Soil Groups
The differences in climate, vegetation, parent material, geology, topograph and soil age result in thousands of different types of soil around the world. These soils differ in depth, color, mineral content, acidity, texture and pore space. In the U.S. there are more than 17,000 different known types of soil! The U.S. Department of Agriculture created a taxonomy that has 12 major categories. Most soils fall into five major groups: spodosols, alfisols, mollisols, aridisols and oxisols.