Murdoch University Research Repository

Welcome to the Murdoch University Research Repository

The Murdoch University Research Repository is an open access digital collection of research
created by Murdoch University staff, researchers and postgraduate students.

Learn more

Quantification of deep soil carbon by a wet digestion technique

Sangmanee, P., Dell, B., Harper, R.J.ORCID: 0000-0003-0268-2917 and Henry, D.J.ORCID: 0000-0002-9629-4423 (2017) Quantification of deep soil carbon by a wet digestion technique. Soil Research, 55 (1). pp. 78-85.

Link to Published Version: http://dx.doi.org/10.1071/SR15297
*Subscription may be required

Abstract

Two wet digestion methods were evaluated using pure kaolinite as background for quantifying small concentrations of carbon (<0.05% total organic carbon (TOC)) in deep kaolinitic regolith in south-Western Australia. The limit of detection and limit of quantification of the Walkley-Black method (0.015 and 0.050% TOC respectively) were approximately five times lower than those of the Heanes method (0.085 and 0.281% TOC respectively). Both methods showed excellent linearity (R2>0.99) using prepared standards (lignin, humic acid, cellulose and chitin mixed with kaolinite and their combinations), in the concentration range 0.008-1.000% TOC. However, the percentage carbon recovery values were underestimated for chitin. The Walkley-Black method (TOCWB, %) was evaluated with 94 calibration and 27 validation deep soil samples (1-35m soil depth) and compared with a dry combustion (Elementar) technique (TOCactual, %). The predictive equation (TOCactual≤1.66TOCWB+0.018) (R2≤0.91) obtained from the calibration set agreed well with the benchmark dry combustion values (root mean square error≤0.017) and is recommended for quantification of deep soil carbon in other kaolinitic regoliths.

Item Type: Journal Article
Murdoch Affiliation: School of Veterinary and Life Sciences
Publisher: CSIRO
URI: http://researchrepository.murdoch.edu.au/id/eprint/35277
Item Control Page Item Control Page