envalysis (version 0.3.3)

texture: ASTM soil texture analysis

Description

Calculates the particle size distribution and both DIN and USDA texture classes from a series of hydrometer readings according to ASTM D422-63(2007)e2.

Usage

texture(time, reading, blank, temp, data, conc = 50, Gs = 2.65,
  hydrometer = "auto", model = "auto", plot = F)
# S3 method for texture
print(x, ...)
# S3 method for texture
plot(x, ...)

Arguments

time

a numeric vector or data frame object containing the time passed since the beginning of the measurement in minutes

reading

a numeric vector or data frame object providing the actual hydrometer readings at the bottom of the meniscus

blank

a numeric vector or data frame object containing the blank readings taken in 5 g/L sodium hexametaphosphate solution (composite correction)

temp

an integer vector or data frame object containing the measured temperature

data

a data frame containing the specified columns. If empty, data need to be given as numeric vectors

conc

the concentration of the soil solution, default = 50 g/L as proposed in the ASTM guideline

Gs

specific gravity of the suspension, default = 2.65

hydrometer

a character sting specifying the hydrometer used. Accepted values are "auto" for auto-detection (default), "151H", and "152H"

model

string is passed to drm, "auto" chooses the best fitting model automatically

plot

logical; if TRUE the particle size distribution is plotted

x

an object of class "texture"

…

further arguments to be passed to print or plot

Value

texture returns an object of class "texture". The functions print and plot are available to retrieve the soil texture classes and the particle size distribution, respectively.

An object of class "texture" is a list containing the following components:

meta	Measurement meta data
distribution	data.frame providing the particle size distribution
model	information on the fitted drm model
din	Main DIN texture classes
usda	Main USDA texture classes

References

ASTM D422-63(2007)e2, 2007. Standard Test Method for Particle-Size Analysis of Soils (Technical standard). ASTM International, West Conshohocken, PA. Available from http://www.astm.org/Standards/D422.htm

Examples

# NOT RUN {
data(clayloam)
texture(Time, Reading, Blank, Temperature, data = clayloam)

# }