Start | Index | Overview • PREV | UP | Calculates the effect of heat stress on leaf senescence .
When maximum temperature exceeds a threshold, leaf senescence increases. This module calculates the leaf senescence increase factor that can be used by biomass modules to adjust the leaf senescence rate.
\[ \begin{eqnarray} F_{heat}(T_{max},DVS) & = & \begin{cases} max(0,m\cdot (T_{max} - T_{C}) + F_{TC}) & \text{if} & T_{max} > T_C \quad \text{and} \quad DVS > DVS_C\\ 1 &\text{else} & \end{cases} \end{eqnarray} \] where \(F_{heat}\) is the calculated senescence factor dependend on the daily maximum temperature \(T_{max}\) and actual development stage \(DVS\), \(DVS_C\) is the critical dev stage, \(T_C\) is the critical temperature, \(F_{TC}\) the factor at the critical temperature and \(m\) the slope of the factor increment by temperature. With default values \(T_C = 34, m=0.5, F_{TC}=3\) the formula is equivalent to the formula in the referenced paper (A): \(F_{heat} = 4 - (1-(T_{max} -34°)/2)\)(A) Asseng, S.; Foster, I.; Turner N. C: The impact of temperature variability on wheat yields
| Content Type | Name | Description | Data Type | Unit | Min Value | Max Value | Default Value |
|---|---|---|---|---|---|---|---|
| constant | cDevStageCritical | development stage when heat stress on senescence starts | DOUBLE | 1 | - | - | 1.0 |
| constant | cFactorAtTempCritical | leaf senescence factor when maximum temperature equals critical temperature | DOUBLE | 1 | - | - | 3.0 |
| constant | cFactorSlope | increment of leaf senescence factor per degree Celsius | DOUBLE | °C-1 | - | - | 0.5 |
| constant | cTempCritical | temperature threshold when heat stress on leaf senescence begins | DOUBLE | °C | - | - | 34.0 |
| input | iDevStage | Development stage | DOUBLE | 1 | 0.0 | - | 0.0 |
| input | iTMax | Daily maximum temperature | DOUBLE | °C | - | - | 0.0 |
| out | LeafSenescenceFactor | leaf senescence factor due to heat stress | DOUBLE | 1 | - | - | 1.0 |