BS-EN-13266-2001.pdf

BRITISH STANDARD BS EN 13266:2001 Slow-release fertilizers Determination of the release of the nutrients Method for coated fertilizers The European Standard EN 13266:2001 has the status of a British Standard ICS 65.080 ? BS EN 13266:2001 This British Standard, having been prepared under the direction of the Materials and Chemicals Sector Policy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 15 August 2002 © BSI 15 August 2002 ISBN 0 580 40277 0 National foreword This British Standard is the official English language version of EN 13266:2001. The UK participation in its preparation was entrusted to Technical Committee CII/37, Fertilizers and related chemicals, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Additional information The United kingdom voted against the acceptance of this standard at the Formal Vote stage. The principle UK objections were as follows: a) Criteria for the release conditions of slow release fertilizers are specified in the normative Annex A. This is outside of the scope of this test method. b) The “stated release time” is defined, in 3.4, as a property determined by the test method, when it should be the time stated by the manufacturer. c) Clause 9 gives requirements for the precision of the test method described in the standard. The UK deemed the precision of the main method in 9 to be poor and that an “accelerated test” would be even less reliable. d) There are no details or references to the standard analytical methods for the determination of nutrient concentration as required in 7.3, 7.4 and B.3.3. e) Clause 7 describes the procedure for the determination of the release of the nutrients. 7.2 describes the time intervals at which to determine the nutrient content of the fertilizer. The example of the time intervals is given in 7.2 for a slow release fertilizer intended to release nutrients over eight months. It is deemed that the time intervals need to be spread beyond the expected “longevity” in order that a more accurate value of nutrient content can be determined. f) The apparatus for controlling the temperature of the water, described in 5.4, could be further defined. g) A description of the “sensor system”, referred to in B.2.1.7 for use in the accelerated test of Annex B, is not provided. h) B.3.3 refers to the measurement of electrical conductivity, however no method is provided Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standard Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 12, an inside back cover and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. DateComments EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM EN 13266 October 2001 ICS 65.080 English version Slow-release fertilizers - Determination of the release of the nutrients - Method for coated fertilizers Engrais à libération lente - Détermination du mode de libération des éléments nutritifs - Méthode applicable aux engrais enrobés Langsam freisetzende Düngemittel - Bestimmung der Freisetzungsrate von Nährstoffen - Verfahren für umhüllte Düngemittel This 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 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 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 Management Centre has the same status as the official versions. 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 STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels © 2001 CENAll rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 13266:2001 E EN 13266:2001 (E) 2 Contents page Foreword3 1Scope 4 2Normative references 4 3Terms and definitions4 4Principle4 5Apparatus .5 6Sampling.5 7Procedure .5 8Expression of results 6 9Precision.7 10Test report 8 Annex A (normative) Criteria for release conditions.9 Annex B (informative) Accelerated test methods based on a elevated temperature.10 Bibliography12 EN 13266:2001 (E) 3 Foreword This European Standard has been prepared by Technical Committee CEN /TC 260, “Fertilizers and liming materials“, the secretariat of which is held by DIN. 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 April 2002, and conflicting national standards shall be withdrawn at the latest by April 2002. Annex A is normative and annex B is informative. This standard includes a Bibliography. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. EN 13266:2001 (E) 4 1 Scope 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. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text, and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies (including amendments). EN 1482, Sampling of solid fertilizers and liming materials. EN ISO 3696, Water for analytical laboratory use Specification and test methods (ISO 3696:1987). 3 Terms and definitions For the purposes of this European Standard, the following terms and definitions apply. 3.1 release transfer of a nutrient from the fertilizer to the receiving medium (water) 3.2 slow release release under the defined conditions meeting each of the criteria set out in annex A 3.3 initial release of a nutrient the mass fraction in percent of a nutrient released during the first 24 h after the start of the test 3.4 stated release time time period between the start of the test and the release of a given minimum percentage of the specified nutrient NOTEThis may also be referred to as longevity. See annex A. 3.5 coated fertilizer fertilizer that is encapsulated, by covering it with a water-insoluble material, in order to reduce its release rate in water 4 Principle Elution of a test portion of a fertilizer with a specified volume of water. Determination of the concentration of the nutrient(s), that have been dissolved in defined time intervals. EN 13266:2001 (E) 5 5 Apparatus Ordinary laboratory apparatus and, in particular, the following: 5.1 Glass beakers, of capacity 800 ml, with a lid 5.2 One mark volumetric flask, 500 ml capacity 5.3 Magnetic stirrer, with a magnetic rod with a size of 25 mm, or any other suitable stirrer 5.4 Temperature-control equipment, capable of maintaining the medium at the temperature of (25 ? 0,5)°C 6 Sampling Sampling 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 damage to, or destruction of, the coating. Do not crush or grind the sample. 7 Procedure 7.1 Preparation of the test solution Transfer 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 its contents: 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 and maintain 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. Continue extraction immediately. Continue the extraction procedure until more than 75 % of the nominal quantity of water soluble nutrients has been leached. NOTEThe mass ratio of fertilizer test portion to water is limited to a maximum of 2 % to avoid concentration effects 7.2 Time intervals for periodic determinations of nutrient content Determine the nutrient content at about ten time intervals until the stated release time (for release condition 3). The first determination shall be made after (24 ? 0,25) h (for release condition 1), another one shall be made at day 28 from the beginning of the elution (for release condition 2). Choose the intervals for taking the samples with respect to the amounts of leached nutrient concentration and their detection limits (for slow release criteria 1, 2, 3 see annex 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 day 14, period from day 7 to day 14; 4) D21at day 21, period from day 14 to day 21; EN 13266:2001 (E) 6 5) D28at day 28 (week 4, 1 month), period from day 21 to day 28; 6) D56at day 56 (week 8, 2 months), period from day 28 to day 56; 7) D84at day 84 (week 12, 3 months), period from day 56 to day 84; 8) D112at day 112 (week 16, 4 months), period from day 84 to day 112; 9) D168at day 168 (week 24, 6 months), period from day 112 to day 168; 10) D224at day 224 (week 32, 8 months), period from day 168 to day 224. 7.3 Determination of the nutrient content Take aliquots as appropriate to determine the concentrations of the nutrients, using standard analytical methods, and calculate the total extracted amount of nutrients. Note the result as “Dn + nutrient symbol“ for each nutrient under examination. 7.4 Determination of the total water-extractable nutrient content Transfer 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, ground or treated in some other appropriate manner to destroy any coating and add it to the water in the beaker. 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 and maintain the temperature at (25 ? 0,5)°C with the temperature- control equipment (5.4) for about 24 h. Take aliquots as appropriate without any undissolved part to determine the concentrations of the nutrients extracted as desired, using standard analytical methods. Note the result as “C? + nutrient symbol“ for each nutrient under examination. 8 Expression of results The initial release, m1, expressed as mass fraction in percent of total water extractable nutrient(s) is given by equation (1). ? ? ? C D m 1 1 100 (1) The longevity d75%, expressed in days, is given by the interpolation equation (2): ? ? ? lh llh l75% 75 mm mdd dd ? ? ?(2) The released mass fraction within n days, mn, expressed as a percentage, is given by equation (3). ? ? ? ? )n1i ( i 100 n to C D m(3) where mnis the released mass fraction within n days; C?is the total water extractable nutrient content (7.4), given as mass fraction in percent; Dnis the nutrient content of the sample at day n (released between day n-1 and day n); nis the number of days; EN 13266:2001 (E) 7 dlis the day until less than 75 % of nutrient(s) are released; dhis the day until more than 75 % of nutrient(s) are released; mlis the released mass fraction until dl; mhis the released mass fraction until dh. 9 Precision 9.1 General The precision data of this method has been established by an international inter-laboratory test (see ISO 5725:19861). In this test, eight samples of different origin, nutrient compositions, coating and longevity were investigated and slow release properties were determined by measurement of the electrical conductivity and determination of the nitrogen content by 11 laboratories in six countries. For the values obtained for repeatability limit and reproducibility limit, a probability level of 95 % holds. 9.2 Repeatability The absolute difference between two single test results, obtained under repeatabili