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]
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: $W\mathrm{\_}p,t=0.5$
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
ω_NUT_totalN	0.1 kg g^-1	Controls the influence of the total soil nitrogen on the nutrient index
ω_NUT_fertilization	0.001 ha kg^-1	Controls the influence of the fertilization rate on the nutrient index
β_TS	1.0	Scales the similarity for nutrient uptake traits (root surface area and arbuscular and mycorriza colonisation rate), which is used for competition for nutrients (very dissimilar species compete less strongly for nutrients). If $\beta \mathrm{\_}TS=0$, all trait similiarities are set to 1 and the trait similarity has no effect on the competition for nutrients, with increasing $\beta \mathrm{\_}TS$ the effect of the trait similarity on the nutrient competition becomes stronger.
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 $NUT\mathrm{\_}adj,ts$ 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: $N\mathrm{\_}p,ts=0.5$
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: $N\mathrm{\_}p,ts=0.5$
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 $PAR\mathrm{\_}t$ values
γ_RAD2	50000.0 MJ ha^-1	Threshold value of $PAR\mathrm{\_}t$ 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!
α_WAT_rsa05	water_reduction!
β_WAT_rsa	water_reduction!
δ_WAT_rsa	water_reduction!
ω_NUT_totalN	input_nutrients!
ω_NUT_fertilization	input_nutrients!
β_TS	similarity_matrix!
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              │
│         α_WAT_rsa05 │ 0.9               │
│           β_WAT_rsa │ 7.0               │
│           δ_WAT_rsa │ 20.0 g m^-2       │
│        ω_NUT_totalN │ 0.1 kg g^-1       │
│ ω_NUT_fertilization │ 0.001 ha kg^-1    │
│                β_TS │ 1.0               │
│           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