Preliminary Course.
Eco-Physiology
Photosynthesis.
A Light Use Efficiency Model
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Knowing the LUE and the irradiance intercepted, a simple crop growth model can be defined.
On a daily basis, dry biomass growth can be expressed as follows:
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dW = LUE . PAR . (1 - e-k LAI)
where:
dW is biomass growth rate ( in g.m-2.d-1)
LUE is Light Use Efficiency ( in g.MJ-1)
k is the extinction coefficient
LAI is Leaf Area Index
PAR is Photosynthetic Active Radiation incident on the crop (MJ.m-2.d-1)
Light use efficiency determined in winter for 3 plant densities with and without assimilation light for cut chrysanthemum.
(Graph: E. Heuvelink, WAGENINGEN UNIVERSITY)
Notes:
1. In some models, such as the GreenLab model, LUE is defined on a fresh biomass weight base with 80% water content.
2. Many applications assume constant LUE value as shown in the figure below, but LUE can be made dependent on CO2, temperature, light intensity, etc..
Light use efficiency determined for 3 light intensity experiments for cut chrysanthemum.
(Graph: E. Heuvelink, WAGENINGEN UNIVERSITY)