BS ISO 21263:2017 INTERNATIONAL ISO STANDARD 21263 Firstedition 2017-12-15 Slow-release fertilizers Determination of the release of the nutrients Method for coated fertilizers Engrais a libération lente - Détermination du mode de libération des élements nutritifs - Méthode applicable aux engrais enrobés Reference number ISO 21263:2017(E) ISO @ IS0 2017 BS ISO 21263:2017 IS0 21263:2017(E) COPYRIGHTPROTECTEDDOCUMENT IS0 2017, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form written permission. Permission can be requested from either ISO at the address below or ISO's member body in the country of the requester. ISO copyrightoffice Ch. de Blandonnet 8 . CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 [email protected] www.iso.org ii @ IS0 2017 - All rights reserved BS ISO 21263:2017 IS0 21263:2017(E) Contents Page Foreword ..iv 1 Scope .1 2 Normative references ..1 3 Terms and definitions 4 Principle 5 Apparatus. ..2 6 Sampling. .2 7 Procedure .2 7.1 Preparation of the test solution .2 7.2 Time intervals for periodic determinations of nutrient content .3 7.3 Determination of the nutrient content. .3 7.4 Determination of the total water-extractable nutrient content ..3 8 Expression of results ..4 9 Precision ..4 9.1 General 4 9.2 Repeatability ..4 9.3 Reproducibility ..4 10 Test report ..5 Annex A (normative) Criteria for release conditions ..6 Annex B (informative) Accelerated test methods based on an elevated temperature .7 Bibliography 9 @ IS0 2017 - All rights reserved iii