Question

How is soil formed short points for class 9

Answer 1

Soil is the uppermost layer of landmass of the Earth. It is a life supporting medium, in which plants can grow. It is soft and porous in nature and contains enough nutrients and water for the growth of plants.Most of the landmass of the Earth is not covered with soil.

Soil has been formed from the parent rock material over millions of years. This process by which soil formation takes place is called weathering. So, Weathering is a very slow and gradual process during which parent rock material breaks down into fine particles.

Answer 2

Various physical, chemical and some biological processes break down the rocks over a period. The products are the fine particles of soil. There are many other factors, which play a vital role in the formation of soil.

These factors are :

(i) The Sun : It causes heating of rocks resulting in cracks and ultimately breaking down into smaller pieces.

(ii) Water: It breaks rocks by both freezing and their speed of flow.

(iii) Wind: It causes erosion of rocks similar to the action done by fast flowing water. It also carries sand from one place to the other like water does.

(iv) Living organisms: Lichens and moss plants grow on the rock surface and cause rock surface to powder down and form a thin layer of soil