TY - JOUR
T1 - Methodological uncertainty in estimating carbon turnover times of soil fractions
AU - Feng, Wenting
AU - Shi, Zheng
AU - Jiang, Jiang
AU - Xia, Jianyang
AU - Liang, Junyi
AU - Zhou, Jizhong
AU - Luo, Yiqi
N1 - Funding Information:
We would like to thank Dr. Kevin Wilcox and two anonymous reviewers for their insightful comments and suggestions on this article. This research is financially supported by the United States Department of Energy, Terrestrial Ecosystem Sciences grant DESC0008270 , and Biological Systems Research on the Role of Microbial Communities in Carbon Cycling Program grants DESC0004601 and DE-SC0010715 .
Publisher Copyright:
© 2016 Elsevier Ltd.
PY - 2016/9/1
Y1 - 2016/9/1
N2 - Improving predictions of soil organic carbon (SOC) dynamics by multi-compartment models requires validation of turnover times of different SOC pools. Techniques such as laboratory incubation and isotope analysis have been adopted to estimate C turnover times, yet no studies have systematically compared these techniques and assessed the uncertainties associated with them. Here, we tested whether C turnover times of soil fractions were biased by methodology, and how this changed across soil particle sizes and ecosystems. We identified 52 studies that quantified C turnover times in different soil particles fractionated either according to aggregate size (e.g., macro- versus micro-aggregates) or according to soil texture (e.g., sand versus silt versus clay). C turnover times of these soil fractions were estimated by one of three methods: laboratory incubation (16 studies), δ13C shift due to C3-C4 vegetation change (25 studies), and 14C dating (19 studies). All methods showed that C turnover times of soil fractions generally increase with decreasing soil particle size. However, estimates of C turnover times within soil fractions differed significantly among methods, with incubation estimating the shortest turnover times and 14C the longest. The short C turnover times estimated by incubation are likely due to optimal environmental conditions for microbial decomposition existing in these studies, which is often a poor representation of field conditions. The 13C method can only be used when documenting a successive C3 versus C4 vegetation shift. C turnover times estimated by 14C were systematically higher than those estimated by 13C, especially for fine soil fractions (i.e., silt and clay). Overall, our findings highlight methodological uncertainties in estimating C turnover times of soil fractions, and correction factors should be explored to account for methodological bias when C turnover times estimated from different methods are used to parameterize soil C models.
AB - Improving predictions of soil organic carbon (SOC) dynamics by multi-compartment models requires validation of turnover times of different SOC pools. Techniques such as laboratory incubation and isotope analysis have been adopted to estimate C turnover times, yet no studies have systematically compared these techniques and assessed the uncertainties associated with them. Here, we tested whether C turnover times of soil fractions were biased by methodology, and how this changed across soil particle sizes and ecosystems. We identified 52 studies that quantified C turnover times in different soil particles fractionated either according to aggregate size (e.g., macro- versus micro-aggregates) or according to soil texture (e.g., sand versus silt versus clay). C turnover times of these soil fractions were estimated by one of three methods: laboratory incubation (16 studies), δ13C shift due to C3-C4 vegetation change (25 studies), and 14C dating (19 studies). All methods showed that C turnover times of soil fractions generally increase with decreasing soil particle size. However, estimates of C turnover times within soil fractions differed significantly among methods, with incubation estimating the shortest turnover times and 14C the longest. The short C turnover times estimated by incubation are likely due to optimal environmental conditions for microbial decomposition existing in these studies, which is often a poor representation of field conditions. The 13C method can only be used when documenting a successive C3 versus C4 vegetation shift. C turnover times estimated by 14C were systematically higher than those estimated by 13C, especially for fine soil fractions (i.e., silt and clay). Overall, our findings highlight methodological uncertainties in estimating C turnover times of soil fractions, and correction factors should be explored to account for methodological bias when C turnover times estimated from different methods are used to parameterize soil C models.
KW - C
KW - C
KW - Fraction
KW - Incubation
KW - Soil organic carbon
KW - Turnover
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U2 - 10.1016/j.soilbio.2016.06.003
DO - 10.1016/j.soilbio.2016.06.003
M3 - Article
AN - SCOPUS:84975048485
SN - 0038-0717
VL - 100
SP - 118
EP - 124
JO - Soil Biology and Biochemistry
JF - Soil Biology and Biochemistry
ER -