Ecology is the scientific study of the relationships between organisms and their environment. An ecosystem is all of the organisms in a given place in interaction with their nonliving environment.
The soil is a thriving ecosystem of plants and animals which play an important role in the soil. Both plants and animals change the composition and structure in many different ways.
Plant roots get energy to grow from sugars through the photosynthesis process that occurs in it's leaves. they move through the soil with great force wedging their way between soil particles. A root is strong enough to even fracture rock if it grows into a crack. Once in place, soil nutrients and water are absorbed, sometimes from great depths and moved closer to the surface.
The plant uses most of what it has collected by the roots to grow larger and produce seed such as wheat that we use to make bread. As the plant dies, the remaining nutrients are used by another plant during the following growing season.
For all the plant mass you see above ground, there is an equal or greater mass of roots growing beneath the surface.
The soil is teaming with animals. Some are seen like earthworms, ants, and burrowing animals. Others such as bacteria, fungi, and nematodes may require a microscope to see the individual members.
The earthworm is a good animal to examine closer. There may be as much as 200 to 1,000 pounds of earthworms per acre. They eat organic matter and soil particles as they tunnel through the soil. They digest the organic matter and pass nutrient-rich soil through their bodies. This recycles nutrients and makes soil rich. In addition, their tunnels allow air and water to penetrate the soil more rapidly.
Note: This page was developed from information found in a USDA, Soil Conservation Service (now, Natural Resources Conservation Service) publication, "Conserving Soil".