Description Usage Arguments Details Value See Also Examples

**Model description.** This model is a dynamic model
of crop growth for Maize cultivated in potential
conditions. The crop growth is represented by three state
variables, leaf area per unit ground area (leaf area
index, LAI), total biomass (B) and cumulative thermal
time since plant emergence (TT). It is based on key
concepts included in most crop models, at least for the
"potential production" part. In fact, this model does not
take into account any effects of soil water, nutrients,
pests, or diseases,...

1 2 | ```
maize.model(Tbase, RUE, K, alpha, LAImax, TTM, TTL,
weather, sdate, ldate)
``` |

`Tbase` |
: parameter the baseline temperature for growth (degreeCelsius) |

`TTM` |
: parameter temperature sum for crop maturity (degreeC.day) |

`TTL` |
: parameter temperature sum at the end of leaf area increase (degreeC.day) |

`K` |
: parameter extinction coefficient (relation between leaf area index and intercepted radiation) (-) |

`RUE` |
: parameter radiation use efficiency (?) |

`alpha` |
: parameter the relative rate of leaf area index increase for small values of leaf area index (?) |

`LAImax` |
: parameter maximum leaf area index (-) |

`weather` |
: weather data.frame for one single year |

`sdate` |
: sowing date |

`ldate` |
: last date |

The tree state variables are dynamic variables depending
on days after emergence: TT(day), B(day), and LAI(day).
The model has a time step dt of one day.

The model is
defined by a few equations, with a total of seven
parameters for the described process.

(1)
*TT(day+1) =
TT(day)+dTT(day)*

(2) *B(day+1) = B(day)+dB(day)*

(3)
*LAI(day+1) =
LAI(day)+dLAI(day)*

(4) *dTT(day) =
max((TMIN(day)+TMAX(day))/2-Tbase ; 0)*

(5)
*dB(day) = RUE*(1-e^{-K*LAI(day)*I(day)}),
if TT(day)<= TTM*

*dB(day) = 0, if TT(day)>TTM*

(6)
*alpha*dTT(day)*LAI(day)*max(LAImax-LAI(day);0), if
TT(day)<= TTL *

*dLAI(day) = 0 if TT(day)>TTL*

data.frame with daily TT, LAI,B

`maize.model2`

,
`maize.define.param`

,
`maize.simule`

, `maize.multisy`

,
`maize.simule240`

,`maize.simule_multisy240`

1 2 3 | ```
weather = maize.weather(working.year=2010, working.site=30,weather_all=weather_EuropeEU)
maize.model(Tbase=7, RUE=1.85, K=0.7, alpha=0.00243, LAImax=7, TTM=1200, TTL=700,
weather, sdate=100, ldate=250)
``` |

ZeBook documentation built on May 29, 2017, 5:14 p.m.

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