loadTreatment: Load treatment parameters

In landsepi: Landscape Epidemiology and Evolution

Load treatment parameters

Description

Loads the list of treatment parameters required by the model (initialised at 0 , i.e. absence of treatments)

Usage

loadTreatment()

Details

Chemical treatment is applied in a polygon only if disease severity (i.e. I/N) in this polygon exceeds the threshold given by treatment_application_threshold. Treatment efficiency is maximum (i.e. equal to the parameter treatment_efficiency) at the time of treatment application (noted t*); then it decreases with time (i.e. natural pesticide degradation) and host growth (i.e. new biomass is not protected by treatments): protected by treatments):Efficiency of the treatment at time t after the application date is given by: efficiency(t) = treatment\_efficiency / (1 + exp(a-b*C(t))) with C(t)= C_1 * C_2:

• C_1 = exp(- treatment\_degradation\_rate * \Delta t) is the reduction of fungicide concentration due to time (e.g. natural degradation, volatilization, weathering), with \Delta t = t - t* the timelag passed since the time of treatment application.

• C_2 = min(1, N(t*) / N(t)) is the reduction of fungicide concentration due to plant growth, since new plant tissue is not covered by fungicide. N(t*) and N(t) being the number of host individuals a the time of treatment t* and at time t, respectively.

• a \in [3.5 ; 4.5] and b \in [8 ; 9] are shape parameters.

Value

a list of treatment parameters:

• treatment_degradation_rate = degradation rate (per time step) of chemical concentration,

• treatment_efficiency = maximal efficiency of chemical treatments (i.e. fractional reduction of pathogen infection rate at the time of application),

• treatment_timesteps = vector of time steps corresponding to treatment application dates,

• treatment_cultivars = vector of indices of the cultivars that receive treatments,

• treatment_cost = cost of a single treatment application (monetary units/ha)

• treatment_application_threshold = vector of thresholds (i.e. disease severity, one for each treated cultivar) above which the treatment is applied in a polygon.

See Also

setTreatment

Examples

treat <- loadTreatment()
treat

landsepi documentation built on July 26, 2023, 5:36 p.m.