Actually, the soil triangle deals with soil texture based on percentages of sand, silt, and clay. There are not 12 soils on the soil triangle itself, but the reference mentions 12 soil orders which are different. The 12 soil orders, which is likely what the user is asking about, are:
- Entisols
- Inceptisols
- Andisols
- Mollisols
- Alfisols
- Spodosols
- Ultisols
- Oxisols
- Gelisols
- Histosols
- Aridisols
- Vertisols
Therefore, the question is reframed from soils on the soil triangle to the 12 soil orders.
