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| Van der Heijden, G.W.A.M.; De Visser, P.H.B.; Heuvelink, E.. |
| The aim of this chapter is to give an overview of the measurements needed for development and parameterization of a functional-structural crop model. Special emphasis will be given to measurements for structural/architectural processes. Size (area, length, width, thickness, volume) of the various organs (e.g., leaves, internodes, flowers, fruits and roots), as well as number of organs, 3D position and time of measurement need to be recorded. Existing methods for full 3D data capture and automatic feature extraction still present many problems. Therefore, human-operated sonic or magnetic trackers are at the moment more suitable to extract and store relevant information. Physiological processes like photosynthesis, transpiration and carbon allocation require... |
| Tipo: Conference proceedings |
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| Ano: 2007 |
URL: http://library.wur.nl/ojs/index.php/frontis/article/view/1368 |
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| De Visser, P.H.B.; Van der Heijden, G.W.A.M.; Heuvelink, E.; Carvalho, S.M.P.. |
| An integration of structural and physiological models is used to simulate 3D plant growth and visual appearance of cut chrysanthemum, reacting to environmental factors. Measurements to calibrate the model include 3D data of digitized plants as well as a number of measurements and observations on harvested plants, including biomass per organ. The structural module is based on the L-systems algorithm. This L-system calculates temperature- and light-driven development, branching pattern and flower formation. In this 3D-structural model existing rules for physiological processes are incorporated, enabling calculation of carbon dynamics. A 3D radiosity method is used to calculate light absorption of every organ (leaf) at an hourly basis. Hourly photosynthesis... |
| Tipo: Conference proceedings |
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| Ano: 2007 |
URL: http://library.wur.nl/ojs/index.php/frontis/article/view/1383 |
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| Heuvelink, E.; Marcelis, L.F.M.; Bakker, M.J.; Van der Ploeg, A.. |
| Quantifying the relevance of different plant traits for yield and quality under different growth conditions can improve the efficiency of a breeding programme. Crop models are powerful tools to give guidance to breeding, because model calculations enable the analysis of many different situations (sensitivity analysis and scenario studies). Three case studies of using crop growth models to evaluate physiological traits potentially used in breeding programmes are presented. The models used are explanatory models, with several submodels; e.g., for light interception, leaf photosynthesis, organ formation and biomass partitioning. Case study 1: It is hypothesized that yield improvement of cut chrysanthemum can be obtained by a higher specific leaf area (SLA) or... |
| Tipo: Conference proceedings |
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| Ano: 2007 |
URL: http://library.wur.nl/ojs/index.php/frontis/article/view/1308 |
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| Marcelis, L.F.M.; Heuvelink, E.. |
| The simulation of carbon allocation among plant organs is one of the weakest features of crop growth models. This paper briefly discusses five concepts of modelling carbon partitioning: 1. Descriptive allometry, proposing a predetermined ratio between the (relative) growth rates of plant organs; 2. Functional equilibrium, proposing an equilibrium between root and shoot activity; 3. Canonical modelling, a mathematical approach based on only a qualitative understanding of the allocation process; 4. Sink regulation, proposing allocation to be determined by sink strengths of the different organs; and 5. Transport resistance, calculating carbon transport from source to sink through a resistance and its utilization in the sink organs. These five concepts are... |
| Tipo: Conference proceedings |
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| Ano: 2007 |
URL: http://library.wur.nl/ojs/index.php/frontis/article/view/1375 |
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