lass3: R Estimation of the Water Retention Shape Parameters from...

In gowusu/vadose: The estimation of saturated hydraulic conductivity and soil water retention Curves in the vadose zone

Description

The function implements Lassabatere et al (2006) particle size distribution function for estimation of Water Retention curve. It also provides the parameters based on Minasny & McBratney (2007) studies.

Usage

lass3(data = NULL, D = NULL, fr = NULL, N = 0.1, M = 0.1, Dg = 0.1,
  p = NULL, S = NULL, C = NULL, ksat = NULL, group = NULL)

## Default S3 method:
lass3(data = NULL, D = NULL, fr = NULL, N = 0.1,
  M = 0.1, Dg = 0.1, p = NULL, S = NULL, C = NULL, ksat = NULL,
  group = NULL)

## S3 method for class 'lass3'
plot(x, main = "Particle Size Distribution Function",
  xlab = "Particle Diameter", ylab = "Fraction", ...)

## S3 method for class 'lass3'
coef(object, ...)

## S3 method for class 'lass3'
predict(object, D, ...)

Arguments

data	a dataframe of Particle Size Distribution. It can have column names of diameter of the particles "D" [mm], and fraction of the particles "fr" that ranges from 0-1.
D	character. The corresponding diameter in the data.
fr	character. The corresponding fraction of the particles.
N	numeric. The initial value of the shape parameter.
M	numeric. The initial value of the shape parameter.
Dg	numeric. A scale parameter
p	porosity[g/m^3]
S	The percentage of sand in the soil. This is needed if there is no data on PSD.
C	The percentage of clay in the soil. This is needed if there is no data on PSD
ksat	Saturated hydraulic conductivity. If NULL, this will be internally estimated with ksat
group	character. The name of the group variables if the data is from different areas.
x	a return object of the function.
main	Title of the plot
xlab	x label of the plot
ylab	y label of the plot
...	Any other graphical parameter
object	Model output object

Value

• PD: predicted fraction by mass of particles passing a particular diameter

• poresizeindex: pore size distribution index[-]

• D10: The diameter at which 10 per cent of the sample mass comprised of smaller particles

• D60: The diameter at which 60 per cent of the sample mass comprised of smaller particles

• sand: percentage of sand

• clay: percentage of clay

• silt: percentage of silt

• n: shape parameter of van Genuchten water retention alpha parameter

Author(s)

George Owusu

References

• Lassabatere, L., Angulo-Jaramillo, R., Soria Ugalde, J. M., Cuenca, R., Braud, I., & Haverkamp, R. (2006). Beerkan Estimation of Soil Transfer Parameters through Infiltration Experiments-BEST. Soil Sci. Soc. Am. J., 70(2), 521-532. doi: 10.2136/sssaj2005.0026

• Minasny, B., & McBratney, A. B. (2007). Estimating the Water Retention Shape Parameter from Sand and Clay Content Soil Sci. Soc. Am. J., 71(4), 1105-1110. doi: 10.2136/sssaj2006.0298N

See Also

zhuang3, zhuang4,logarithmic, logistic2, logistic3,fredlund3,fredlund4, jaky,andersson,gompertz, haverkamp

Examples

data=read.csv(system.file("ext","sys","soil2.csv",package="vadose"))
single<- subset(data, ID=="30B20_1")
mod=lass3 (data=single,p="sand",D="D",fr="Sand.")
plot(mod)

#group simulation
mod2=lass3 (data=data,D="D",fr="FractionSand",group="ID",ksat=TRUE)
mod2$coef
#generic function

gowusu/vadose documentation built on May 17, 2019, 7:59 a.m.