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Modelling productivity of willow stands in Sweden

evaluation of concepts for radiation use efficiency and soil water and nitrogen availability

Noronha Sannervik, Angela (2003). Modelling productivity of willow stands in Sweden. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae. Silvestria, 1401-6230 ; 286
ISBN 91-576-6520-6
[Doctoral thesis]

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Abstract

The aim of this thesis was to answer the question: Which processes should be included in
a model to simulate willow production as a function of climate, soil and fertilisation
conditions?

Studies were carried out to determine: a) the radiation use efficiency of an unstressed
willow stand; b) to which degree willow growth can be described as a function of absorbed
radiation, shoot age and shoot mortality; c) to which extent model predictability is improved
by further including soil water availability and d) nitrogen availability. Model simulations
were tested against biomass production of 22 stands representing differences in location,
soil type and fertilisation level.

It was found that radiation use efficiency varies with shoot-age. This was attributed to
differences in canopy development, and to mortality caused by self-thinning. The absorbed
radiation, shoot age and shoot mortality could explain 70 to 85% of the observed variations
in stem biomass at harvest and 32 to 48% of the observed variations in annual production.
Incorporating simulations of soil water availability decreased model predictability except
for production of three-years-old shoots. Including simulations of soil water and nitrogen
availability improved the degree of explanation in some situations. For all stands, model
predictability of biomass at harvest was improved from r2 = 0.70 to r2 = 0.82 and of annual
biomass from r2 = 0.70 to r2 = 0.82. For low or not fertilised stands, only a slightly
improvement was obtained in explaining variations at harvest and none for variations of
annual biomass. For fertilised stands, model predictability was decreased except for
production of three-years-old shoots. Predictability of three-years old shoots production was
improved, for all situations, by including simulations of soil water and nitrogen availability.

For willow stands growing on former arable land in southern Sweden, variations on
biomass production at harvest, of stands with similar fertilisation level, can be simulated
from the absorbed radiation and shoot mortality caused by self-thinning. Simulations of soil
water and nitrogen availability are only worthy of including to explain yield variations of
stands with different fertilisation levels. Variations in biomass production between years
and sites are indicated to be poorly related to annual variations in solar radiation, shoot
mortality or soil water and nitrogen availability.

Authors/Creators:Noronha Sannervik, Angela
Title:Modelling productivity of willow stands in Sweden
Subtitle:evaluation of concepts for radiation use efficiency and soil water and nitrogen availability
Year of publishing :December 2003
Number:286
Number of Pages:31
Papers/manuscripts:
NumberReferences
ALLI II III IV
Place of Publication:Uppsala
Publisher:Department of Short Rotation Forestry, Swedish University of Agricultural Sciences
ISBN for printed version:91-576-6520-6
ISSN:1401-6230
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:F Plant production > F62 Plant physiology - Growth and development
Subjects:Not in use, please see Agris categories
Agrovoc terms:drought, growth, models, plant nutrition, salix viminalis, plant production, sweden
Keywords:droughts, growth, model complexity, nutrition, Salix viminalis, willow coppice systems
URN:NBN:urn:nbn:se:slu:epsilon-111
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-111
ID Code:421
Faculty:S - Faculty of Forest Sciences
Department:(S) > Institutionen för lövträdsodling (960101-050630)
Deposited By: Staff Epsilon
Deposited On:09 Dec 2003 00:00
Metadata Last Modified:22 Dec 2020 15:21

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