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Applied and Environmental Soil Science
Volume 2013 (2013), Article ID 968682, 5 pages
http://dx.doi.org/10.1155/2013/968682
Research Article

Biochar Alteration of the Sorption of Substrates and Products in Soil Enzyme Assays

1Soil Research Centre, Department of Geography and Environmental Science, University of Reading, Reading RG6 6DW, UK
2SRUC, Crop and Soil Systems Research Group, West Mains Road, Edinburgh EH9 3JG, UK
3Reading Scientific Services Ltd., Reading Science Centre, University of Reading, Reading RG6 6LA, UK

Received 3 July 2013; Accepted 14 August 2013

Academic Editor: Robert L. Bradley

Copyright © 2013 Mark Swaine 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.

Abstract

Pine wood and barley straw biochar amendments to Kettering and Cameroon sandy silt loam soils (15, 30, or 150 mg biochar g−1 soil) caused significant reductions (up to 80%, ) in concentrations of substrate and extractable product in soil dehydrogenase and phosphomonoesterase enzyme assays. Likely this was caused by increased solid-phase sorption of the chemicals in the presence of the biochars under assay conditions. The relationship between assay chemical sorption and biochar concentration depended on the chemical, soil type, biochar type, and their interactions; hence, no uniform correction factor could be derived. This biochar impact on assay constituents will limit the identification of genuine biochar effects on soil enzymes. It is recommended that the assumption of saturating substrate concentrations be checked and that product standards be matrix-matched when conducting enzyme assays with biochar-amended soil.