EN 13266:2001

Slow-release fertilizers - Determination of the release of the nutrients - Method for coated fertilizers

This European Standard specifies a method for the determination of the slow release properties of nutrients from coated fertilizers. pH-dependent hydrolysis and degradation by biological or microbial mechanisms are excluded.
The specified method is only applicable to products releasing any nutrients by means of a non-biological process (i.e. those where the nutrients are released by a physical mechanism). Microbial attack on the coating (e.g. sulfur coated fertilizers) and the consequences thereof are not measurable by the technique described.
This method involves a lengthy process which may not be appropriate for day to day testing purposes. Accelerated methods may be used provided they are correlated with this standard. An example of such an accelerated method is described in annex B. Regression analysis may also be used for this purpose.

Langsam freisetzende Düngemittel - Bestimmung der Freisetzungsrate von Nährstoffen - Verfahren für umhüllte Düngemittel

Diese Europäische Norm legt ein Verfahren zur Bestimmung der Eigenschaften von Nährstoffen hinsichtlich deren langsamer Freisetzung aus umhüllten Düngemitteln fest. Davon ausgenommen sind die pH-abhängige Hydrolyse und der Abbau durch biologische oder mikrobielle Mechanismen.
Das festgelegte Verfahren gilt nur für Produkte, bei denen die Freisetzung der Nährstoffe durch einen nicht-biologischen Vorgang erfolgt (d. h. solche, bei denen die Nährstoffe durch einen physikalischen Mechanismus freigesetzt werden). Ein mikrobieller Angriff der Umhüllung (z. B. schwefelumhüllte Düngemittel) und die daraus folgenden Konsequenzen sind mit der beschriebenen Technik nicht messbar.
Das beschriebene Verfahren umfasst einen sehr langwierigen Vorgang, der für alltägliche Prüfzwecke ungeeignet sein kann. Schnellverfahren dürfen angewendet werden, sofern sichergestellt ist, dass diese mit der vorliegenden Norm korrelieren. Ein Beispiel für solch ein Schnellverfahren ist in Anhang B beschrieben. Ebenso darf zu diesem Zweck eine Regressionsanalyse angewandt werden.

Engrais à libération lente - Détermination du mode de libération des éléments nutritifs - Méthode applicable aux engrais enrobés

La présente Norme européenne spécifie une méthode d'identification et de détermination des propriétés de libération lente d'éléments nutritifs contenus dans les engrais enrobés. L'hydrolyse en fonction du pH et la dégradation par des mécanismes biologiques ou microbiens sont exclues.
La méthode spécifiée s'applique uniquement aux produits libérant des éléments nutritifs au moyen d'un procédé non-biologique (enrobage s'effectuant par un mécanisme physique) ; la technique décrite ne permet pas de mesurer l'attaque microbienne subie par l'enrobage (par exemple dans le cas des engrais enrobés au soufre) ni les conséquences entraînées.
Cette méthode implique  la mis en ¿uvre d'un processus lent  qui peut ne pas être approprié à des essais au jour le jour. Des méthodes accélérées peuvent être utilisées, pourvu qu'elles soient corrélées avec la présente méthode. Un exemple d'une telle méthode accélérée est donné en annexe B. L'analyse de régression peut aussi être utilisée.

Počasi delujoča gnojila - Določevanje sproščanja hranil - Metoda za obložena gnojila

General Information

• Status: Published
• Publication Date: 23-Oct-2001
• Withdrawal Date: 29-Apr-2002
• ICS: 65.080 - Fertilizers
• Technical Committee: CEN/TC 260 - Fertilizers and liming materials
• Drafting Committee: CEN/TC 260/WG 4 - Non EEC fertilizers
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 08-Jul-2022
• Completion Date: 14-Apr-2025
• Ref Project: SIST EN 13266:2002 - Slow-release fertilizers - Determination of the release of the nutrients - Method for coated fertilizers

Overview

EN 13266:2001 (CEN) specifies a laboratory method for the determination of nutrient release from slow‑release, coated fertilizers. The standard applies only to nutrients released by non‑biological (physical) mechanisms - pH‑dependent hydrolysis and microbial degradation are excluded. The method is a direct elution test carried out at controlled temperature and is intended as a reference procedure; accelerated tests may be used if correlated to this standard (Annex B).

Key topics and technical requirements

• Test principle: periodic elution of a defined test portion in water and measurement of dissolved nutrient concentrations over time to quantify release profiles and calculate metrics such as initial release and longevity.
• Sample and medium:
  • Typical test portion: nominally 10.0 g (weighing to 0.01 g).
  • Elution volume: 500 ml of laboratory water (EN ISO 3696 grade 3).
  • Temperature control: maintain extractant at 25 ± 0.5 °C.
  • Stirring: magnetic stirrer (~300 min‑1) and covered beaker to avoid evaporation.
• Timing and sampling:
  • First determination after 24 ± 0.25 h; another mandatory check at day 28.
  • Recommendation: about ten time intervals up to the stated release time (example intervals given for multi‑month longevity).
  • Continue extraction until >75% of the nominal water‑soluble nutrient is leached.
• Performance criteria (Annex A):
  • Initial release ≤ 15% in 24 h.
  • ≤ 75% released in 28 days.
  • ≥ 75% released at the manufacturer’s stated release time (longevity).
• Accelerated methods (Annex B): elevated‑temperature procedures are described; accelerated tests must be correlated to the standard method (regression analysis recommended).
• Analytical and reporting:
  • Use standard analytical methods for nutrient determination; express initial release, released mass fraction, and longevity per formulas in the standard.
  • Inter‑laboratory precision established; reporting must include sampling method, sample ID, deviations, and any unusual observations.

Applications and who uses it

• Fertilizer manufacturers - product development, verification of coating performance and release claims (longevity, initial release).
• Independent testing laboratories - certification, quality control and compliance testing.
• Regulatory bodies and procurement - verifying product labels and performance specifications for slow‑release fertilizers.
• R&D organizations - correlating accelerated test methods to standardized reference behaviour.

Practical uses include validating slow‑release claims, comparing coating technologies, setting product specifications, and supporting marketing/label statements on nutrient release.

Related standards (references)

• EN 1482 - sampling of solid fertilizers and liming materials.
• EN ISO 3696 - water for analytical laboratory use.
• ISO 5725 - precision of measurement methods (inter‑laboratory testing referenced).

Keywords: EN 13266:2001, slow‑release fertilizers, coated fertilizers, nutrient release determination, CEN standard, accelerated test methods, initial release, longevity, water‑extractable nutrient.

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.JQRMLODLangsam freisetzende Düngemittel - Bestimmung der Freisetzungsrate von Nährstoffen - Verfahren für umhüllte DüngemittelEngrais a libération lente - Détermination du mode de libération des éléments nutritifs - Méthode applicable aux engrais enrobésSlow-release fertilizers - Determination of the release of the nutrients - Method for coated fertilizers65.080GnojilaFertilizersICS:Ta slovenski standard je istoveten z:EN 13266:2001SIST EN 13266:2002en01-november-2002SIST EN 13266:2002SLOVENSKI
STANDARD
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 13266October 2001ICS 65.080English versionSlow-release fertilizers - Determination of the release of thenutrients - Method for coated fertilizersEngrais à libération lente - Détermination du mode delibération des éléments nutritifs - Méthode applicable auxengrais enrobésLangsam freisetzende Düngemittel - Bestimmung derFreisetzungsrate von Nährstoffen - Verfahren für umhüllteDüngemittelThis European Standard was approved by CEN on 29 September 2001.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the 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 translationunder the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2001 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 13266:2001 ESIST EN 13266:2002

Criteria for release conditions.9Annex B (informative)
Accelerated test methods based on a elevated temperature.10Bibliography.12SIST EN 13266:2002

0,5)°C6 SamplingSampling and sample preparation shall be carried out in accordance with EN 1482.The method of sampling and of sample preparation shall be indicated in the test report. Take care to avoid damageto, or destruction of, the coating.Do not crush or grind the sample.7 Procedure7.1 Preparation of the test solutionTransfer 500 ml of water, conforming to grade 3 of EN ISO 3696, into a beaker (5.1). Weigh, to the nearest 0,01 g,(10
0,1) g of the fertilizer, add it to the water in the beaker and record the time. Weigh the beaker together with itscontents: the sample of fertilizer, water and stirring rod. Note the total mass to the nearest 1 g. Start the stirrer (5.3)at a rotational frequency of approximately 300 min-1. Cover the beaker with a lid to avoid evaporation of water andmaintain the temperature at (25
0,5)°C with the temperature-control equipment (5.4).Each time it is desired to make a nutrient determination (see 7.2), decant the solution into another beaker (5.1),taking care to avoid any of the undissolved fertilizer being carried over. Refill the beaker (5.1) with water(conforming to grade 3 of EN ISO 3696) at 25°C so as to achieve the previously recorded mass. Continueextraction immediately.Continue the extraction procedure until more than 75 % of the nominal quantity of water soluble nutrients has beenleached.NOTEThe mass ratio of fertilizer test portion to water is limited to a maximum of 2 % to avoid concentration effects7.2 Time intervals for periodic determinations of nutrient contentDetermine the nutrient content at about ten time intervals until the stated release time (for release condition 3). Thefirst determination shall be made after (24
0,25) h (for release condition 1), another one shall be made at day 28from the beginning of the elution (for release condition 2). Choose the intervals for taking the samples with respectto the amounts of leached nutrient concentration and their detection limits (for slow release criteria 1, 2, 3 seeannex A ).EXAMPLEDetermination intervals for a slow-release fertilizer intended to release nutrients over eight months:1) D1after 24 h (day 1);2) D7at day 7 after start, period from day 1 to day 7;3) D14at
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