Soil Texture Triangle
As you learned in the activity, the percentage of sand, silt and clay in the soil combine to make a variety of textural classes. How can you tell if your soil is clay loam, loamy sand, or silty clay? The soil texture triangle can help you do just that, once you know how to use it!
First, let’s break down the triangle:
- The left side of the triangle shows the percentage of clay, increasing from 0-100 as you go up
- The right side of the triangle shows the percentage of silt, increasing from 0-100 as you go down
- The bottom side of the triangle shows the percentage of sand, increasing from 0-100 as you go from right to left
- In the middle, you will see the 12 textural classes
Now, use each percentage of sand, silt and clay to determine the textural class. For this example, we will assume you have soil that’s 60% clay, 20% silt and 20% sand.
- Find the number 60 on the left side of the triangle (clay percentage). Draw a line from 60 that is parallel to the bottom of the triangle.
- Find the number 20 on the right side of the triangle (silt percentage). Draw a line from 20 that is parallel to the left side of the triangle.
- Finally, locate the number 20 on the bottom of the triangle (sand percentage). Draw a line from 20 that is parallel to the right side of the triangle.
- Wherever the 3 lines intersect will determine the textural class of your soil. In this example, the soil is classified as clay!
