Parameter in the model

Parameter	Value	Description
ϕ_TRSA	0.0683575 m^2 g^-1	Reference root surface area per total biomass, used in nutrient stress function and maintenance costs for roots function, set to mean of community: $\varphi \mathrm{\_}TRSA=\text{mean}((1-\mathbf{abp})\cdot \mathbf{rsa})$
ϕ_TAMC	0.108293	Reference arbuscular mycorriza colonisation rate per total biomass, used in nutrient stress function and maintenance costs for mycorrhizae function, set to mean of community: $\varphi \mathrm{\_}TAMC=\text{mean}((1-\mathbf{abp})\cdot \mathbf{amc})$
ϕ_sla	0.008808 m^2 g^-1	Reference specific leaf area, used in senescence function, set to mean of community: $\varphi \mathrm{\_}sla=\text{mean}(\mathbf{sla})$
γ_RUEmax	0.003 kg MJ^-1	Maximum radiation use efficiency
γ_RUE_k	0.6	Light extinction coefficient
α_RUE_cwmH	0.998592	Reduction factor of radiation use efficiency at a height of 0.2 m ∈ [0, 1]
β_LIG_H	NaN	Exponent that coontrols how strongly taller plants intercept more light than smaller plants
α_WAT_rsa05	0.822698	Water stress growth reduction factor for species with mean trait: $TRSA=\varphi \mathrm{\_}TRSA$, when the plant available water equals: $W\mathrm{\_}p,txy=0.5$
β_WAT_rsa	8.12609	Slope of the logistic function that relates the plant available water to the water stress growth reduction factor
δ_WAT_rsa	1.60378 g m^-2	Controls how strongly species differ in their water stress growth reduction from the mean response
α_NUT_Nmax	35.0 g kg^-1	Maximum total soil nitrogen, on all the grassland sites of the Biodiversity Exploratories, the maximum total soil nitrogen is $30g\cdot k{g}^{-1}$
α_NUT_TSB	5001.26 kg ha^-1	Reference value, if the sum of the product of trait similarity and biomass of all species equals: $\sum TS\cdot B<1$, $\sum TS\cdot B=1$, $\sum TS\cdot B>1$ the nutrient adjustment factor $NUT\mathrm{\_}adj,txys$ is higher than one, one and lower than one, respectively
α_NUT_maxadj	10.0	Maximum of the nutrient adjustment factor, fixed for calibration
α_NUT_amc05	0.700429	Nutrient stress based on arbuscular mycorriza colonisation growth reduction factor for species with mean trait: $TAMC=\varphi \mathrm{\_}TAMC$, when the plant available nutrients equal: $N\mathrm{\_}p,txys=0.5$
α_NUT_rsa05	0.959764	Nutrient stress based on root surface area growth reduction factor for species with mean trait: $TRSA=\varphi \mathrm{\_}TRSA$, when the plant available nutrients equal: $N\mathrm{\_}p,txys=0.5$
β_NUT_rsa	8.13689	Slope of the logistic function that relates the plant available nutrients to the nutrient stress growth reduction factor based on root surface area & calibrated
β_NUT_amc	15.9892	Slope of the logistic function that relates the plant available nutrients to the nutrient stress growth reduction factor based on arbuscular mycorriza colonisation
δ_NUT_rsa	10.3304 g m^-2	Controls how strongly species differ in their nutrient stress growth reduction based on root surface area from the mean response
δ_NUT_amc	15.0	Controls how strongly species differ in their nutrients stress growth reduction based on arbuscular mycorriza colonisation from the mean response & calibrated
κ_ROOT_amc	0.0723991	Maximum growth reduction due to maintenance costs for mycorrhizae based on arbuscular mycorriza colonisation rate
κ_ROOT_rsa	0.00761945	Maximum growth reduction due to maintenance costs for fine roots based on root surface area
γ_RAD1	4.45e-6 ha MJ^-1	Controls the steepness of the linear decrease in radiation use efficiency for high $PAR\mathrm{\_}txy$ values
γ_RAD2	50000.0 MJ ha^-1	Threshold value of $PAR\mathrm{\_}txy$ from which starts a linear decrease in radiation use efficiency
ω_TEMP_T1	4.0 °C	Minimum temperature for growth
ω_TEMP_T2	10.0 °C	Lower limit of optimum temperature for growth
ω_TEMP_T3	20.0 °C	Upper limit of optimum temperature for growth
ω_TEMP_T4	35.0 °C	Maximum temperature for growth
ζ_SEA_ST1	787.414 °C	Threshold of the cumulative temperate since the beginning of the current year, the seasonality factor starts to decrease from $\zeta \mathrm{\_}SEAmax$ to $\zeta \mathrm{\_}SEAmin$ above $\zeta \mathrm{\_}SEA,ST\mathrm{\_}1-100°C$
ζ_SEA_ST2	1800.0 °C	Threshold of the cumulative temperate since the beginning of the current year, above which the seasonality factor is set to $\zeta \mathrm{\_}SEAmin$
ζ_SEAmin	0.987514	Minimum value of the seasonal growth effect
ζ_SEAmax	2.44419	Maximum value of the seasonal growth effect
α_SEN	0.0452193	Basic senescence rate
β_SEN_sla	1.41955	Controls the influence of the specific leaf area on the senescence rate
ψ_SEN_ST1	1765.52 °C	Threshold of the cumulative temperate since the beginning of the current year above which the senescence begins to increase
ψ_SEN_ST2	3000.0 °C	Threshold of the cumulative temperate since the beginning of the current year above which the senescence reaches the maximum senescence rate
ψ_SENmax	1.55784	Maximum senescence rate
β_GRZ_lnc	0.578292	Controls the influence of leaf nitrogen per leaf mass on grazer preference
β_GRZ_H	0.0563242	Controls the influence of height on grazer preference
η_GRZ	2.0	Scaling factor that controls at which biomass density additional feed is supplied by farmers, fixed for calibration
κ_GRZ	22.0 kg	Consumption of dry biomass per livestock and day
ϵ_GRZ_minH	0.05 m	Minimum height that is reachable by grazers
β_SND_WHC	0.5678	Slope parameter relating the sand content to the soil water content at the water holding capacity
β_SLT_WHC	0.9228	Slope parameter relating the silt content to the soil water content at the water holding capacity
β_CLY_WHC	0.9135	Slope parameter relating the clay content to the soil water content at the water holding capacity
β_OM_WHC	0.6103	Slope parameter relating the organic matter content to the soil water content at the water holding capacity
β_BLK_WHC	-0.2696 cm^3 g^-1	Slope parameter relating the bulk density to the soil water content at the water holding capacity
β_SND_PWP	-0.0059	Slope parameter relating the sand content to the soil water content at the permanent wilting point
β_SLT_PWP	0.1142	Slope parameter relating the silt content to the soil water content at the permanent wilting point
β_CLY_PWP	0.5766	Slope parameter relating the clay content to the soil water content at the permanent wilting point
β_OM_PWP	0.2228	Slope parameter relating the organic matter content to the soil water content at the permanent wilting point
β_BLK_PWP	0.02671 cm^3 g^-1	Slope parameter relating the bulk density to the soil water content at the permanent wilting point

Which method uses a parameter?

Parameter	Used in...
ϕ_TRSA	root_investment!; nutrient_reduction!; water_reduction!
ϕ_TAMC	root_investment!; nutrient_reduction!
ϕ_sla	initialize_senescence_rate!
γ_RUEmax	potential_growth!
γ_RUE_k	light_competition_height_layer!; potential_growth!
α_RUE_cwmH	potential_growth!
β_LIG_H	light_competition_simple!
α_WAT_rsa05	water_reduction!
β_WAT_rsa	water_reduction!
δ_WAT_rsa	water_reduction!
α_NUT_Nmax	input_nutrients!
α_NUT_TSB	nutrient_competition!
α_NUT_maxadj	nutrient_competition!
α_NUT_amc05	nutrient_reduction!
α_NUT_rsa05	nutrient_reduction!
β_NUT_rsa	nutrient_reduction!
β_NUT_amc	nutrient_reduction!
δ_NUT_rsa	nutrient_reduction!
δ_NUT_amc	nutrient_reduction!
κ_ROOT_amc	root_investment!
κ_ROOT_rsa	root_investment!
γ_RAD1	radiation_reduction!
γ_RAD2	radiation_reduction!
ω_TEMP_T1	temperature_reduction!
ω_TEMP_T2	temperature_reduction!
ω_TEMP_T3	temperature_reduction!
ω_TEMP_T4	temperature_reduction!
ζ_SEA_ST1	seasonal_reduction!
ζ_SEA_ST2	seasonal_reduction!
ζ_SEAmin	seasonal_reduction!
ζ_SEAmax	seasonal_reduction!
α_SEN	initialize_senescence_rate!
β_SEN_sla	initialize_senescence_rate!
ψ_SEN_ST1	seasonal_component_senescence
ψ_SEN_ST2	seasonal_component_senescence
ψ_SENmax	seasonal_component_senescence
β_GRZ_lnc	grazing!
β_GRZ_H	grazing!
η_GRZ	grazing!
κ_GRZ	grazing!
ϵ_GRZ_minH	grazing!
β_SND_WHC	input_WHC_PWP!
β_SLT_WHC	input_WHC_PWP!
β_CLY_WHC	input_WHC_PWP!
β_OM_WHC	input_WHC_PWP!
β_BLK_WHC	input_WHC_PWP!
β_SND_PWP	input_WHC_PWP!
β_SLT_PWP	input_WHC_PWP!
β_CLY_PWP	input_WHC_PWP!
β_OM_PWP	input_WHC_PWP!
β_BLK_PWP	input_WHC_PWP!

How to change a parameter value

import GrasslandTraitSim as sim
using Unitful

# default parameter values
sim.SimulationParameter()

# optimized/calibrated parameter values
sim.optim_parameter()

# you can change parameter values with keyword arguments, when you create the parameter object
p = sim.SimulationParameter(γ_RUE_k  = 0.65,  ϕ_TRSA = 0.05u"m^2 / g")

# or you can change the parameter values after the object is created
p.ϕ_TAMC = 0.1
p.ϕ_sla = 0.01u"m^2 / g"

p

┌──────────────┬───────────────────┐
│    Parameter │ Value             │
├──────────────┼───────────────────┤
│       ϕ_TRSA │ 0.05 m^2 g^-1     │
│       ϕ_TAMC │ 0.1               │
│        ϕ_sla │ 0.01 m^2 g^-1     │
│     γ_RUEmax │ 0.003 kg MJ^-1    │
│      γ_RUE_k │ 0.65              │
│   α_RUE_cwmH │ 0.95              │
│      β_LIG_H │ 1.0               │
│  α_WAT_rsa05 │ 0.9               │
│    β_WAT_rsa │ 7.0               │
│    δ_WAT_rsa │ 20.0 g m^-2       │
│   α_NUT_Nmax │ 35.0 g kg^-1      │
│    α_NUT_TSB │ 15000.0 kg ha^-1  │
│ α_NUT_maxadj │ 10.0              │
│  α_NUT_amc05 │ 0.95              │
│  α_NUT_rsa05 │ 0.95              │
│    β_NUT_rsa │ 15.0              │
│    β_NUT_amc │ 15.0              │
│    δ_NUT_rsa │ 20.0 g m^-2       │
│    δ_NUT_amc │ 10.0              │
│   κ_ROOT_amc │ 0.02              │
│   κ_ROOT_rsa │ 0.01              │
│       γ_RAD1 │ 4.45e-6 ha MJ^-1  │
│       γ_RAD2 │ 50000.0 MJ ha^-1  │
│    ω_TEMP_T1 │ 4.0 °C            │
│    ω_TEMP_T2 │ 10.0 °C           │
│    ω_TEMP_T3 │ 20.0 °C           │
│    ω_TEMP_T4 │ 35.0 °C           │
│    ζ_SEA_ST1 │ 775.0 °C          │
│    ζ_SEA_ST2 │ 1450.0 °C         │
│     ζ_SEAmin │ 0.9               │
│     ζ_SEAmax │ 1.5               │
│        α_SEN │ 0.05              │
│    β_SEN_sla │ 1.5               │
│    ψ_SEN_ST1 │ 775.0 °C          │
│    ψ_SEN_ST2 │ 3000.0 °C         │
│     ψ_SENmax │ 1.5               │
│    β_GRZ_lnc │ 1.2               │
│      β_GRZ_H │ 2.0               │
│        η_GRZ │ 2.0               │
│        κ_GRZ │ 22.0 kg           │
│   ϵ_GRZ_minH │ 0.05 m            │
│    β_SND_WHC │ 0.5678            │
│    β_SLT_WHC │ 0.9228            │
│    β_CLY_WHC │ 0.9135            │
│     β_OM_WHC │ 0.6103            │
│    β_BLK_WHC │ -0.2696 cm^3 g^-1 │
│    β_SND_PWP │ -0.0059           │
│    β_SLT_PWP │ 0.1142            │
│    β_CLY_PWP │ 0.5766            │
│     β_OM_PWP │ 0.2228            │
│    β_BLK_PWP │ 0.02671 cm^3 g^-1 │
└──────────────┴───────────────────┘

API

GrasslandTraitSim.SimulationParameter Type

Parameter of the GrasslandTraitSim.jl model

source