The classification of the soil (in texture classes) is based on the percentage ratio of the following elements: sand, silt and clay. The texture of a soil expresses the size distribution of the elementary mineral particles that make up the solid matrix. For the USDA classification, the soil is classified in relation to the size (d = particle diameter) of the particles of the different elements:
- Clay (d< 0.002 mm)
- Limo (0.002< d< 0.05mm)
- Sand (0.05< d< 2 mm)
In addition to the USDA classification, there is also the ISSS classification. The relationship between the two classifications is shown in the following diagram:
ISSS land classification
In order to classify soils according to texture, the triangle of texture is generally used.
Using the triangle of weaving
Triangle of weaving
To identify the texture of a soil for which the percentages of the different components are known, carry out the following steps:
- enter with the percentage of “sand” on the “sand” side and draw a parallel to the “silt” side
- enter with the percentage of “silt” on the “silt” side and draw a parallel to the “clay” side
enter with the percentage of “clay” on the “clay” side and draw a parallel to the “sand” side
The point thus found falls within an area that identifies the name of the class to which the land belongs.
