QUT ePrints

Soil carbon saturation : evaluation and corroboration by long-term incubations

Stewart, Catherine E., Paustian, Keith, Conant, Richard T., Plante, Alain F., & Six, Johan (2008) Soil carbon saturation : evaluation and corroboration by long-term incubations. Soil Biology & Biochemistry, 40(7), pp. 1741-1750.

View at publisher

Abstract

Although current assessments of agricultural management practices on soil organic C (SOC) dynamics are usually conducted without any explicit consideration of limits to soil C storage, it has been hypothesized that the SOC pool has an upper, or saturation limit with respect to C input levels at steady state. Agricultural management practices that increase C input levels over time produce a new equilibrium soil C content. However, multiple C input level treatments that produce no increase in SOC stocks at equilibrium show that soils have become saturated with respect to C inputs. SOC storage of added C input is a function of how far a soil is from saturation level (saturation deficit) as well as C input level. We tested experimentally if C saturation deficit and varying C input levels influenced soil C stabilization of added C-13 in soils varying in SOC content and physiochemical characteristics. We incubated for 2.5 years soil samples from seven agricultural sites that were closer to (i.e., A-horizon) or further from (i.e., C-horizon) their C saturation limit. At the initiation of the incubations, samples received low or high C input levels of 13 C-labeled wheat straw. We also tested the effect of Ca addition and residue quality on a subset of these soils. We hypothesized that the proportion of C stabilized would be greater in samples with larger C Saturation deficits (i.e., the C- versus A-horizon samples) and that the relative stabilization efficiency (i.e., Delta SCC/Delta C input) would decrease as C input level increased. We found that C saturation deficit influenced the stabilization of added residue at six out of the seven sites and C addition level affected the stabilization of added residue in four sites, corroborating both hypotheses. Increasing Ca availability or decreasing residue quality had no effect on the stabilization of added residue. The amount of new C stabilized was significantly related to C saturation deficit, supporting the hypothesis that C saturation influenced C stabilization at all our sites. Our results suggest that soils with low C contents and degraded lands may have the greatest potential and efficiency to store added C because they are further from their saturation level. (c) 2008 Elsevier Ltd. All rights reserved.

Impact and interest:

34 citations in Scopus
Search Google Scholar™
29 citations in Web of Science®

Citation countsare sourced monthly from Scopus and Web of Science® citation databases.

These databases contain citations from different subsets of available publications and different time periods and thus the citation count from each is usually different. Some works are not in either database and no count is displayed. Scopus includes citations from articles published in 1996 onwards, and Web of Science® generally from 1980 onwards.

Citations counts from the Google Scholar™ indexing service can be viewed at the linked Google Scholar™ search.

ID Code: 37763
Item Type: Journal Article
Additional URLs:
Keywords: Agroecosystem; Soil incubation; 13C labeling; Soil carbon saturation; Soil carbon sequestration; Soil organic matter stabilization
DOI: 10.1016/j.soilbio.2008.02.014
ISSN: 0038-0717
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 2008 Elsevier
Deposited On: 08 Oct 2010 09:53
Last Modified: 01 Mar 2012 00:19

Export: EndNote | Dublin Core | BibTeX

Repository Staff Only: item control page