LeafAppearancePhase

The LeafAppearancePhase represents a developmental phase in a plant’s life cycle. The Final leaf number is fixed at the start of this phase. The remaining leaves continue to appear at a rate set by thermal time and phyllochron until flag leaf ligule appears and this phase is completed.

Overview

The LeafAppearancePhase is a phenological stage within the APSIM Next Generation framework that models the interval from a specified start stage to an end stage. The Final leaf number is fixed at the start of this phase (e.g. terminal spikelet). The remaining leaves continue to appear at a rate set by thermal time and phyllochron until flag leaf ligule appears and this phase is completed.

Inputs

The following input functions are required by LeafAppearancePhase:

FinalLeafNumber — Total number of leaves the plant will develop.
LeafNumber — The current number of leaves that have appeared on the plant.
FullyExpandedLeafNo — The number of leaves that have fully expanded.
InitialisedLeafNumber — The number of leaf primordia that have been initiated.

The following configuration parameters can be set:

Start — Name of the phenological stage at which this phase begins.
End — Name of the phenological stage at which this phase ends.
IsEmerged — Boolean flag indicating whether this phase begins post-emergence. Default is true.

Methodology

The LeafAppearancePhase calculates the fraction of the phase completed (\(F\)) using:

\[ F = \frac{LN_i - LN_0}{FLN - LN_0} \]

Where:

\(LN_i\) is the current leaf number at day \(i\),
\(LN_0\) is the leaf number at the start of the phase,
\(FLN\) is the final leaf number.

When all initialised leaf primordia have fully expanded, the phase is considered complete and moves to the next phase.

Events

Events Listened For

These are signals or notifications that the function listens for from other parts of the simulation:

Event	Purpose
Commencing	Resets the phase state variables at the start of the simulation

Events Raised to

No events are raised by this function.

Properties

Configurable and Reportable Properties

Property	Type	Description
Start	string	Phenological stage at which this phase begins
End	string	Phenological stage at which this phase ends
IsEmerged	bool	Indicates whether the phase occurs after emergence

Read-Only Reportable Properties

Property	Type	Description
FractionComplete	double	Fractional completion of the phase, ranging from 0 to 1

User Interface

LeafAppearancePhase can be added as a child of a Phenology node in the model tree. Right-click the Phenology node, select “Add Model…”, and search for LeafAppearancePhase in the Filter Box.

Practical Example

No practical example is available for this function.