Chemical and Biological Composition (Components) of Soil

Topic Content:

Mineral or Inorganic matter, organic matter, and water are collectively referred to as chemical components of the soil while living organisms are referred to as biological components of the soil.

This percentage of soil components can also be represented by a pie chart as shown below:

Mineral or Inorganic Matter:

This constitutes small rock fragments of the soil. It forms the total bulk of about 25% of the total volume of the soil. It consists of gravel, stones, sand, silt and clay.

Importance/Effects of Inorganic Matter on Agriculture:

• Affects soil porosity.
• Forms the solid part of the soil and provides support for plants.
• It is the main source of plant nutrients such as nitrogen, calcium, Iron and magnesium.
• Represents the habitat of all living organisms.
• Holds water and air for both plant and animal activities.
• Has minimal effects on soil temperature.

Organic Matter:

Represents the remains of the decomposition of plants and animals. It is about 5% of the total volume of the soil. Leaves, roots of plants, the residue of crops, and animal dung when deposited on the soil, decay to form