The top loose layer of the earth’s crust is called soil. Soil formation takes because of weathering of rocks and it takes millions of years for the formation of soil. Sunlight, rain, wind and running water are the various agents of weathering which facilitate soil formation. Sandy soil, clayey soil and loamy soil are the main types of soil. The classification of soil is done on the basis of relative amount of clay and sand in the soil. The arrangement of various layers of soil at a place is called soil profile. The topsoil is usually composed of humus and is dark in colour.

Soil Quiz