Soil Profile

Question 1

How long does it take to get 2-3 cm thick layer of soil?

Answer 1

Thousands of years

Question 2

What are the four distinct layers of soil?

Answer 2

Topsoil, subsoil, substratum, parent bedrock

Question 3

Describe topsoil.

Answer 3

• Topsoil refers to the uppermost layer of soil formed by deposition of sand, clay and silt.
• it contains humus
• roots of plants are confined to this layer

Question 4

Describe subsoil

Answer 4

• made from deposition of weathered rock, clay, silt and nutrients such as soluble minerals and iron oxides.
• rainwater is collected in this layer
• present below topsoil

Question 5

Describe substratum

Answer 5

• lies between subsoil and parent bedrock
• contains weathered rocks

Question 6

Describe bedrock

Answer 6

• last layer
• consists of solid, unweathered rocks