What is soil? How does it form?

The topmost layer of earth’s crust that supports life forms is known as soil. Soil decides the diversity of soil in a area. Soil is formed by Weathering of rocks by mechanical, biological and chemical processes.

● Physical/Mechanical- Breakdown of rocks into smaller pieces. The rocks get heated up during the day and it cools down during night. This expansion and contraction due to heating and cooling of rocks lead to splitting of rocks. Water might enter the rocks in the cracks made by expansion and contraction. When this water freezes, the rocks widen and thus rocks break.

● Chemical- it occurs when rocks are worn away by chemical changes like the chemicals released by lichens. These chemicals cause the rock surface to powder own which forms layers of soil

● Biological- Disintegration of rocks by activities of living organisms like plant grow in the cracks of rocks thus breaking the rocks