swissforestsoils {soilhypfit}

Physical properties of Swiss forest soils

Description

The data give basic physical properties, water content and hydraulic conductivity measurements (at given capillary pressure head) for 128 soil layers (horizons) measured at 23 forest sites in Switzerland.

Usage

data(swissforestsoils)

Format

A data frame with 1373 observations on the following 21 variables.

profile_id

a factor with short labels for the 23 sites.

profile

a factor with with long labels for the 23 sites.

longitude

a numeric vector with the latitude of the site in degree.

latitude

a numeric vector with the latitude of the site in degree.

layer_id

a factor with labels for the 128 soil layer.

layer_ub, layer_lb

numeric vectors with the upper and lower depth (unit cm) of the soil layer for the measurements of the basic physical properties (particle_density, ..., ksat).

particle_density

a numeric vector with the density of the solid soil material (unit \mathrm{g} \,\mathrm{cm^{-3}}).

bulk_density

a numeric vector with soil (bulk) density (unit \mathrm{g} \,\mathrm{cm^{-3}}).

porosity

a numeric vector with the soil porosity (unit volume percentage).

clay

a numeric vector with the clay content (unit mass percentage).

silt

a numeric vector with the silt content (unit mass percentage).

sand

a numeric vector with the sand content (unit mass percentage).

ksat

a numeric vector with the saturated hydraulic conductivity (unit \mathrm{m} \,\mathrm{d^{-1}}).

head

a numeric vector with capillary pressure head at which theta (water retention curve) and/or ku (hydraulic conductivity function) were measured (unit m).

layer_ub_theta, layer_lb_theta

numeric vectors with the upper and lower depth (unit cm) of the soil layer for which the water retention curve was measured.

theta

a numeric vector with volumetric water content measurements (dimensionless) of the water retention curve.

layer_ub_ku, layer_lb_ku

a numeric vector with the upper and lower depth (unit cm) of the soil layer for which the water retention curve was measured.

ku

a numeric vector with hydraulic conductivity measurements (unit \mathrm{m} \,\mathrm{d^{-1}}) of the hydraulic conductivity function.

Details

clay, silt and sand refer to soil particles with diameter less than 2, between 2 and 50 and larger than 50 \mum.

Source

Richard, F. & Lüscher, P. 1978 – 1987. Physikalische Eigenschaften von Böden der Schweiz. Lokalformen Bände 1 – 4. Eidgenössische Anstalt für das forstliche Versuchswesen, Birmensdorf.

Examples

# use of \donttest{} because execution time exceeds 5 seconds

# estimate parameters using all samples (samples with water retention,
# hydraulic conductivity, or with both type of measurements)

data(swissforestsoils)

# define number of cores for parallel computations
if(interactive()) ncpu <- parallel::detectCores() - 1L else ncpu <- 1L

# unconstrained estimation (global optimisation algorithm NLOPT_GN_MLSL)
r_uglob <- fit_wrc_hcc(
  wrc_formula = theta ~ head | layer_id,
  hcc_formula = ku ~ head | layer_id,
  data = swissforestsoils,
  control = control_fit_wrc_hcc(
    settings = "uglobal", pcmp = control_pcmp(ncores = ncpu)))
summary(r_uglob)
coef(r_uglob)