Soil Profile : Definition, Full details of soil layers

Soil Profile : Definition, Full details of soil layers

The view from a lateral section of soil outlines the soil from which the layers involved in the formation of solid rock can be seen. The process of soil formation directly develops the soil. As we go deeper into the soil, the color of the soil changes, similarly the shape of the rock pieces also changes. To see this change, you can dig a pit in your garden or visit a place where excavation work is going on. Here you will get to see the layered structure of the soil. Such a view of soil is called soil profile.

The vertical section of soil which shows its various layers is called Soil profile.

Soil generally has three layers. Each layer is called a bed or horizon. The details of these three layers are as follows-

Top Soil or A-horizon

• The uppermost layer of the soil is called the A-horizon. It is also called Top soil. It is usually dark in colour. It contains fine particles of stone, it is rich in humus, which is formed by the decomposition of dead plants and animals. It makes the soil fertile. This is how plants get the nutrients they need. It is full of organic matter and plants have roots inside it and many micro-organisms also live in this layer. The soil in this layer is soft porous and has the capacity to hold more water.

Subsoil or B-horizon

• Just below the upper soil there is a B-horizon layer, it is called Subsoil. This layer of soil is harder and more dense than the top soil. It contains less amount of humus and organic matter than the upper soil, but soluble mineral salts and iron oxide remain in abundance in this layer. Due to the presence of these minerals, its color is red or brown. It consists of sand stone powder and small pieces. Rain water also collects in this surface. Due to the long roots of some trees, they reach this surface. This surface is found in less amount of organic matter, so it is not suitable for the growth of plants.

Different layers seen in the soil section

The parent rock or C-horizon

• This is the lowest layer of the soil, it is called the parent rock or sub-layer. This layer is just below the subsoil layer. In this layer there are small pieces of stone and fissured and jointed rocks. It lacks organic matter, but some minerals are found in this layer. In this region, the broken pieces of rocks form the land.

Bed rock

• Beneath the parent rock is a thick layer of solid rock called the bedrock. There are no holes in it. It is here that rain water and water get collected. This is the basis of the outline of the land.