- `LON` geographic longitude of site in degree.

- `LAT` geographic latitude of site in degree.

- `ELV` geographic elevation of site in m.a.s.l.

- `WHC` water-holding capacity of site in mm.

- `NI` site nutritional index (dimensionless).

- `RUEmax` maximum radiuation use efficiency in g DM per MJ.

- `w_FGA` relative weight of functional group A.

- `w_FGB` relative weight of functional group B.

- `w_FGC` relative weight of functional group C.

- `w_FGD` relative weight of functional group D.

- `sigmaGV` rate of GV respirative biomass loss (dimensionless).

- `sigmaGR` rate of GR respirative biomass loss (dimensionless).

- `T0` photosynthesis activation temperature (degree C).

- `T1` photosynthesis plateau temperature (degree C).

- `T2` photosynthesis max temperature (degree C).

- `KGV` basic senescence rate GV (dimensionless).

- `KGR` basic senescence rate GR (dimensionless).

- `KlGV` basic abscission rate GV (dimensionless).

- `KlGR` basic abscission rate GR (dimensionless).

- `maxOMDDV` organic matter digestibility in gram per gram DV.

- `minOMDDR` organic matter digestibility in gram per gram DR.

- `CO2_growth_factor` strength of effect of CO2 concentration on growth. See 
  parameter *b* in [fCO2_growth_mod()].

- `crop_coefficient` multiplicative factor K~c~ by which 
  reference evapotranspiration ET~0~ has to be multiplied to get the crop 
  evapotranspiration ET~c~: 
  ET~c~ = K~c~ ET~0~

- `senescence_cap` fraction c~s~ of *GRO* to which *SEN* is 
  limited: SEN~i~^max^ = c~s~ GRO~i~ 
  for *i* in *GV*, *GR*. Makes it less likely for grass population to die out.
  Can be set to large values in order to effectively disable senescence capping.
