psd2classUS: Generate USDA texture class

In melwey/euptf: Hydraulic pedotransfer functions for Europe

Generate USDA texture class

Description

Generate USDA soil texture class from sand, silt, clay content, and organic carbon content to distinguish organic soils.

Usage

psd2classUS(sa, si, cl, oc = NULL, option = FALSE, tol=1)

Arguments

sa	numeric vector of N observations of sand content in mass percent. Particles of diameter between 0.05 and 2 mm.
si	numeric vector of N observations of silt content in mass percent. Particles of diameter between 0.002 and 0.05 mm.
cl	numeric vector of N observations of clay content in mass percent. Particles of diameter less than 0.002 mm.
oc	optional numeric vector of N observations of organic carbon content in mass percent. Determined by dry combustion after removal of carbonates or harmonised to that method.
option	logical. If FALSE (default), the output will be returned as a numeric vector. If TRUE, the output will be returned as a character vector.
tol	numeric setting the tolerance on the sum of sand, silt, clay. Default is 1: sum(sand,silt,clay) > 101 or < 99 will return NA.

Details

Codes used for the textural classification:

1=C (Clay)	5=CL (Clay Loam)	9=L (Loam)
2=SiC (Silt clay)	6=SCL (Sand Clay Loam)	10=SL (Sand Loam)
3=SC (Sand Clay)	7=Si (silt)	11=LS (Loam Sand)
4=SiCL (Silt Clay Loam)	8=SiL (silt Loam)	12=S (Sand)
13=O (organic)

Organic soils are defined as soils having clay content >= 60 % clay and organic carbon >= 18 % , or having clay content < 60 % and organic carbon >= (12+clay*0.1).

Value

A numeric or character vector of length N with USDA texture class for each observation.

Author(s)

M. Weynants

References

E. Benham, R.J. Ahrens, W.D. Nettleton. MO5 Soil Technical Note-16. March 19, 2009. Subject: SOI – Clarification of Textural Class Boundaries. National Soil Survey Center, USDA-NRCS, Lincoln, Nebraska

IUSS Working Group WRB. 2006. World reference base for soil resources 2006. World Soil Resources Reports No. 103. FAO, Rome

See Also

psd2classFAO_MOD, TT.points.in.classes

Examples

data(ptf.data)
ptf.data$TEXT_US <- psd2classUS(ptf.data$USSAND,ptf.data$USSILT,ptf.data$USCLAY,ptf.data$OC,option=TRUE)

melwey/euptf documentation built on Sept. 17, 2022, 3:35 a.m.