LaMotte Soil Texture - Manual (Page 6)

4. Cap and shake for 2 minutes. (Figure 2)
5. Allow the tube to stand undisturbed for
30 seconds
.
6. Place plastic ruler next to tube. (Figure 3)
Measure the height of the particles that have
settled. This is the sand portion of the soil.
This is Reading B.
Percent Sand =
Reading B x 100
Reading A
7. Allow tube to stand undisturbed for 30
minutes.
8. Use the ruler to measure the total height of
the particles that have settled. This is
Reading C.
9. Subtract the sand height (Reading B) from
total height of the soil that has settled
(Reading C). This represents the silt portion
of the soil.
Percent Silt =
(Reading C - Reading B) x 100
Reading A
10. Subtract the Percent Sand and the Percent
Silt from 100%. This is the Percent Clay.
Percent Clay = 100% - Percent Sand - Percent Silt
For example:
Initial amount of soil: Reading A = 1.35 cm
After 30 seconds: Reading B = 0.80 cm
After 30 minutes: Reading C = 1.30 cm
Percent Sand =
0.80 cm x 100
= 59%
1.35 cm
Percent Silt =
(1.30 cm - 0.80 cm) x 100
= 37%
1.35 cm
Percent Clay = 100% - 59% - 37% = 4%
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