Soil Texture Triangle
Guide to Soil Textures by Feel
Northwestern Guide to Soil Textures
(modified from Rob Harrison’s figure)
(works best when utilized with adequate beer intake)
Start Here
p lace ap p roximately 10 g soil in p alm,
add water drop wise and knead the soil
to break down aggregates. Soil is at
the p rop er consistency when p lastic
and moldable like moist p utty .
add dry soil to
soak up water
ya
sure
does soil remain in a
ball when squeezed?
ya
sure
no
ya
sure
is soil
too dry ?
no
is soil
too wet?
S AND
no
p lace a ball of soil between thumb and forefinger
gently p ushing the soil with the thumb and
squeezing it up ward into a ribbon. Form a ribbon
of uniform thickness and width. Allow the ribbon
to emerge and extend over the forefinger,
breaking from its own weight
does the soil even form a ribbon?
no
you
betcha
does soil make a
weak ribbon less
than 2.5 cm long
before
breaking?
ya
no
sure
LOAMY
S AND
does soil make a
medium ribbon less
than 2.5 -5 cm long
before ya
breaking?
no
does soil make a
strong ribbon 5 cm
or longer before
breaking? ya
sure
sure
excessively wet a small p inch of soil in p alm and rub with forefinger
does soil
ya
ya
feel very sure
sure
gritty ?
S ANDY
LOAM
no
does soil
ya
feel very sure
gritty ?
S ANDY
CLAY
LOAM
does soil
ya
ya
feel very sure
sure
gritty ?
no
does soil ya
ya
feel very sure
sure
smooth?
S ILTY
LOAM
no
no
does soil
ya
feel very sure
smooth?
no
smoothness or grittiness don't dominate;
is sticky
ya
sure
LOAM
S ANDY
CLAY
S ILTY
CLAY
LOAM
smoothness or grittiness don't dominate;
is sticky ya
does soil ya
ya
feel very sure
sure
smooth?
no
smoothness or grittiness don't dominate;
is sticky ya
sure
sure
RobHarrison:NW guide to soil texture
CLAY
LOAM
S ILTY
CLAY
CLAY