Mineralization of low molecular weight carbon substrates in soil solution under laboratory and field conditions
- 作者：H. Glanvillea ; afp857@bangor.ac.uk ; J. Rouska ; b ; P. Golyshinc ; D.L. Jonesa
- 关键词：Decomposition ; Dissolved organic carbon ; DOC ; SOM ; Turnover rates
- 刊名：Soil Biology & Biochemistry
- 出版年：2012
- 期刊代码：96_00380717
- 类别：abs
- 出版时间：May, 2012
- 卷：48
- 期：Complete
- 页码：88-95
- 文件大小：406 K
摘要
A more detailed mechanistic understanding of how low molecular weight (MW) carbon (C) substrates are mineralized within the rhizosphere by soil microbial communities is crucial to accurately model terrestrial C fluxes. Currently, most experiments regarding soil C dynamics are conducted ex-situ (laboratory) and can fail to account for key variables (e.g. temperature and soil water content) which vary in-situ. In addition, ex-situ experiments are often highly invasive, e.g. severing root and mycorrhizal networks, changing the input and concentrations of low MW exudates within soil. The aim of this study was to directly compare the mineralization rates of 31 common low MW聽C substrates under ex-聽and in-situ conditions. In addition, we also assessed the inter-annual field variability of substrate mineralization rates. We added trace concentrations of 31 individual 14C-labelled common low MW聽C substrates into the top soil of an agricultural grassland and monitored the mineralization rates by capturing 14CO2 evolved from the soil over 7聽d. Our results showed that the contribution of low MW聽C components to soil respiration was highly reproducible between parallel studies performed either in-situ or ex-situ. We also found that differences in the mineralization of individual compounds were more variable inter-annually in the field than between the laboratory and the field. Our results suggest that laboratory-based C聽mineralization data can be used to reliably parameterize C models but that multiple experimental measurements should be made over time to reduce uncertainty in model parameter estimation.