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Microbial response to the addition of soluble organic substrates

Hoyle, F.C.ORCID: 0000-0001-6946-918X and Murphy, D.V. (2007) Microbial response to the addition of soluble organic substrates. Soil Research, 45 (7). p. 559.

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Soil microbial activity is often limited by the absence of readily available carbon (C) based substrates. Addition of a range of soluble organic substrates to soil has been shown to either accelerate or constrain the rate of CO2-C evolution. The aim of this study was to investigate the capacity of the microbial population to become activated in response to small additions of glucose-C (10–50 µg C/g soil) and 19 other soluble organic substrates (30 µg C/g soil) in soil either amended or not with cellulose. Rapid utilisation (equivalent to 25–35%) of added glucose was demonstrated in an initial flush of respiratory activity measured as CO2-C. However, the cumulative amount of respired C in 23 days indicated no additional release of CO2-C from the native soil organic matter (SOM) following application of glucose to soils, and a highly variable secondary phase of C mineralisation distinct from the initial glucose mineralisation phase. Although several C substrates resulted in the evolution of ‘extra’ CO2-C, no obvious association was observed between the response and the chemical structure of each substrate.

Item Type: Journal Article
Publisher: CSIRO Publishing
Copyright: © CSIRO 2007
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