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Soil nitrogen fluxes and root uptake in the boreal forest

key processes to plant nitrogen nutrition

Oyewole, Olusegun Ayodeji (2015). Soil nitrogen fluxes and root uptake in the boreal forest. Diss. (sammanfattning/summary) Umeå : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2015:126
ISBN 978-91-576-8450-9
eISBN 978-91-576-8451-6
[Doctoral thesis]

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Abstract

Nitrogen (N) is essential for growth and net primary production of plants. However, N acquisition by plants is influenced by movement of soil N compounds from bulk soil to plant roots and uptake of N by roots. This thesis is aimed at deepening our knowledge on these key processes involved in plant N acquisition in the N-limited boreal forest. To address this aim, a novel, non-invasive microdialysis technique was employed. Amino acids dominated N fluxes in the boreal forest soils. Further, plant roots were shown to have the capacity to absorb organic and inorganic N present in the measured soil fluxes, but these soil fluxes, rather than root uptake, may limit plant N acquisition. The microdialysis technique was further developed to enable simultaneous estimation of diffusion and mass flow of N in soil. Applying this refinement of the technique in the field showed that mass flow significantly increased flux rates of soil N in the boreal forest ecosystem, and that it also altered the chemical composition of the N fluxes.

The results from the studies presented in this thesis highlight the potential of the microdialysis technique to improve our understanding of the intrinsic processes involved in N acquisition by plant roots. They also suggest that amino acids might comprise an important source of N for plants in the boreal forest ecosystem. The results suggest that mass flow plays an important role for plant N acquisition in the boreal forest, and mass flow might increase the share of nitrate, particularly in nutrient-rich ecosystems. This finding opens a discussion on the role of transpiration in plant N nutrition, with implications for our understanding of how plant N nutrition will be affected by, among other things, elevated CO2, increased temperatures, and N fertilization.

Authors/Creators:Oyewole, Olusegun Ayodeji
Title:Soil nitrogen fluxes and root uptake in the boreal forest
Subtitle:key processes to plant nitrogen nutrition
Series/Journal:Acta Universitatis agriculturae Sueciae (1652-6880)
Year of publishing :18 November 2015
Depositing date:27 November 2015
Volume:2015:126
Number of Pages:45
Papers/manuscripts:
NumberReferences
IInselsbacher, E., Oyewole, O.A., Näsholm, T. (2014). Early season dynamics of soil nitrogen fluxes in fertilized and unfertilized boreal forests. Soil Biology & Biochemistry 74, 167-176.
IIOyewole, O.A., Jämtgård, S., Gruffman, L., Inselsbacher, E., Näsholm, T. (2015). Soil diffusive fluxes constitute the bottleneck to tree nitrogen nutrition in a Scots pine forest. Plant and Soil. DOI: 10.1007/s11104-015-2680-5.
IIIOyewole, O.A., Inselsbacher, E., Näsholm, T. (2014). Direct estimation of mass flow and diffusion of nitrogen compounds in solution and soil. New Phytologist 201, 1056-1064.
IVOyewole, O.A., Inselsbacher, E., Näsholm, T., Jämtgård, S. Is plant nitrogen acquisition enhanced by transpiration? Estimating nitrogen diffusion and mass flow rates in boreal forest soils
Place of Publication:Umeå
Publisher:Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
Associated Programs and Other Stakeholders:SLU - Environmental assessment > Programme Acidification
SLU - Environmental assessment > Programme Climate
SLU - Environmental assessment > Programme Eutrophication
SLU - Environmental assessment > Programme Forest
SLU - Research Areas for the Future > Future Agriculture
SLU - Research Areas for the Future > Future Forests
SLU - Agricultural Sciences for Global Development > Efficiency in farming systems
ISBN for printed version:978-91-576-8450-9
ISBN for electronic version:978-91-576-8451-6
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:F Plant production > F61 Plant physiology - Nutrition
P Natural resources > P35 Soil fertility
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Agricultural Science
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Forest Science
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Soil Science
Agrovoc terms:boreal forests, forest soils, nitrogen cycle, nutrient availability, soil transport processes, roots, plant soil relations, nitrogen fertilizers
Keywords:amino acids, diffusion, mass flow, microdialysis, nitrogen availability, nitrogen uptake, plant nutrition, stable isotopes, transpiration
URN:NBN:urn:nbn:se:slu:epsilon-e-3101
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-3101
ID Code:12866
Faculty:S - Faculty of Forest Sciences
Department:(S) > Dept. of Forest Ecology and Management
Deposited By: Mr Olusegun Ayodeji Oyewole
Deposited On:30 Nov 2015 08:13
Metadata Last Modified:06 Feb 2016 05:28

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