Soil Water

Soil water is mainly found within the pore spaces of the soil. It competes with air for pore spaces and therefore occupies the pore spaces not occupied by soil air. It is also found in the spaces between the mineral grains of the soil.

Organic Matter

Soil organic matter is an important component of soils; although it constitutes only about 5% of total soil composition of mineral soils (it could constitute as much as 95% in organic soils like peat, muck etc). Along with mineral matter, it constitutes the soil solids.

Mineral Matter

Mineral matter is the predominant component of mineral soils. It constitutes about 45% of total soil composition. It is made up of a number of particles which vary in size, shape and chemical composition. These particles range from the microscopic colloidal clays to the coarse fraction of sand and gravel. In nature, mineral matter exists as a dispersed phase, implying that it can be separated into the individual particles that comprise it. Along with soil organic matter, it makes up the solid materials phase of the soil.

Soil Air

Soil air is an important component of soils. It occupies those pore spaces not occupied by soil water. Soil air competes with soil water for the pore spaces in the soil, hence it moves in as water moves out.

Composition Of The Soil

Mineral soils are broadly divided into solid materials and pore spaces. The solid materials are further divided into mineral matter and organic matter, while the pore spaces are made up of air and water. Therefore the four major components of the soil are: