ISO INTERNATIONAL STANDARD 14240-1 First edition 1997-01-15 Soil quality--Determination of soil microbial biomass - Part 1: Substrate-induced respiration method Qualite du sol-Détermination de la biomasse microbienne du sol - Partie1:Méthodeparrespiration induiteparsubstrat ISO Reference number ISO 14240-1:1997(E) ISO14240-1:1997(E) Foreword Iso (the International Organization for Standardization) is a worldwide federation of national standards bodies (IsO member bodies). The work of preparing International Standards is normally carried out through IsO technical liaison with isO, also take part in the work. isO collaborates closely with the International Electrotechnical Commission(lEC)onallmattersofelectrotechnicalstandardization. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO14240-1 was prepared by Technical Committee ISO/TC 190,Soil quality, Subcommittee SC 4, Biological methods. ISO 14240 consists of the following parts, under the general title Soil quality - Determination of soil microbial biomass: Part1:Substrate-induced respirationmethod Part 2: Fumigation-extraction method @ISO1997 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from thepublisher. International Organization for Standardization Case postale 56 . CH-1211 Geneve 20 . Switzerland Internet [email protected] X.400 C=ch; a=400net; p=iso; O=isocs; S=central Printed in Switzerland ii @ISO ISO 14240-1:1997(E) Introduction which occurs in soils. The purpose of determining the microbial biomass of soils is to allow assessment of the materials on the natural microbial population. ii