Soil | Introduction
Introduction
Commonly called dirt, soil is a central ingredient for life on Earth. Soil is the thin, outer layer of material on the surface of Earth, ranging from a fraction of an inch to several feet thick.
Plants depend on soil for their nutrients and growth. These plants are then consumed and used by animals, including people. Soils provide shelter and a home for insects and small animals. Microscopic organisms flourish in soil, breaking down dead matter, which returns nutrients into the soil for new life. People use soils directly as a material to build on and grow crops in. Soils also reveal a historical record of an area's past life and geography. Understanding the properties of a soil is a key to determining how the soil will function for a particular use.
The specific makeup of soil depends on its location, yet all soils share the same basic composition: minerals, water, air, and organicMade of, or coming from, living matter. matter, meaning matter that contains carbon and comes from living organisms. Minerals are naturally occurring inorganic or nonliving substances that come from Earth's crust. Different types and combinations of these components form multiple types of soil. In the United States alone, researchers have identified over seventy thousand different soils. Soils are characterized by many features, including their structure, texture, living organisms, and acidity.