Laboratory Investigation 2: Characteristics of Soil

Adapted from Applications in Biology/Chemistry, 1994:
Center for Occupational Research and Development, Waco, Texas

How can we determine the texture of a soil sample?
The following represent the Lab Procedures and Topics for Lab Reports

Table 1      Description of Collection Site
A. Date collected: __________________________
B. Collection site: ________________________________________________________
C. Slope: _______________________________________________________________
D. Amount and type of vegetation: __________________________________________
E. Moisture level: ________________________________________________________
F. How the land is being used: ______________________________________________

Laboratory Procedure:
  1. Crumble soil sample into small pieces.
  2. Spoon enough loose soil to fill pint-size bottle half full.
  3. Fill the bottle almost to the top with tap water.
  4. First cap the bottle. Be sure the cap is screwed on tightly. Shake the bottle. Dry hands before handling the bottle.
  5. Place the bottle upright on the lab table.
  6. Describe the appearance of soil sample after mixing with water. Use Data Table 2.
  7. Allow mixture in the bottle to settle until distinct layers of soil have formed beneath the water. If sample has not formed distinct layers after 30 minutes, label it and keep it until the next lab period.
  8. After the mixture has settled, hold a piece of cardboard next to the bottle. Mark short horizontal lines on the cardboard to indicate the level of each soil layer. Next to each layer write the type of soil particle found in the layer: clay, sand, silt. Measure the depth of each layer. Record data on Table 2.
  9. To discard materials do not empty directly into the sink. Use newspaper to form a funnel, pour material into a container. Cap container. Then discard.

    Table 2      Results
    A. How did sample look after being mixed with water? __________________________
    B. Total depth of soil, in mm. ___________________________

           _________ mm.sand            _________ % sand
           _________ mm.silt              _________ % silt
           _________ mm.clay             _________ % clay

    C. Soil Type ______________________________________________