HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Franzluebbers, A. J. Articles by Arshad, M. A. Search for Related Content PubMed Articles by Franzluebbers, A. J. Articles by Arshad, M. A. Agricola Articles by Franzluebbers, A. J. Articles by Arshad, M. A.

Soil Microbial Biomass and Mineralizable Carbon of Water-Stable Aggregates

USDA-ARS, Southern Piedmont Conservation Research Center, 1420 Experiment Station Road, Watkinsville, GA 30677

M. A. Arshad^*

Agriculture and Agri-Food Canada, Northern Agriculture Research Centre, Box 29, Beaverlodge, Alberta, T0H 0C0, Canada

*Corresponding author (arshadc{at}em.agr.ca).

ABSTRACT

Biophysical alterations of agricultural soils following adoption of zero tillage (ZT) deserve investigation in order to better understand the processes of soil organic C (SOC) sequestration and turnover. We determined the vertical distribution of soil microbial biomass C (SMBC), C mineralized in 24 d under standard conditions, and basal soil respiration (BSR) in five water-stable aggregate classes. Four soils (loam, silt loam, clay loam, and clay) from the Peace River region of northern Alberta and British Columbia were sampled following 4 to 16 yr under comparison of conventional shallow tillage (CT) and ZT. Macroaggregates (>0.25 mm) had greater SMBC, more C mineralized in 24 d, and higher BSR than microaggregates at a depth of 0 to 50 mm. Differences between macro- and microaggregates in these properties decreased with soil depth. Carbon mineralized in 24 d and SMBC were 9 ± 9% greater (mean of four soils ± standard deviation among soils) under ZT than under CT in macroaggregates, but were 6 ± 11% lower in whole soil due to lower amounts in microaggregates under ZT than under CT. Macroaggregate-protected SOC to a depth of 200 mm was 6.7 ± 1.9 g m^–2 under CT and 9.8 ± 2.6 g m^–2 under ZT. Soil organic C in macroaggregates, which had high concentrations of active pools of SOC, appeared to have been shunted into the more stable microaggregate fraction after disturbance with CT. Unlike in temperate, humid climates, decomposition of SOC during the passage from macro- to microaggregates may have been limited by the frigid, semiarid climate.

Contribution from the Northern Agriculture Research Centre.

Received for publication February 19, 1996.

This article has been cited by other articles:

				A. J. Franzluebbers and J. A. Stuedemann Soil Carbon and Nitrogen Pools in Response to Tall Fescue Endophyte Infection, Fertilization, and Cultivar Soil Sci. Soc. Am. J., March 1, 2005; 69(2): 396 - 403. [Abstract] [Full Text] [PDF]

				U. M. Sainju, T. H. Terrill, S. Gelaye, and B. P. Singh Soil Aggregation and Carbon and Nitrogen Pools under Rhizoma Peanut and Perennial Weeds Soil Sci. Soc. Am. J., January 1, 2003; 67(1): 146 - 155. [Abstract] [Full Text] [PDF]

				M. E. Schutter and R. P. Dick Microbial Community Profiles and Activities among Aggregates of Winter Fallow and Cover-Cropped Soil Soil Sci. Soc. Am. J., January 1, 2002; 66(1): 142 - 153. [Abstract] [Full Text] [PDF]

				A.J. Franzluebbers, R.L. Haney, C.W. Honeycutt, H.H. Schomberg, and F.M. Hons Flush of Carbon Dioxide Following Rewetting of Dried Soil Relates to Active Organic Pools Soil Sci. Soc. Am. J., March 1, 2000; 64(2): 613 - 623. [Abstract] [Full Text]

				I.C. Mendes, A.K. Bandick, R.P. Dick, and P.J. Bottomley Microbial Biomass and Activities in Soil Aggregates Affected by Winter Cover Crops Soil Sci. Soc. Am. J., July 1, 1999; 63(4): 873 - 881. [Abstract] [Full Text]