Question

various organisms inhabit in various layers of soil describe the layers of soil along with the types of organisms living in them ​

Answer 1

• Big rocks break down into smaller rocks by continuous action of wind and rain.
• It takes many years for these rocks to break down into smaller rocks.

• Rocks are mainly broken by two types of weathering- physical weathering and chemical weathering
• A number of natural force, called agents, work to break down the parent rock into tiny particles of soil.
• These agents include wind, water, the sun’s heat, and plants and animals.

• These pieces get further broken down to form sand and silt and, ultimately, into finer particles and the process continues.

• This process is very slow. It takes thousands of years to form a just 1 cm layer of soil.
• These fine particles form the top layer of the soil.

Soil Profile

• The soil is found in layers, which are arranged during the formation of soil.
• These layers called horizons, the sequence of layers is the soil profile. The layers of soil can easily be observed by their color and size of particles.
• The main layers of the soil are topsoil, subsoil and the parent rock. Each layer has its own characteristics.

• These features of the layer of soil play a very important role in determining the use of the soil.
• Soil that has developed three layers, is mature soil.
• It takes many years under a favorable condition for the soil to develop its three layers.
• At some places, the soil contains only two layers.
• Such soil is immature soil.

Horizons of the Soil

Soil consists of the following horizons:

1. Horizon A or Topsoil

• It is also called the humus layer, which is rich in organic material. This layer consists of decomposed material and organic matter. This is the reason, the topsoil has a dark brown color.

• The hummus makes the topsoil soft, porous to hold enough air and water.
• In this layer, the seeds germinate and roots of the plants grow.

• Many living organisms like earthworms, millipedes, and centipedes, bacteria, and fungi are found in this layer of soil.

2. Horizon B or Subsoil

• Just below the topsoil lies another layer called subsoil or horizon-B. It is comparatively harder and compact than topsoil.
• It is lighter in color than the topsoil because there is less humus in this layer.
• This layer is less organic but is rich in minerals brought down from the topsoil.
• It contains metal salts, especially iron oxide in a large proportion.
• Farmers often mix horizon-A and horizon-B when ploughing their fields.