Soil

Pedologists, or soil scientists, define soil in general terms this way: the naturally occurring unattached mineral or organic material at the earth's surface that is capable of supporting plant growth. Soil is a complex biological system that has developed in Alberta since the last glaciation 10,000 years ago. Soil formation is a continuous, but slow, process. The productive portion of the soil is the topsoil, a relatively thin veneer of well-structured soil containing essential nutrients, microbes and organic matter needed to support vigorous plant life. It can take more than 100 years for one centimetre of topsoil to form. This thin layer is the foundation of all terrestrial life. Soils also help to determine how the land is used.

The composition of soil can vary widely, but it is usually a mixture of mineral particles (sand, silt and clay), organic remains in various stages of decomposition, water, air and a wide variety of living organisms. The community of organisms that live below the surface is vital to the condition of soil. These organisms (for example, beetles, worms, mites, fungi, algae, and bacteria) break down and mix the organic matter in the soil. They also help aerate the soil as they move through it. These organisms are important nutrient recyclers, decomposing organic matter and returning its nutrients to the soil.