (0 mm to 12 mm, washed and buffered), biowaste compost (Rottegrad 3), green compost (Rottegrad 5, 0 mm to 15 mm), liquid digestate, expanded clay, whole granules, 8 mm to 16 mm, growing media blend 1 (white peat, green compost, wood fibre, lime, inorganic fertilizer (NPK + micro elements)), growing media blend 2 (white peat, black peat, expanded perlite, lime, organic fertilizer) and growing media blend 3 (white peat, black peat, clay, inorganic fertilizer (NPK + micro elements))).
FprEN 13038 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 13038 has the following relationships with other standards: It is inter standard links to EN 13038:2011. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
FprEN 13038 is associated with the following European legislation: EU Directives/Regulations: 2019/1009; Standardization Mandates: M/564, M/564 AMD 1, M/564 AMD 2, M/XXX. 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 13038 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-november-2025
Izboljševalci tal in rastni substrati - Določanje električne prevodnosti
Soil improvers and growing media - Determination of electrical conductivity
Bodenverbesserungsmittel und Kultursubstrate - Bestimmung der elektrischen
Leitfähigkeit
Amendements du sol et supports de culture - Détermination de la conductivité électrique
Ta slovenski standard je istoveten z: prEN 13038
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
DRAFT
EUROPEAN STANDARD
prEN 13038
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2025
ICS 65.080 Will supersede EN 13038:2011
English Version
Soil improvers and growing media - Determination of
electrical conductivity
Amendements du sol et supports de culture - Bodenverbesserungsmittel und Kultursubstrate -
Détermination de la conductivité électrique Bestimmung der elektrischen Leitfähigkeit
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 223.
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 13038:2025 E
worldwide for CEN national Members.
prEN 13038:2025 (E)
Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Principle . 4
5 Reagents . 4
6 Apparatus . 5
7 Sampling . 5
8 Preparation . 5
9 Procedure . 5
9.1 Extraction of materials in solid form . 5
9.2 Extraction of material in pre-shaped form . 6
9.3 Extraction of liquid or pasty materials . 6
9.4 Filtration . 6
9.5 Measuring conductivity of the potassium chloride solutions . 6
9.6 Measurement of the specific electrical conductivity of the filtrates . 6
10 Test report . 7
11 Validation of the method . 7
11.1 Validation in accordance with ISO 5725-2. 7
11.2 Performance characteristics. 7
Annex A (informative) Performance characteristics of the method . 8
Bibliography . 10
prEN 13038:2025 (E)
European foreword
This document (prEN 13038:2025) has been prepared by Technical Committee CEN/TC 223 “Soil
improvers and growing media”, the secretariat of which is held by NEN.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 13038:2011.
prEN 13038:2025 includes the following significant technical changes with respect to EN 13038:2011:
— adaption of scope and applicability with respect to the EU-Fertilizer Product Regulation [3].
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.
prEN 13038:2025 (E)
1 Scope
This document specifies an instrumental method for the routine determination of electrical conductivity
in a water extract of a soil improver or growing medium. The determination is carried out to obtain an
indication of the content of water soluble electrolytes in either soil improvers or growing media.
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.
CEN/TS 17732:2022, Soil improvers and growing media – Terminology
EN 12579:2024, Soil improvers and growing media - Sampling
prEN 13040-1:2025, Soil improvers and growing media — Sample preparation — Part 1: Sample
preparation for chemical and physical tests, determination of dry matter content, moisture content and
laboratory bulk density
3 Terms and definitions
For the purposes of this document, the terms and definitions given in CEN/TS 17732:2022 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
electrical conductivity
ability of an aqueous extract of the sample to conduct electricity as a function of the ion concentration
4 Principle
A sample is extracted with water at 22 °C ± 3,0 °C in an extraction ratio of 1 to 5 (1 V sample + 5 V water)
to dissolve the electrolytes. The specific electrical conductivity of the extract is measured and the result
is adjusted to a measurement temperature of 25 °C.
5 Reagents
5.1 Water, having an electrical conductivity not higher than 0,2 mS/m at 25 °C.
5.2 Potassium chloride solution, c(KCl) = 0,100 mol/l.
Dissolve 7,456 g potassium chloride (KCl), previously dried for 2 h at 105 °C, in water (5.1) and dilute to
1 000 ml. The specific electrical conductivity of this solution at 25 °C is 1 290 mS/m.
5.3 Potassium chloride solution, c(KCl) = 0,0100 mol/l.
Add 100,0 ml of potassium chloride solution (5.2) into a 1 000 ml volumetric flask and dilute to the
1 000 ml mark with water (5.1) at 20 °C. The specific electrical conductivity of this solution at 25 °C is
141 mS/m.
...