Factors in soil formation

The factors involved in soil formation are time, geology, relief, drainage, climate, vegetation and people.

Time

It takes about 1000 years for one centimetre of soil to form. In many parts of Britain we have had only 10,000 years since the last Ice Age stripped the original surface soils away.

Geology

Minerals from the parent material are added to the soil by physical and chemical weathering.

Relief

Different soils will form on different degrees of slope and aspect. Gravity and temperatures will affect the degree of slope movement and weathering.

Drainage

Whether water can or cannot move through the soil easily will affect the development of the soil profile.

Climate

How much water and air enter the soil - and their temperatures - will affect the organic life of the soil and evaporation rates on the surface.

Vegetation

The type and quantity of plant cover will affect the amount of organic material added to the soil. This is called humus.

People

When people change the angle of a slope through construction, or change the vegetation cover and/or drainage in an area, the soil will also change.

The video below shows a soil scientist explaining what soil is and what it is made from.