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Sources of CO"2 efflux from soil and review of partitioning methods [An article from: Soil Biology and Biochemistry]
Book Details
Author(s)Y. Kuzyakov
PublisherElsevier
ISBN / ASINB000RR6UIM
ISBN-13978B000RR6UI4
AvailabilityAvailable for download now
Sales Rank99,999,999
MarketplaceUnited States 🇺🇸
Description
This digital document is a journal article from Soil Biology and Biochemistry, published by Elsevier in . The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.
Description:
Five main biogenic sources of CO"2 efflux from soils have been distinguished and described according to their turnover rates and the mean residence time of carbon. They are root respiration, rhizomicrobial respiration, decomposition of plant residues, the priming effect induced by root exudation or by addition of plant residues, and basal respiration by microbial decomposition of soil organic matter (SOM). These sources can be grouped in several combinations to summarize CO"2 efflux from the soil including: root-derived CO"2, plant-derived CO"2, SOM-derived CO"2, rhizosphere respiration, heterotrophic microbial respiration (respiration by heterotrophs), and respiration by autotrophs. These distinctions are important because without separation of SOM-derived CO"2 from plant-derived CO"2, measurements of total soil respiration have very limited value for evaluation of the soil as a source or sink of atmospheric CO"2 and for interpreting the sources of CO"2 and the fate of carbon within soils and ecosystems. Additionally, the processes linked to the five sources of CO"2 efflux from soil have various responses to environmental variables and consequently to global warming. This review describes the basic principles and assumptions of the following methods which allow SOM-derived and root-derived CO"2 efflux to be separated under laboratory and field conditions: root exclusion techniques, shading and clipping, tree girdling, regression, component integration, excised roots and insitu root respiration; continuous and pulse labeling, ^1^3C natural abundance and FACE, and radiocarbon dating and bomb-^1^4C. A short sections cover the separation of the respiration of autotrophs and that of heterotrophs, i.e. the separation of actual root respiration from microbial respiration, as well as methods allowing the amount of CO"2 evolved by decomposition of plant residues and by priming effects to be estimated. All these methods have been evaluated according to their inherent disturbance of the ecosystem and C fluxes, and their versatility under various conditions. The shortfalls of existing approaches and the need for further development and standardization of methods are highlighted.
Description:
Five main biogenic sources of CO"2 efflux from soils have been distinguished and described according to their turnover rates and the mean residence time of carbon. They are root respiration, rhizomicrobial respiration, decomposition of plant residues, the priming effect induced by root exudation or by addition of plant residues, and basal respiration by microbial decomposition of soil organic matter (SOM). These sources can be grouped in several combinations to summarize CO"2 efflux from the soil including: root-derived CO"2, plant-derived CO"2, SOM-derived CO"2, rhizosphere respiration, heterotrophic microbial respiration (respiration by heterotrophs), and respiration by autotrophs. These distinctions are important because without separation of SOM-derived CO"2 from plant-derived CO"2, measurements of total soil respiration have very limited value for evaluation of the soil as a source or sink of atmospheric CO"2 and for interpreting the sources of CO"2 and the fate of carbon within soils and ecosystems. Additionally, the processes linked to the five sources of CO"2 efflux from soil have various responses to environmental variables and consequently to global warming. This review describes the basic principles and assumptions of the following methods which allow SOM-derived and root-derived CO"2 efflux to be separated under laboratory and field conditions: root exclusion techniques, shading and clipping, tree girdling, regression, component integration, excised roots and insitu root respiration; continuous and pulse labeling, ^1^3C natural abundance and FACE, and radiocarbon dating and bomb-^1^4C. A short sections cover the separation of the respiration of autotrophs and that of heterotrophs, i.e. the separation of actual root respiration from microbial respiration, as well as methods allowing the amount of CO"2 evolved by decomposition of plant residues and by priming effects to be estimated. All these methods have been evaluated according to their inherent disturbance of the ecosystem and C fluxes, and their versatility under various conditions. The shortfalls of existing approaches and the need for further development and standardization of methods are highlighted.
