Question

soil layers are :

1. A horizon
2. B horizon
3. C horizon
4. R horizon

Instead of D horizon why it is called R horizon?

Answer 1

A vertical section through different layers of the soil is known as soil profile, while these layers are called as horizons. The uppermost horizon also known as A-Horizon or topsoil, consist of a layer of soft, porous and can retain more water. The next layer known as B-Horizon or middle layer has a lesser amount of humus but more of minerals, this layer is generally harder and more compact. The third layer is the C-Horizon which is made up of small lumps of rock with cracks and crevices. The last layer is R-Horizon or Bedrock, which is hard that cannot be dig with a spade.