Soil carbon saturation : implications for measurable carbon pool dynamics in long-term incubations
Stewart, Catherine E. , Paustian, Keith , Conant, Richard T., Plante, Alain F. , & Six, Johan (2009) Soil carbon saturation : implications for measurable carbon pool dynamics in long-term incubations. Soil Biology & Biochemistry, 41(2), pp. 357-366.
The efficiency of agricultural management practices to store SOC depends on C input level and how far a soil is from its saturation level (i.e. saturation deficit). The C Saturation hypothesis suggests an ultimate soil C stabilization capacity defined by four SOM pools capable of C saturation: (1) non-protected, (2) physically protected, (3) chemically protected and (4) biochemically protected. We tested if C saturation deficit and the amount of added C influenced SOC storage in measurable soil fractions corresponding to the conceptual chemical, physical, biochemical, and non-protected C pools. We added two levels of C-13- labeled residue to soil samples from seven agricultural sites that were either closer to (i.e., A-horizon) or further from (i.e., C-horizon) their C saturation level and incubated them for 2.5 years. Residue-derived C stabilization was, in most sites, directly related to C saturation deficit but mechanisms of C stabilization differed between the chemically and biochemically protected pools. The physically protected C pool showed a varied effect of C saturation deficit on C-13 stabilization, due to opposite behavior of the POM and mineral fractions. We found distinct behavior between unaggregated and aggregated mineral-associated fractions emphasizing the mechanistic difference between the chemically and physically protected C-pools. To accurately predict SOC dynamics and stabilization, C Saturation of soil C pools, particularly the chemically and biochemically protected pools, should be considered. (C) 2008 Elsevier Ltd. All rights reserved.
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|Item Type:||Journal Article|
|Keywords:||Agroecosystem; Carbon sequestration; 13C labeling; Particulate organic matter; Soil aggregation; Soil incubation; Soil carbon saturation; Soil organic matter stabilization|
|Subjects:||Australian and New Zealand Standard Research Classification > ENVIRONMENTAL SCIENCES (050000) > ECOLOGICAL APPLICATIONS (050100)|
Australian and New Zealand Standard Research Classification > ENVIRONMENTAL SCIENCES (050000) > SOIL SCIENCES (050300)
|Divisions:||Past > Institutes > Institute for Sustainable Resources|
|Copyright Owner:||Copyright 2009 Elsevier|
|Deposited On:||08 Oct 2010 08:46|
|Last Modified:||01 Mar 2012 00:19|
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