TY - JOUR

T1 - Do soil aggregates really protect encapsulated organic matter against microbial decomposition?

AU - Goebel, Marc O.

AU - Woche, Susanne K.

AU - Bachmann, Jörg

N1 - Funding Information: Financial support provided by the “Deutsche Forschungs-gemeinschaft DFG” (Priority program “Soils as source and sink for CO2 – mechanisms and regulation of organic matter stabilization in soils”, SPP1090, BA1359/5-1) for this study is greatly appreciated. Copyright: Copyright 2009 Elsevier B.V., All rights reserved.

PY - 2009/6

Y1 - 2009/6

N2 - Soil aggregates can provide an effective protection of organic matter against microbial decomposition as reported by several macroaggregate disruption studies. However, research on the role of aggregation for carbon mineralization was mainly focused on arable soils. In the present study we aim to clarify the impact of aggregation on organic matter protection by measuring carbon mineralization in terms of microbial respiration rates of intact macroaggregates (2-4 and 4-8 mm) and corresponding crushed aggregates from seven topsoil horizons from both arable and forest sites. For two arable and one forest soil we found a significantly (P < 0.001) lower carbon mineralization from intact aggregates as compared to the corresponding crushed material. The portion of aggregate protected carbon reached up to 30% for a grassland soil. For the other arable and forest soils no significant effect of aggregation was found. Similarly, no clear trend could be found for the protective capacity of different size fractions. We conclude that protection by aggregation is effective primarily for soils with a large pool of labile organic matter regardless of their usage as arable land or forest.

AB - Soil aggregates can provide an effective protection of organic matter against microbial decomposition as reported by several macroaggregate disruption studies. However, research on the role of aggregation for carbon mineralization was mainly focused on arable soils. In the present study we aim to clarify the impact of aggregation on organic matter protection by measuring carbon mineralization in terms of microbial respiration rates of intact macroaggregates (2-4 and 4-8 mm) and corresponding crushed aggregates from seven topsoil horizons from both arable and forest sites. For two arable and one forest soil we found a significantly (P < 0.001) lower carbon mineralization from intact aggregates as compared to the corresponding crushed material. The portion of aggregate protected carbon reached up to 30% for a grassland soil. For the other arable and forest soils no significant effect of aggregation was found. Similarly, no clear trend could be found for the protective capacity of different size fractions. We conclude that protection by aggregation is effective primarily for soils with a large pool of labile organic matter regardless of their usage as arable land or forest.

KW - Microbial respiration

KW - Organic matter stabilization

KW - Soil aggregates

UR - http://www.scopus.com/inward/record.url?scp=65549167268&partnerID=8YFLogxK

U2 - 10.2478/s11756-009-0065-z

DO - 10.2478/s11756-009-0065-z

M3 - Article

AN - SCOPUS:65549167268

VL - 64

SP - 443

EP - 448

JO - BIOLOGIA

JF - BIOLOGIA

SN - 0006-3088

IS - 3

ER -