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Applied and Environmental Soil Science
Volume 2009, Article ID 219379, 14 pages
Research Article

Tillage Effects on Spatiotemporal Variability of Particulate Organic Matter

1Department of Plant Sciences, University of California, Davis, CA 95616, USA
2Department of Land, Air and Water Resources, University of California, Davis, CA 95616, USA

Received 19 December 2008; Revised 29 April 2009; Accepted 20 August 2009

Academic Editor: Oliver Dilly

Copyright © 2009 Juhwan Lee et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This study was performed to evaluate effects of no-till (NT) and standard tillage (ST) on POM in two 15-ha neighboring fields from 2003 to 2004. We also evaluated the effects of minimum tillage (MT) on POM after both NT and ST fields were converted to MT in the summer of 2005. We quantified C and N stocks of three size fractions (53–250, 250–1000, and 1000–2000 ) of POM (0–0.15 m depth). The POM-C 53–250  and 250–1000  fractions decreased by 25% and 36% after six months under ST, whereas relatively little change occurred under NT, suggesting significant tillage effects over the period 2003-2004. Only small changes in POM content then occurred under MT on both fields. Changes in POM-N were similar to POM-C changes upon tillage conversions. This suggests that reduced tillage did not lead to soil C increase compared to ST but may help maintain the level of soil C for a typical California farming system. Short-term, field level variability of POM was primarily affected by tillage and was further influenced by clay content, bulk density, and scale of observation.