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One of the most popular home tests for
measuring the percentage of sand, silt, and clay
involves nothing more sophisticated than a quart or
litre glass jar with lid and a ruler. It is based on the
rate these different particle types settle in water. The
large, boulder shaped sand particles settle the fastest,
followed by the smaller particles of silt, and then
followed by the very small and flattened particles of
clay.
Collect about 2 cups (500 ml) of soil to
be tested and pick out the bulk of the organic matter.
Let the sample dry in the sun and break up any clumps by
tapping with a hammer. Put about 3/4 cup (200 ml) of the
soil sample into the glass jar, fill almost to the top
with water, cap the jar and shake vigorously for five
minutes.
Let the jar sit undisturbed for 24
hours and measure the depth of the settled soil with the
ruler. This is the total amount of soil particles. Shake
the jar again for an additional 5 minutes and allow it
to stand for 40 seconds. Measure the settled soil. This
is the amount of sand in the sample.
Keep the
jar undisturbed and measure the settled soil at the end
of 30 minutes. This is the amount of sand and silt
together. Subtract the amount of sand from that total
for the amount of silt. Subtract the amount of sand and
silt together from the total amount of soil particles to
obtain the amount of clay.
Percentage of sand =
(depth of sand/total depth) * 100
Percentage of silt
= (depth of silt/total depth) * 100
Percentage of
clay = (depth of clay/total depth) * 100 |