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Processes controlling production and transport of dissolved organic carbon in forest soils

Fröberg, Mats (2004). Processes controlling production and transport of dissolved organic carbon in forest soils. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae. Agraria, 1401-6249 ; 475
ISBN 91-576-6760-8
[Doctoral thesis]

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Abstract

Dissolved organic carbon (DOC) leached from the O horizon of forest soils is a major source of soil organic carbon in the mineral soil, where a major proportion of the organic carbon in forest ecosystems is located. The relative contribution of recent litter and humified organic matter to the leaching of DOC from the O horizon is still being debated. In the present work, I studied the sources of DOC leached from the O horizon by manipulating the amounts of litter and humus and measuring DOC concentrations and fluxes, isotopic composition (13C and 14C) and chemical characteristics (measured by NMR, UV absorbance and fractionation into hydrophilic and hydrophobic compounds). A computer model (DyDOC) was used to simulate the DOC leaching processes. Furthermore, DOC was measured at different soil moisture conditions at three sites along a climate gradient in Sweden. In addition, 14C measurements of DOC were made at two of these sites to reveal the fate of the DOC leached from the O horizon. I concluded that about half or more of the DOC leached from recent litter is lost during passage through the O horizon. Despite this, both recent litter in the Oi horizon and more humified organic matter in the Oe and Oa horizons contribute significantly to the DOC leaving the O horizon, but with the major proportion coming from the Oe and Oa horizons. To successfully model DOC leaching, the DyDOC model had to be modified to allow DOC to also be leached from recent litter. Measurements along the climatic gradient showed that the concentration and fluxes were highest in the south and lowest in the north. I suggest that these differences can be related to differences in net primary production. Both differences in mean annual temperature and the gradient in nitrogen status from south to north contribute to this effect of net primary production. Soil moisture had no effect on DOC leaching out of the O horizon. The DOC concentration in the B horizon, which is a sink for DOC, is largely governed by the physical and chemical properties of the mineral soil. The 14C measurements showed that the major proportion of the DOC in the B horizon is derived from the carbon stored in the mineral soil itself, rather than in the O horizon, suggesting extensive exchange of DOC by sorption/desorption processes in the mineral soil.

Authors/Creators:Fröberg, Mats
Title:Processes controlling production and transport of dissolved organic carbon in forest soils
Year of publishing :August 2004
Volume:475
Number of Pages:39
Papers/manuscripts:
NumberReferences
ALLI. Fröberg, M., Berggren, D., Bergkvist, B., Bryant C. & Knicker, H. Contributions of Oi, Oe and Oa horizons to dissolved organic matter in forest floor leachates. Geoderma 113: 311-322. II. Fröberg, M., Berggren Kleja, D., Bergkvist, B., Tipping, E. & Mulder, J. Dissolved organic carbon leaching from a coniferous forest floor – a field manipulation experiment. (Submitted) III. Tipping, E. Fröberg, M., Berggren Kleja, D., Mulder, J. & Bergkvist, B. DOC leaching from a coniferous forest floor – modelling a manipulation experiment. (Manuscript) IV. Fröberg, M., Berggren Kleja, D. & Hagedorn F. The contribution of fresh litter to dissolved organic carbon leached from a coniferous forest floor. (Submitted) V. Fröberg, M., Berggren, D., Bergkvist, B., Bryant C. & Mulder, J. Concentration and fluxes of dissolved organic carbon (DOC) in three Norway spruce stands along a climatic gradient in Sweden. Biogeochemistry (In press)
Place of Publication:Uppsala
ISBN for printed version:91-576-6760-8
ISSN:1401-6249
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:P Natural resources > P33 Soil chemistry and physics
P Natural resources > P34 Soil biology
Subjects:Not in use, please see Agris categories
Agrovoc terms:organic matter, carbon, dissolving, picea abies, radiocarbon dating, forest soils, sweden
Keywords:dissolved organic matter, water-extractable organic carbon, Norway spruce, radiocarbon, forest floor, biogeochemistry
URN:NBN:urn:nbn:se:slu:epsilon-292
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-292
ID Code:603
Department:(NL, NJ) > Dept. of Soil Sciences
Deposited By: Mats Fröberg
Deposited On:23 Aug 2004 00:00
Metadata Last Modified:02 Dec 2014 10:05

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