Comparisons of Three Methods for Organic and Inorganic Carbon in Calcareous Soils of Northwestern China

With increasing interest in the carbon cycle on arid land, there is an urgent need to quantify both soil organic carbon (SOC) and inorganic carbon (SIC) thus to assess various methods. Here, we present a study employing three methods for determinations of SOC and SIC in the Yanqi Basin of northwest...

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Main Authors:	Wang, Xiujun, Wang, Jiaping, Zhang, Juan
Format:	Online
Language:	English
Published:	Public Library of Science 2012
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3432125/

id	pubmed-3432125
recordtype	oai_dc
spelling	pubmed-34321252012-09-05 Comparisons of Three Methods for Organic and Inorganic Carbon in Calcareous Soils of Northwestern China Wang, Xiujun Wang, Jiaping Zhang, Juan Research Article With increasing interest in the carbon cycle on arid land, there is an urgent need to quantify both soil organic carbon (SOC) and inorganic carbon (SIC) thus to assess various methods. Here, we present a study employing three methods for determinations of SOC and SIC in the Yanqi Basin of northwest China. We use an elemental analyzer for both SOC and SIC, the Walkley-Black method for SOC, a modified pressure calcimeter method for SIC, and a simple loss-on-ignition (LOI) procedure for determinations of SOC and SIC. Our analyses show that all three approaches produce consistently low values for SOC (1–14 g kg−1) and high values for SIC (8–53 g kg−1). The Walkley-Black method provides an accurate estimate of SOC with 100% recovery for most soil samples. The pressure calcimeter method is as accurate as the elemental analysis for measuring SIC. In addition, SOC and SIC can be accurately estimated using a two-step LOI approach, i.e., (1) combustion at 375°C for 17 hours to estimate SOC, and (2) subsequent combustion at 800°C for 12 hours to estimate SIC. There are strong linear relationships for both SOC and SIC between the elemental analysis and LOI method, which demonstrates the capability of the two-step LOI technique for estimating SOC and SIC in this arid region. Public Library of Science 2012-08-31 /pmc/articles/PMC3432125/ /pubmed/22952957 http://dx.doi.org/10.1371/journal.pone.0044334 Text en © 2012 Wang et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Wang, Xiujun Wang, Jiaping Zhang, Juan
spellingShingle	Wang, Xiujun Wang, Jiaping Zhang, Juan Comparisons of Three Methods for Organic and Inorganic Carbon in Calcareous Soils of Northwestern China
author_facet	Wang, Xiujun Wang, Jiaping Zhang, Juan
author_sort	Wang, Xiujun
title	Comparisons of Three Methods for Organic and Inorganic Carbon in Calcareous Soils of Northwestern China
title_short	Comparisons of Three Methods for Organic and Inorganic Carbon in Calcareous Soils of Northwestern China
title_full	Comparisons of Three Methods for Organic and Inorganic Carbon in Calcareous Soils of Northwestern China
title_fullStr	Comparisons of Three Methods for Organic and Inorganic Carbon in Calcareous Soils of Northwestern China
title_full_unstemmed	Comparisons of Three Methods for Organic and Inorganic Carbon in Calcareous Soils of Northwestern China
title_sort	comparisons of three methods for organic and inorganic carbon in calcareous soils of northwestern china
description	With increasing interest in the carbon cycle on arid land, there is an urgent need to quantify both soil organic carbon (SOC) and inorganic carbon (SIC) thus to assess various methods. Here, we present a study employing three methods for determinations of SOC and SIC in the Yanqi Basin of northwest China. We use an elemental analyzer for both SOC and SIC, the Walkley-Black method for SOC, a modified pressure calcimeter method for SIC, and a simple loss-on-ignition (LOI) procedure for determinations of SOC and SIC. Our analyses show that all three approaches produce consistently low values for SOC (1–14 g kg−1) and high values for SIC (8–53 g kg−1). The Walkley-Black method provides an accurate estimate of SOC with 100% recovery for most soil samples. The pressure calcimeter method is as accurate as the elemental analysis for measuring SIC. In addition, SOC and SIC can be accurately estimated using a two-step LOI approach, i.e., (1) combustion at 375°C for 17 hours to estimate SOC, and (2) subsequent combustion at 800°C for 12 hours to estimate SIC. There are strong linear relationships for both SOC and SIC between the elemental analysis and LOI method, which demonstrates the capability of the two-step LOI technique for estimating SOC and SIC in this arid region.
publisher	Public Library of Science
publishDate	2012
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3432125/
_version_	1611553678159773696

Comparisons of Three Methods for Organic and Inorganic Carbon in Calcareous Soils of Northwestern China

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