Start | Index | Overview • PREV | UP | The daily increment of vernalisation days is determined by daily average temperature iDAVTEMP
\[ \begin{eqnarray} VDI(iDAVTEMP) & = & \left\{ \begin{array}{l} 0 & \text{if} \quad iDAVTEMP \lt cTlowCritical\\ \frac{iDAVTEMP - cTlowCritical}{cTlow - cTlowCritical} & \text{if} \quad cTlowCritical \le iDAVTEMP \lt cTlow \\ 1 & \text{if} \quad cTlow \le iDAVTEMP \lt cThigh \\ \frac{cThighCritical - iDAVTEMP}{cThighCritical - cThigh} & \text{if} \quad cThigh \le iDAVTEMP \lt cThighCritical \\ 0 & \text{if} \quad cThighCritical \le iDAVTEMP\\ \end{array} \right. \end{eqnarray} \]And sVernalDays is incremented by VDI(iDAVTEMP).
VernalisationFactor (VF) is determined by the sVernalDays (VD)
\[ \begin{eqnarray} VF(VD) & = & \left\{ \begin{array}{l} 0 & \text{if} \quad VD \lt cVernalDaysMin\\ \frac{VD - cVernalDaysMin}{cVernalDaysMax - cVernalDaysMin} & \text{if} \quad cVernalDaysMin \le VD \lt cVernalDaysMax \\ 1 & \text{if} \quad cVernalDaysMax \le VD \\ \end{array} \right. \end{eqnarray} \]DayLength is calculated from current DOY and cLatitude
Photoresponse curve is interpolated from cPhotoresponseTable, which is a double array, holding the duration (in hours) in the even entries and the coresponding factors in the odd entries.
The PhotoresponseFactor is then chosen from the interpolated curve according to the Daylength.
After anthesis, no daylength effects are taken into account (PhotoresponseFactor = 1).
Before anthesis:
\[ \begin{eqnarray} RTSUM & = & iTSumBaseAnt \cdot Min(PhotoresponseFactor, VernalisationFactor) \end{eqnarray} \]After anthesis:
\[ \begin{eqnarray} RTSUM & = & iTSumBaseMat \cdot Min(PhotoresponseFactor, VernalisationFactor) \end{eqnarray} \]cApplyPhotoresponse and cApplyVernalisation control whether photoresponse, vernalisation or both are applied. If the control variables are false, the coresponding factor is always 1, meaning that the effect is not applied.
The state sVernalDays has to be reset on each sowing. Therefore the input iDoSow has to be provided.
Goudriaan, H.H. Van Laar, 1994. Modelling Potential Crop Growth Processes, Kluwer Academic Publishers, Dordrecht (1994) 238 pp
| Content Type | Name | Description | Data Type | Unit | Min Value | Max Value | Default Value |
|---|---|---|---|---|---|---|---|
| constant | cApplyPhotoresponse | Flag to activate photo response (True: daylength sensitive crops) | BOOLEAN | 1 | - | - | true |
| constant | cApplyVernalisation | Flag to activate vernalisation (True: crops requiring vernalisation for flower initialisation | BOOLEAN | 1 | - | - | true |
| constant | cLatitude | Latitude of the simulated location | DOUBLE | ° | 0.0 | 90.0 | 60.0 |
| constant | cPhotoperiodTableFactor | Correction factor of development rate in dependence of day length (c.f. PHOTTB) | DOUBLEARRAY | 1 | - | - | 0.0 0.0 1.0 1.0 |
| constant | cPhotoperiodTableHour | Day length for correction factor of development (c.f. PHOTTB) | DOUBLEARRAY | h | - | - | 0.0 8.0 20.0 24.0 |
| constant | cPhotoresponseTable | Crop specific photo response table as function of daylength in hours | DOUBLEARRAY | 1 | - | - | - |
| constant | cThigh | Upper temperature threshold for vernalisation; days with higher mean air temperature are not fully considered as a vernalisation day | DOUBLE | °C | -40.0 | 50.0 | 10.0 |
| constant | cThighCritical | Upper temperature threshold for vernalisation; days with higher mean air temperature don't contribute at all for vernalisation day | DOUBLE | °C | -40.0 | 50.0 | 17.0 |
| constant | cTlow | Lower temperature threshold for vernalisation, days with lower mean air temperature are not fully considered as a vernalisation day | DOUBLE | °C | -40.0 | 50.0 | 3.0 |
| constant | cTlowCritical | Lower critical temperature threshold for vernalisation, days with lower mean air temperature don't contribute at all for vernalisation day | DOUBLE | °C | -40.0 | 50.0 | -4.0 |
| constant | cVernalDaysMax | Crop specific maximum number of days required for vernalisation | INT | 1 | 0 | 400 | 70 |
| constant | cVernalDaysMin | Crop specific minimum number of days required for vernalisation | INT | 1 | 0 | 100 | 10 |
| input | iDAVTMP | Daily mean air temperature | DOUBLE | °C | 0.0 | 50.0 | - |
| input | iDevStage | Development stage of the crop (1.0=anthesis, 2.0=physiological maturity) | DOUBLE | 1 | 0.0 | 3.0 | - |
| input | iDevStageBaseShoot | Development stage for base shoot | DOUBLE | 1 | 0.0 | 10000.0 | 0.5 |
| input | iDoSow | true if sowing day | BOOLEAN | 1 | - | - | false |
| input | iTSumBaseAnt | Daily effective temperature before anthesis | DOUBLE | °C | 0.0 | 10000.0 | - |
| input | iTSumBaseMat | Daily effective temperature after anthesis | DOUBLE | °C | 0.0 | 10000.0 | - |
| input | iTSumBaseShoot | Daily effective temperature after shooting - if given | DOUBLE | °C | 0.0 | 10000.0 | - |
| state | sPhotoresponseArray | Photo response array as function of daylength in minutes | DOUBLEARRAY | 1 | 0.0 | 20.0 | - |
| state | sVernalDays | actual Vernal Days | DOUBLE | 1 | 0.0 | 400.0 | 0.0 |
| out | DayLength | Day Length in minutes | INT | min | 0 | 1441 | 0 |
| out | PhotoresponseFactor | daily photoresponse factor | DOUBLE | 1 | 0.0 | 1.0 | 0.0 |
| out | RTSUM | Daily effective temperature used to calculate the temperature sum and development stage at a given day | DOUBLE | °C | 0.0 | 50.0 | - |
| out | VernalisationFactor | daily vernalisation factor | DOUBLE | 1 | 0.0 | 1.0 | 0.0 |