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LaMotte SOIL TEXTURE UNIT 1067 User Manual

Page 2

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3. Use the pipet (0372) to add 1 mL of *Texture Dispersing Reagent

(5644PS) to the sample in Soil Separation Tube “A”. Dilute to line

45 with tap water.

4. Cap and gently shake for two minutes, making sure the soil sample

and water are thoroughly mixed.

The sample is now ready for separation. The separation is accomplished by

allowing a predetermined time for each fraction to settle out of the

solution. Be sure that you continue to gently shake the separation tube up

to the time of the first separation (Step 5).
5. Place Soil Separation Tube “A” in the rack. Allow to stand

undisturbed for exactly 30 seconds.

6. Carefully pour off all the solution into Soil Separation Tube “B”.

Return Tube “A” to the rack. Allow Tube “B” to stand undisturbed for

30 minutes.

7. Carefully pour off the solution from Soil Separation Tube “B” into

Soil Separation Tube “C”. Return Tube “B” to the rack.

8. Add 1 mL of Soil Flocculation Reagent (5643PS) to Soil Separation

Tube “C”. Cap and gently shake for one minute.

9. Place the Soil Separation Tube “C” in the rack and allow to stand

until all the clay in suspension settles. This may require up to 24

hours.
NOTE: Unless there is further use of the clay sample for air drying and study

as described later, it is not necessary to wait for the suspension to settle.

Due to the colloidal nature of clay in solution and its tendency to swell

and form a gel, the portion of clay remaining in Tube “C” is not used to

determine the clay fraction present in the soil. The clay fraction is

calculated by adding the sand and silt fractions and subtracting this total

from the initial volume of soil used for the separation.
EXAMPLE:

Tube “A” Sand

2

Initial Volume

15

+Tube “B” Silt

+8

Total “A” & “B” -10

Total “A” & “B” 10

Clay

5

10. Read Soil Separation Tube “A” at top of soil level. To calculate

percentage sand in the soil, divide reading by 15. Multiply by 100.

Record as % sand.

11. Read Soil Separation Tube “B” at top of soil level. To calculate

percentage silt in the soil, divide reading by 15. Multiply by 100.

Record as % silt.