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Plant and forest dynamics in response to nitrogen availability

Franklin, Oskar (2003). Plant and forest dynamics in response to nitrogen availability. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae. Silvestria, 1401-6230 ; 285
ISBN 91-576-6519-2
[Doctoral thesis]

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Abstract

Theories and mathematical models were derived to analyse and predict plant and forest response to soil nitrogen (N) availability and atmospheric CO2 concentration. Soil carbon accumulation in response to long-term fertilisation was studied using measured soil C and 14C of the organic layer in a pine forest in Northern Sweden. Fertilisation increased forest growth and drastically reduced long-term litter decomposition through effects on the decomposers. In 100 years, twice as much carbon would be accumulated in the forest soil where N addition is high as where no N addition occurs. Root:shoot allocation of small plants was modelled using maximisation of relative growth rate, with and without explicit inclusion of N based maintenance respiration. The results agreed qualitatively with experimental data from birch and tomato plants and the agreement was considerably improved by the inclusion of maintenance respiration. Senescence and resorption as mechanisms of maximising photosynthetic production were used to predict LAI and resorption efficiency in relation to canopy N. This theory explained the observed LAI for four investigated plant species: red amaranth (Amaranthus cruentus), soybean (Glycine max), rice (Oryza sativa), and sorghum (Sorghum bicolor). Analytical expressions for forest photosynthesis, NPP, growth, LAI, root:leaf allocation and leaf N concentration were derived using a principle of maximal growth and optimisation of canopy N. Whole forest responses to N availability and atmospheric CO2 were predicted from basic physiological parameters. The results agreed well with results of elevated CO2 FACE experiments for sweetgum and loblolly pine trees. Finally, the findings of reduced decomposition and increased growth in response to fertilisation and elevated CO2 were evaluated in the context of the global carbon balance. A simple model of the responses of global carbon fluxes and pool turnover rates combined with a future scenario of CO2 emissions was subjected to a strong fertilisation effect on the boreal forest components. The results indicate that massive fertilisation could temporarily halt the rising of the atmospheric CO2.

Authors/Creators:Franklin, Oskar
Title:Plant and forest dynamics in response to nitrogen availability
Year of publishing :September 2003
Volume:285
Number of Pages:19
Papers/manuscripts:
NumberReferences
ALLI. Franklin O, Högberg P, Ekblad A, Ågren G I. Pine forest floor carbon accumulation in response to N and PK additions - bomb 14 C modelling and respiration studies (Ecosystems, in press). II. Ågren G I, Franklin O. Root:shoot ratios, optimisation and nitrogen productivity. (Accepted for publication in Annals of Botany) III. Franklin O & Ågren G I. 2002. Leaf senescence and resorption asmechanisms of maximising photosynthetic production during canopy development at N limitation. Functional Ecology 16, 727-733. IV. Franklin O. Optimal growth principle controls forest production,allocation and leaf properties in response to elevated CO2 and nitrogen (Manuscript).
Place of Publication:Uppsala
ISBN for printed version:91-576-6519-2
ISSN:1401-6230
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:P Natural resources > P34 Soil biology
Subjects:Not in use, please see Agris categories
Agrovoc terms:carbon, plant litter, growth, nitrogen cycle, nutrient availability, soil respiration, mathematical models
Keywords:carbon-14, decomposer efficiency, litter quality, mechanistic model, nitrogen deposition, NPP:GPP, optimality, plant theory, resorption effciency, soil respiration
URN:NBN:urn:nbn:se:slu:epsilon-73
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-73
ID Code:345
Department:(NL, NJ) > Institutionen för ekologi och miljövård
Deposited By: Oskar Franklin
Deposited On:16 Sep 2003 00:00
Metadata Last Modified:02 Dec 2014 10:04

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