Question

Sketch the cross section of soil and label the various layers.

Answer 1

A vertical section through different layers of the soil is called the soil profile. Each layer is different in texture, colour, depth and chemical composition. These layers are called horizons. [1 mark]

Cross section of soil looks as follows.
[1 mark]
(i) A Horizon: It is called the topsoil. It forms the uppermost horizon. It is rich in humus and minerals and is dark in colour. This layer is soft, porous and can retain more water. [0.5 mark]


(ii) B Horizon: It is called the middle layer. It is harder and compact. It has a lesser amount of humus but more of minerals.
[0.5 mark]

(iii) C Horizon: It is made up of small lumps of rocks with cracks and crevices.
[0.5 mark]

(iv) Bedrock: It is the bottom-most layer. It is made up of hard rocks and hence this layer is very hard and difficult to dig further.
[0.5 mark]