What are the four layers of soil like?
The top layer is called the organic layer. This layer is about an inch thick and takes from 100 to 600 years to form. Within this layer, living things carry on with their life activities. Also in this layer are millions of dead plant and animal organisms that are slowly decomposing, or rotting, away. As these once-living things decay, the organic layer becomes rich in nutrients. If you dig more than an inch or two deep, you might be past this layer already! Section A in the diagram above is called the upper soil layer. This is where you will find many plant roots, different types of fungus, and other very tiny living things. This soil is dark in color because there is are so many chemical reactions taking place as living things grow and die. A great deal of bacteria is found in this layer. The bacteria help make chemical reactions happen so that materials of the earth can be recycled. This layer is usually about a foot deep. Section B in the diagram above is the middle soil layer. It h
