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Title: Can intra-aggregate pore structures affect the aggregate's effectiveness in protecting carbon?

Abstract

Aggregates are known to provide physical protection to soil organic matter shielding it from rapid decomposition. Spatial arrangement and size distribution of intra-aggregate pores play an important role in this process. This study examined relationships between intra-aggregate pores measured using X-ray computed micro-tomography images and concentrations of total C in 4–6 mm macro-aggregates from two contrasting land use and management practices, namely, conventionally tilled and managed row crop agricultural system (CT) and native succession vegetation converted from tilled agricultural land in 1989 (NS). Previous analyses of these aggregates indicated that small (<15 μm) and large (>100 μm) pores prevail in NS aggregates while medium (30–90 μm) pores are more abundant in CT aggregates (Kravchenko et al., 2011; Wang et al., 2012). We hypothesized that these differences in pore size distributions affect the ability of macro-aggregates to protect C. The results of this study supported this hypothesis. Consistent with greater heterogeneity of pore distributions within NS aggregates we observed higher total C and greater intra-aggregate C variability in NS as compared with CT aggregates. Total C concentrations and intra-aggregate C standard deviations were negatively correlated with fractions of medium sized pores, indicating that presence of such pores was associated with lowermore » but more homogeneously distributed total C. While total C was positively correlated with presence of small and large pores. The results suggest that because of their pore structure NS macro-aggregates provide more effective physical protection to C than CT aggregates.« less

Authors:
; ; ; ;  [1]
  1. MSU
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
NSFOTHERDOE - BASIC ENERGY SCIENCES
OSTI Identifier:
1063006
Resource Type:
Journal Article
Journal Name:
Soil Biology and Biochemistry
Additional Journal Information:
Journal Volume: 57; Journal ID: ISSN 0038-0717
Publisher:
Elsevier
Country of Publication:
United States
Language:
ENGLISH

Citation Formats

Ananyeva, K, Wang, W, Smucker, A J.M., Rivers, M L, and Kravchenko, A N. Can intra-aggregate pore structures affect the aggregate's effectiveness in protecting carbon?. United States: N. p., 2012. Web. doi:10.1016/j.soilbio.2012.10.019.
Ananyeva, K, Wang, W, Smucker, A J.M., Rivers, M L, & Kravchenko, A N. Can intra-aggregate pore structures affect the aggregate's effectiveness in protecting carbon?. United States. doi:10.1016/j.soilbio.2012.10.019.
Ananyeva, K, Wang, W, Smucker, A J.M., Rivers, M L, and Kravchenko, A N. Thu . "Can intra-aggregate pore structures affect the aggregate's effectiveness in protecting carbon?". United States. doi:10.1016/j.soilbio.2012.10.019.
@article{osti_1063006,
title = {Can intra-aggregate pore structures affect the aggregate's effectiveness in protecting carbon?},
author = {Ananyeva, K and Wang, W and Smucker, A J.M. and Rivers, M L and Kravchenko, A N},
abstractNote = {Aggregates are known to provide physical protection to soil organic matter shielding it from rapid decomposition. Spatial arrangement and size distribution of intra-aggregate pores play an important role in this process. This study examined relationships between intra-aggregate pores measured using X-ray computed micro-tomography images and concentrations of total C in 4–6 mm macro-aggregates from two contrasting land use and management practices, namely, conventionally tilled and managed row crop agricultural system (CT) and native succession vegetation converted from tilled agricultural land in 1989 (NS). Previous analyses of these aggregates indicated that small (<15 μm) and large (>100 μm) pores prevail in NS aggregates while medium (30–90 μm) pores are more abundant in CT aggregates (Kravchenko et al., 2011; Wang et al., 2012). We hypothesized that these differences in pore size distributions affect the ability of macro-aggregates to protect C. The results of this study supported this hypothesis. Consistent with greater heterogeneity of pore distributions within NS aggregates we observed higher total C and greater intra-aggregate C variability in NS as compared with CT aggregates. Total C concentrations and intra-aggregate C standard deviations were negatively correlated with fractions of medium sized pores, indicating that presence of such pores was associated with lower but more homogeneously distributed total C. While total C was positively correlated with presence of small and large pores. The results suggest that because of their pore structure NS macro-aggregates provide more effective physical protection to C than CT aggregates.},
doi = {10.1016/j.soilbio.2012.10.019},
journal = {Soil Biology and Biochemistry},
issn = {0038-0717},
number = ,
volume = 57,
place = {United States},
year = {2012},
month = {11}
}