The USDA classifies soils into twelve types which it calls textures. This classification is based on the relative percentages of sand, silt and clay. This can be visualized by the use of the USDA Soil Textures Triangle.
(Please read disclaimer below before using this form)| Collect 2 shovels full of soil to a depth of 8-12 inches in a large bucket at the desired location. Remove all rocks and loose vegetative matter-twigs, etc. Mix up the remainder thoroughly. Place 2-4 cups of this material into a jar. Add water to completely cover. Add non-foaming detergent (dishwasher soap). Shake vigorously until the material has gone into solution. Set jar aside and allow the material to settle into distinct layers. |
![]() Figure 1 Sediment Measurement |
Using a ruler determine the location of the top of the SAND (A), the SILT (B), and the CLAY (C). Note: if any of the layers is missing use the reading from the lower sediment. The readings may be entered in either decimal or fraction notation, i.e. 2.5 or 2 1/2. Enter the values into the Classification Calculator below and click the CALCULATE button. The percentage of each material and the soil Classification will be shown. |