1. A soil profile is an exposure from the surface downward through a soil to its parent material. Soils-3-1 Image: NRCS Image: Martin Miller

2. Soil profiles generally expose three layers or soil horizons. Soils-3-2 Image: National Cooperative Soil Survey

3. The upper “A” horizon contains organic matter mixed with mineral particles. Percolating water dissolves and removes some mineral constituents from the “A” horizon. Horizon “A” Soils-3-3

4. Some constituents dissolved from the “A” horizon are deposited below in the “B” horizon. Horizon “A” Horizon “B” Soils-3-4

5. The “C” horizon is the lower soil layer developed on the underlying parent material. Horizon “A” Horizon “B” Horizon “C” Soils-3-5

6. A mature soil profile with well developed A, B, and C horizons takes hundreds to thousands of years to develop. Horizon “A” Horizon “B” Horizon “C” Soils-3-6 Image: NRCS