oSIST prEN 13039:2025
(Main)Soil improvers and growing media - Determination of organic matter content and ash
- Abstract
This document specifies a routine method for determining the organic matter and the ash content of soil improvers and growing media.
NOTE 1 The loss on ignition (LOI) is often used as an estimate for the content of organic matter in the sample. Inorganic substances or decomposition products (e.g. H2O, CO2, SO2, O2) are released or absorbed and some inorganic substances are volatile under the reaction conditions. Thus, a conversion to the organic carbon content is not possible.
NOTE 2 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), green compost (Rottegrad 5,0 mm to 15 mm), liquid digestate, mineral wool, soil improver (pellets, sieved 4 mm) and growing media blend (white peat, black peat, expanded perlite, lime, organic fertilizer)).
- Status
- Not Published
- Public Enquiry End Date
- 01-Dec-2025
- Technical Committee
- KAT - Soil quality
- Current Stage
- 4020 - Public enquire (PE) (Adopted Project)
- Start Date
- 08-Oct-2025
- Due Date
- 25-Feb-2026
- Completion Date
- 15-Dec-2025
- Mandate
- M/XXX - M/XXX
oSIST prEN 13039:2025 is the Slovene standard identical to draft European Standard prEN 13039:2025, published by SIST and prepared in CEN/TC 223. It specifies a routine method for determining organic matter content and ash in soil improvers and growing media. The method uses drying and ignition, and reports results as a percentage by mass of the dried sample.
What does oSIST prEN 13039:2025 specify?
oSIST prEN 13039:2025 specifies a routine laboratory method for soil improvers and growing media. It is used to determine both organic matter and ash content by controlled drying and burning.
The document notes that loss on ignition (LOI) is often used as an estimate of organic matter, but it is only an empirical parameter. Because inorganic substances and decomposition products can be released or absorbed during heating, LOI cannot be converted to organic carbon content.
The document is organized into Clauses 1 to 10 and one informative annex.
| Annex | What it covers |
|---|---|
| Annex A | Performance characteristics of the method, based on an interlaboratory study |
Clause 6 states that sampling is not part of the method itself. Clause 10 covers validation of the method and the performance data reported in Annex A.
What are the key requirements of oSIST prEN 13039:2025?
oSIST prEN 13039:2025 is built around a simple gravimetric sequence: dry the sample, ignite it, and calculate the mass loss and residue. In practice, this means the operator needs controlled temperatures, repeat weighing, and a representative prepared sample.
Principle and measurement basis
Clause 4 states that the test portion is dried at 105 °C ± 2 °C and then ashed at 550 °C ± 25 °C. The ash is the residue after ignition, and organic matter is taken as the loss of mass on ignition.
The results are expressed as percentages by mass of the dried sample. That matters because results from different materials can be compared only when the same dry basis is used.
Apparatus and handling
Clause 5 requires a drying oven, an electric muffle furnace, a shallow basin, a desiccator, and an analytical balance with a 0.01 g scale interval. The basin may be made of fused silica, quartz or platinum, and must be dry and free of relevant volatile substances.
For practical use, the equipment has to hold temperature within the stated limits. Small weighing errors or unstable heating will directly affect the reported organic matter and ash values.
Sampling and sample preparation
Clause 6 says sampling follows EN 12579:2024, and the laboratory should receive a representative sample that has not been damaged or changed during transport or storage. Clause 7.2 requires sample preparation in accordance with Clause 10 of prEN 13040-1:2025.
This means the result depends not only on the test itself, but also on how the sample was taken, transported and prepared before the ignition step.
Test procedure and endpoint
Clause 7.3 gives the step-by-step determination. The sample is dried in the oven for at least 4 h, cooled in a desiccator, and weighed. It is then heated in the muffle furnace through a staged rise to 550 °C and held there, cooled, and weighed again.
If the difference between repeated ash weighings is above 0.01 g, the ashing step is repeated. In practice, the operator is looking for a stable final mass before accepting the ash result.
Reporting and validation
Clause 9 requires the test report to identify the sample, cite this document by year, state the results to one decimal place, and record unusual observations or any non-standard operation. Clause 10 states that the method was validated in accordance with ISO 5725-2, and Annex A gives the performance characteristics.
That helps users judge whether the method is suitable for routine control and how much variability to expect between laboratories.
What terms does oSIST prEN 13039:2025 define?
- Organic matter - the carbon fraction of a sample that is free from water and inorganic substances.
- Ash - the residual mineral matter remaining after controlled burning destroys the organic matter or material.
- Loss on ignition (LOI) - the mass lost when the dried sample is heated and burned, used here as an estimate of organic matter.
- Dry matter (DM) - the dried sample basis on which the organic matter and ash results are expressed.
- Test sample - the prepared sample portion used for the actual drying and ignition determination.
Who uses oSIST prEN 13039:2025?
oSIST prEN 13039:2025 is used by testing laboratories, manufacturers, and quality-control teams working with soil improvers and growing media. It is also relevant to technical staff who need a repeatable method for product specification checks, incoming inspection, and routine batch control in the fertilizers and growing media sector.
Because the document gives a common calculation basis and a defined test sequence, it is useful when different sites or laboratories need comparable results.
What changed in oSIST prEN 13039:2025 from the previous edition?
oSIST prEN 13039:2025 will supersede EN 13039:2011. The European foreword states two significant technical changes: the scope has been adapted, and the temperature range for drying has been expanded.
Which standards are used with oSIST prEN 13039:2025?
- CEN/TS 17732:2022 - provides the terminology used for soil improvers and growing media.
- EN 12579:2024 - covers sampling for soil improvers and growing media.
- prEN 13040-1:2025 - gives sample preparation for chemical and physical tests, including dry matter content and moisture content.
- ISO 5725-2 - provides the basis used for method validation and the repeatability and reproducibility statistics.
What does the oSIST prEN 13039:2025 document contain?
The document contains the scope, normative references, terms and definitions, principle, apparatus, sampling direction, procedure, calculation, test report requirements, and validation of the method. It also includes a short safety note for dusty or sharp samples.
Annex A presents the interlaboratory study behind the performance characteristics. It lists the tested materials, including bark, green compost, liquid digestate, mineral wool, a soil improver in pellets, and a growing media blend, and gives the statistical data for organic matter and ash content.
Relations
- Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
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Frequently Asked Questions
oSIST prEN 13039:2025 is a draft published by the Slovenian Institute for Standardization (SIST). Its full title is "Soil improvers and growing media - Determination of organic matter content and ash". This standard covers: This document specifies a routine method for determining the organic matter and the ash content of soil improvers and growing media. NOTE 1 The loss on ignition (LOI) is often used as an estimate for the content of organic matter in the sample. Inorganic substances or decomposition products (e.g. H2O, CO2, SO2, O2) are released or absorbed and some inorganic substances are volatile under the reaction conditions. Thus, a conversion to the organic carbon content is not possible. NOTE 2 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), green compost (Rottegrad 5,0 mm to 15 mm), liquid digestate, mineral wool, soil improver (pellets, sieved 4 mm) and growing media blend (white peat, black peat, expanded perlite, lime, organic fertilizer)).
This document specifies a routine method for determining the organic matter and the ash content of soil improvers and growing media. NOTE 1 The loss on ignition (LOI) is often used as an estimate for the content of organic matter in the sample. Inorganic substances or decomposition products (e.g. H2O, CO2, SO2, O2) are released or absorbed and some inorganic substances are volatile under the reaction conditions. Thus, a conversion to the organic carbon content is not possible. NOTE 2 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), green compost (Rottegrad 5,0 mm to 15 mm), liquid digestate, mineral wool, soil improver (pellets, sieved 4 mm) and growing media blend (white peat, black peat, expanded perlite, lime, organic fertilizer)).
oSIST prEN 13039:2025 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.
oSIST prEN 13039:2025 has the following relationships with other standards: It is inter standard links to SIST EN ISO 13161:2021, SIST-TP CEN ISO/TR 22930-1:2021, SIST EN ISO 22125-2:2020, SIST-TP CEN ISO/TR 22930-2:2021, SIST EN ISO 23548:2025, SIST EN ISO 11665-6:2020, SIST EN ISO 18589-1:2021, SIST EN ISO 13165-3:2025, SIST EN ISO 20044:2024, SIST EN ISO 18589-5:2021, SIST EN ISO 13160:2021, SIST EN ISO 19581:2025, SIST EN ISO 11665-5:2020, SIST EN ISO 13165-2:2023, SIST EN ISO 13162:2021. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
oSIST prEN 13039:2025 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.
oSIST prEN 13039:2025 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 organske snovi in pepela
Soil improvers and growing media - Determination of organic matter content and ash
Bodenverbesserungsmittel und Kultursubstrate - Bestimmung des Gehaltes an
organischer Substanz und Asche
Amendements du sol et supports de culture - Détermination de la teneur en matière
organique et des cendres
Ta slovenski standard je istoveten z: prEN 13039
ICS:
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
DRAFT
EUROPEAN STANDARD
prEN 13039
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2025
ICS 65.080 Will supersede EN 13039:2011
English Version
Soil improvers and growing media - Determination of
organic matter content and ash
Amendements du sol et supports de culture - Bodenverbesserungsmittel und Kultursubstrate -
Détermination de la teneur en matière organique et Bestimmung des Gehaltes an organischer Substanz und
des cendres Asche
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 13039:2025 E
worldwide for CEN national Members.
prEN 13039:2025 (E)
Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Principle . 4
5 Apparatus . 5
6 Sampling . 5
7 Procedure . 5
7.1 Safety . 5
7.2 Test sample . 5
7.3 Determination . 5
8 Calculation and expression of results . 6
9 Test report . 6
10 Validation of the method . 6
10.1 Validation in accordance with ISO 5725-2. 6
10.2 Performance characteristics. 6
Annex A (informative) Performance characteristics of the method . 7
Bibliography . 10
prEN 13039:2025 (E)
European foreword
This document (prEN 13039:2025) 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 13039:2011.
prEN 13039:2025 includes the following significant technical changes with respect to EN 13039:2011:
— the scope has been adapted.
— the temperature range for the drying has been expanded.
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 13039:2025 (E)
1 Scope
This document specifies a routine method for determining the organic matter and the ash content of soil
improvers and growing media.
NOTE The loss on ignition (LOI) is often used as an estimate for the content of organic matter in the sample.
Inorganic substances or decomposition products (e.g. H O, CO , SO , O ) are released or absorbed and some
2 2 2 2
inorganic substances are volatile under the reaction conditions. Thus, a conversion to the organic carbon content is
not possible.
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
organic matter
carbon fraction of a sample which is free from water and inorganic substances
3.2
ash
residual mineral matter remaining after the destruction of organic matter/material by controlled burning
4 Principle
The test portion is dried at 105 °C ± 2 °C, then ashed at 550 °C ± 25 °C. The ash is determined as the
residue on ignition. The organic matter is taken to be the loss of mass on ignition. Both are expressed as
a percentage by mass of the dried sample.
NOTE 1 Loss on ignition (LOI) is an empirical parameter, thus in principle there is no interference connected to
the determination. However, for some purposes the determination of LO
...