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United States Department of Agriculture

Agricultural Research Service

Title: Soil Structure and Community Function: the Distribution of Two C Cycle Enzymes in Soil Aggregates of a Prairie Chronosequence.

item Fansler, S - NORTHWEST NATL LAB
item Bolton, Harvey - NORTHWEST NATL LAB
item Bailey, Vanessa - NORTHWEST NATL LAB
item Smith, Jeffrey

Submitted to: Soil Ecology Society Conference
Publication Type: Abstract Only
Publication Acceptance Date: April 1, 2005
Publication Date: N/A

Technical Abstract: C sequestration is driven by the processes through which C is cycled into stable soil C pools. 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 in four soils of the tallgrass prairie restoration chronosequence at Fermi National Lab (Batavia, IL). The chronosequence soils were: native prairie (NP), agricultural (AG), and tallgrass prairie restored from agriculture in 1979 (RP-79) and 1993 (RP-93). Assays for '-glucosidase (E.C. and N-acetyl-'-glucosaminidase (NAGase, EC activities were conducted on four aggregate size fractions (>2 mm, 1-2 mm, 250µm-1 mm, and 2- 250 µm) 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 (µg PNP g-1 soil h-1) were greatest in the microaggregate (2 µm -250 µm) compared to the macroaggregate (>2 mm) fraction; however, microaggregates are a small proportion of each soil (<12%) compared to the macroaggregates (~75%). The RP soils have a hierarchal aggregate system with most of the enzyme activity in the largest aggregate fractions. The NP and AG soils show no hierarchal 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.

Last Modified: 3/30/2015
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