Carbon-13 Fractionation of Relic Soil Organic Carbon during Mineralization Effects Calculated Half-Lives

Soil Sci. Soc. Am. J. 71:1003–1009 doi:10.2136/sssaj2006.0193 Received 19 May 2006. *Corresponding author ([email protected]). © Soil Science Society of America 677 S. Segoe Rd. Madison WI 53711 USA All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permission for printing and for reprinting the material contained herein has been obtained by the publisher. To minimize erosion and improve long-term sustainability, SOC must be maintained. Soil organic C maintenance experiments typically rely on measuring nonisotopic changes in SOC with time and using differences in 13C isotopic discrimination in C3 and C4 plants to quantify C transfers across trophic levels. The nonisotopic approach to estimate SOC maintenance requirements is based on the equation ( ) NHC e a SOC