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Distribution of two C cycle enzymes in soil aggregates of a prairie chronosequence

Permanent URL:
http://handle.nal.usda.gov/10113/14898
Abstract:
Knowledge of the cycling and compartmentalization of soil C that influence C storage may lead to the development of strategies to increase soil C storage potentials. The objective of this study was to use soil hydrolases and soil aggregate fractionation to explore the relationship between C cycling activity and soil aggregate structure. The prairie chronosequence soils were native prairie (NP) and agricultural (AG) and tallgrass prairies restored from agriculture in 1979 (RP-79) and 1993 (RP-93). Assays for β-glucosidase (E.C. 3.2.1.21) and N-acetyl-β-glucosaminidase (NAGase, EC 3.2.1.30) activities were conducted on four aggregate size fractions (>2 mm, 1-2 mm, 250 micrometer-1 mm, and 2-250 micrometer) from each soil. There were significantly greater amounts of >2-mm aggregates in the RP-79 and RP-93 soils compared to the NP and AG soils due to rapid C accumulation from native plant establishment. Activities for both enzymes (micrograms PNP g-1 soil h-1) were greatest in the microaggregate (2-250 micrometers) compared to the macroaggregate (>2 mm) fraction; however, microaggregates are a small proportion of each soil (<12%) compared to the macroaggregates (approximately75%). The RP soils have a hierarchical aggregate system with most of the enzyme activity in the largest aggregate fractions. The NP and AG soils show no hierarchical structure based on aggregate C accretion and significant C enzyme activity in smaller aggregates. The distribution of enzyme activity may play a role in the storage of C whereby the aggrading restored soils may be more susceptible to C loss during turnover of macroaggregates compared to the AG and NP soils with less macroaggregates.
Author(s):
Fansler, S.J. , Smith, J.L. , Bolton, H. Jr. , Bailey, V.L.
Subject(s):
prairie soils , agricultural soils , carbon sequestration , soil enzymes , soil aggregates , soil structure , chronosequences , fractionation , enzyme activity
Format:
p. 17-23.
Note:
Includes references
Source:
Biology and fertility of soils 2005 Nov., v. 42, no. 1
Language:
English
Year:
2005
Collection:
Journal Articles, USDA Authors, Peer-Reviewed
File:
Download [PDF File]
Rights:
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.