How Soils Form Image: T. Loynachan Soils-2-1

Physical weathering breaks rocks into small mineral particles that accumulate on the Earth’s surface. Images: Martin Miller, NRCS Soils-2-2

Chemical weathering dissolves and changes minerals that have accumulated on the Earth’s surface. Images: National Cooperative Soil Survey, University of Nebraska Soils-2-3

Decomposing organic material from plants and animals mixes with accumulated soil minerals. Images: NRCS, Soil Classifiers of Michigan Soils-2-4

Accumulated soil materials contain voids filled with air or water. Image: T. Loynachan Soils-2-5

Continued physical and chemical changes over hundreds to thousands of years produce layers called soil horizons. Image: National Cooperative Soil Survey Soils-2-6

The Formation of Soils Image: T. Loynachan