Soil is a medium for plant growth that provides both nutrients and shelter for wide variety of organisms such as bacteria, fungi, worms and insects.

Soil formation and composition

Soil is formed from rocks which have been broken up by various physical and chemical processes or weathering.

Physical weathering, can take place as rock freezes, expands and then winded further by the pressure of plant roots.

Chemical weathering, takes place by rain water that removes soluble substance from rock, and reduces them in to smaller fragments.

Soil is composed of a complex mixture of organic and inorganic materials. Actually, soils vary in their composition.

• Mineral particles of different size
• Water
• Air
• Dissolved mineral salts
• Humus
• Microorganisms and other soil dwelling organisms