hemc {soilphysics}

High-Energy-Moisture-Characteristics Aggregate Stability

Description

A function to determine the modal suction, volume of drainable pores, structural index and stability ratio using the high-energy-moisture-characteristics (HEMC) method by Pierson & Mulla (1989), which is used to analyze the aggregate stability. Before using hemc(), the user may estimate the parameters of the Modified van Genuchten's Model through the function fitsoilwater5().

Usage

hemc(x, theta_R, theta_S, alpha, n, b1, b2, 
	graph = TRUE, from = 1, to = 30, 
	xlab = expression(Psi ~ (J~kg^{-1})), 
	ylab = expression(d ~ theta/d ~ Psi), ...)

Arguments

x

a vector containing matric potential values.

theta_R

a numeric vector of length two containing the parameter values in the following orde: fast and slow.

theta_S

a numeric vector of length two containing the parameter values in the following orde: fast and slow.

alpha

a numeric vector of length two containing the parameter values in the following orde: fast and slow.

n

a numeric vector of length two containing the parameter values in the following orde: fast and slow.

b1

a numeric vector of length two containing the parameter values in the following orde: fast and slow.

b2

a numeric vector of length two containing the parameter values in the following orde: fast and slow.

graph

logical; if TRUE (default), a graphical solution is shown).

from

the lower limit for the x-axis

to

the lower limit for the x-axis

xlab

a label for the x-axis

ylab

a label for the y-axis

...

further graphical arguments

Value

A list of a two objects: 1) a matrix containing the Modal Suction, the Volume od Drainable Pores (VDP) and the Structural Index for both, fast and slow wetting; and 2) the value of Stability Ratio.

Author(s)

Anderson Rodrigo da Silva <[e-mail]>

References

Pierson, F.B.; Mulla, D.J. (1989). An Improved Method for Measuring Aggregate Stability of a Weakly Aggregated Loessial Soil. Soil Sci. Soc. Am. J., 53:1825–1831.

See Also

fitsoilwater5

Examples

hemc(x = seq(1, 30), theta_R = c(0.27, 0.4), theta_S = c(0.65, 0.47), 
	alpha = c(0.1393, 0.0954), n = c(6.37, 7.47), 
	b1 = c(-0.008421, -0.011970), b2 = c(0.0001322, 0.0001552))

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