soilphysics (version 2.1)

fitsoilwater2: Interactive Estimation of the Groenevelt and Grant (2004) Model Parameters

Description

An interactive graphical adjustment of the soil water retention curve via Groenevelt and Grant (2004) formula. The nonlinear least-squares estimates can be achieved taking the graphical initial values.

Usage

fitsoilwater2(theta, x, x0 = 6.653, xlab = NULL, ylab = NULL, ...)

Arguments

theta

a numeric vector containing the values of soil water content.

x

a numeric vector containing pF (pore water suction) values. See soilwater2.

x0

the value of pF at which the soil water content becomes zero. The default is 6.653.

xlab

a label for the x axis; if is NULL, the label "pF" is used.

ylab

a label for the y axis; if is NULL, the label "Soil water content" is used.

...

further graphical arguments; see par.

Value

• A plot of theta versus x and the curve of the current fitted model according to the adjusted parameters in an external interactive panel. Pressing the button "NLS estimates" a nls summary of the fitted model is printed on console whether convergence is achieved, otherwise a warning box of "No convergence" is shown.

References

Groenevelt & Grant (2004). A newmodel for the soil-water retention curve that solves the problem of residualwater contents. European Journal of Soil Science, 55:479-485.

See Also

nls, soilwater2, soilwater

Examples

w <- c(0.417, 0.354, 0.117, 0.048, 0.029, 0.017, 0.007, 0)
pF <- 0:7
fitsoilwater2(w, pF)

# End (not run)