The United States Department of Agriculture (USDA) has a soil classification system that recognizes 12 different orders of soil, each with its own unique properties and characteristics. These orders are as follows:

1. Alfisols: These soils are typically found in temperate regions and have a high base saturation. They are often used for agriculture.

2. Andisols: These soils are formed from volcanic ash and are found in areas with high levels of volcanic activity. They are typically dark and fertile.

3. Aridisols: These soils are found in dry regions and have a low water content. They are often saline or alkaline.

4. Entisols: These soils are young and have not yet developed distinct horizons. They are often found in areas that have been recently glaciated or disturbed.

5. Gelisols: These soils are found in cold regions and are subject to freezing and thawing. They are often found in polar regions.

6. Histosols: These soils are formed from organic matter and are found in wetlands and other areas with high water content.

7. Inceptisols: These soils are young and have not yet developed distinct horizons. They are often found in areas that have been recently glaciated or disturbed.

8. Mollisols: These soils are found in temperate regions and have a high base saturation. They are often used for agriculture.

9. Oxisols: These soils are found in tropical and subtropical regions and have a low base saturation. They are often acidic and infertile.

10. Spodosols: These soils are found in temperate and boreal regions and have a high accumulation of organic matter in the subsoil. They are often acidic and infertile.

11. Ultisols: These soils are found in tropical and subtropical regions and have a low base saturation. They are often acidic and infertile.

12. Vertisols: These soils are found in tropical and subtropical regions and have a high content of clay. They are often sticky and difficult to work.