soil {medfate}

Soil initialization

Description

Initializes soil parameters and state variables for its use in simulations.

Usage

soil(SoilParams, VG_PTF = "Toth", W = as.numeric(c(1)), SWE = 0)

## S3 method for class 'soil'
print(x, model = "SX", ...)

Arguments

SoilParams

A data frame of soil parameters (see an example in defaultSoilParams).

VG_PTF

Pedotransfer functions to obtain parameters for the van Genuchten-Mualem equations. Either "Carsel" (Carsel and Parrish 1988) or "Toth" (Toth et al. 2015).

W

A numerical vector with the initial relative water content of each soil layer.

SWE

Initial snow water equivalent of the snow pack on the soil surface (mm).

x

An object of class soil.

model

Either 'SX' or 'VG' for Saxton or Van Genuchten pedotransfer models.

...

Additional parameters to print.

Details

Function print prompts a description of soil characteristics and state variables (water content and temperature) according to a water retention curve (either Saxton's or Van Genuchten's). Volume at field capacity is calculated assuming a soil water potential equal to -0.033 MPa. Parameter Temp is initialized as missing for all soil layers.

Value

Function soil returns a list of class soil with the following elements:

• SoilDepth: Soil depth (in mm).

• W: State variable with relative water content of each layer (in as proportion relative to FC).

• Temp: State variable with temperature (in ºC) of each layer.

• Ksoil: Kappa parameter for bare soil evaporation.

• Gsoil: Gamma parameter for bare soil evaporation (see hydrology_soilEvaporationAmount).

• dVec: Width of soil layers (in mm).

• sand: Sand percentage for each layer (in percent volume).

• clay: Clay percentage for each layer (in percent volume).

• om: Organic matter percentage for each layer (in percent volume).

• VG_alpha, VG_n, VG_theta_res, VG_theta_sat: Parameters for van Genuchten's pedotransfer functions, for each layer, corresponding to the USDA texture type.

• Ksat: Saturated soil conductivity for each layer (estimated using function soil_saturatedConductivitySX.

• macro: Macroporosity for each layer (estimated using Stolf et al. 2011).

• rfc: Percentage of rock fragment content for each layer.

• Kdrain: Saturated vertical hydraulic conductivity (mm/day) (i.e. how easy is deep drainage towards groundwater). Function soil estimates it as a function of soil saturated hydraulic conductivity, but should be parametrized as a function of bedrock material.

Author(s)

Miquel De Cáceres Ainsa, CREAF

References

Carsel, R.F., and Parrish, R.S. 1988. Developing joint probability distributions of soil water retention characteristics. Water Resources Research 24: 755–769.

Tóth, B., Weynants, M., Nemes, A., Makó, A., Bilas, G., and Tóth, G. 2015. New generation of hydraulic pedotransfer functions for Europe. European Journal of Soil Science 66: 226–238.

Stolf, R., Thurler, A., Oliveira, O., Bacchi, S., Reichardt, K., 2011. Method to estimate soil macroporosity and microporosity based on sand content and bulk density. Rev. Bras. Ciencias do Solo 35, 447–459.

See Also

soil_psi2thetaSX, soil_psi2thetaVG, spwb, defaultSoilParams

Examples

# Initializes soil
s = soil(defaultSoilParams())

# Prints soil characteristics according to Saxton's water retention curve
print(s, model="SX")

# Prints soil characteristics according to Van Genuchten's water retention curve
print(s, model="VG")