The O horizon

This is the top layer of the soil, and it is composed of organic matter such as leaves, twigs, and dead plants. This layer is important because it provides nutrients for the plants that grow in the soil.

The A horizon

This layer is located below the O horizon and it is composed of minerals and organic matter. This layer is also important because it provides nutrients for plants, and it helps to hold water and air in the soil.

The B horizon

This layer is located below the A horizon and it is composed of minerals such as clay, silt, and sand. This layer is important because it helps to hold water and nutrients in the soil.

The C horizon

This layer is located below the B horizon and it is composed of unweathered rock. This layer is important because it provides a source of minerals for the other layers of the soil profile.

The R horizon

This layer is located below the C horizon and it is composed of solid rock. This layer is important because it provides support for the other layers of the soil profile.

The fifth layer is the D layer which is sometimes referred to as a hardpan. It is a dense, compacted layer of soil that can restrict the movement of water and roots.