Applications
Measurements
Plant fitting procedure
Parameter fitting process
-
The parameter identification process requires several steps possibly involving statistical analysis
on the structure, building a target file, and finally fitting the functional hidden parameters.
-
Step 1. Retrieving structural parameters.
This task can be simply deduced from plant architectural analysis when the structure is simple, especially when not branched, or when the structure is deterministic (palm trees, maize, beetroot, sunflower, etc.).
Otherwise structural parameters (more precisely rhythm ratio, pause, mortality and branching patterns) should be retrieved using the crown analysis approach, based on a statistical analysis.
Step 2. Simulating plant structure.
This step helps to validate structural parameter identification.
In these simulations, organ sizes can be adjusted by the user, like simple constant values.
Step 3. Building a target file.
This file retrieves output from simulations at different growth cycles, corresponding to different observation stages.
Hidden parameters are filled using default values.
However, at this stage, some measurable functional attributes can be set to their values, such as allometry parameters, expansion and function duration.
Step 4. Fitting the functional hidden parameters.
In the target file, outcomes such as leaf areas, fruit weights, internode lengths, etc. must be replaced with the measured values.
The parameters to be identified are then fitted, usually in several steps.
Sink and source functions on internodes, blades, petioles, flowers and fruits are classically evaluated first.
Secondary growth (rings) parameters are finally identified.
The overall fitting process may be reiterated, including on some structural aspects, especially when functional structural aspects are considered (fruit absorption for instance). Environmental condition changes can also be introduced in this loop.
Step 5. Applications
Once the parameters have been fitted, the calibrated model can be applied for various purposes, including for environmental pressure and density effect estimations.