Dirt, or soil, is a complex mixture of various components that provide a foundation for plant growth and support ecosystems.

An ideal soil contains 25 percent air, 25 percent water, 45 percent mineral material and 5 percent organic matter. ... If a soil lacks any of these components, plant growth is limited.

The mineral components of soil are divided into three groups according to texture, which in turn is determined by particle size. Large mineral particles, those between 0.05 and 2.00 millimeters ...

Organic matter in soil consists of both living and nonliving material. The living organic matter is made up of bacteria, fungi, and plant roots. Nonliving organic matter consists of plant ...

Salts are natural components of soil, surface, and groundwater. They are ionic mineral compounds, which means they bonded by electrostatic attractions between cations (+ charge) and anions (- charge).