What is Soil ? Its Definition, Properties & Features

What is Soil?

The soil is the basic unaltered form of surface earth which we can feel by our feet.

In practical terms, it is the very base due to which humans get food by crops. And plants and trees get the support to stand erect on the earth.

On the other hand, it is also a dwelling home for a vast number of insects, mollusks, reptiles and even birds on the earth.

So the importance of soil relates to the very survival of all the living beings on the earth.

Due to the growth of cities, urbanization and deforestation, chances of visibility of soil daily has been lost.

The feel of the soil is immense and heart touching. Walking by foot on soil reduces mental stress. It enhances blood flow to the soles and thereby brings a natural feel of the environment.

But, it seems there are millions of people whose feet have not felt the touch of the soil .:-)

The soil has many uses to man than any other living being.

Below we see the definition, properties and features of soil

Soil definition:

The soil is the loose superficial layer of earth’s crust mingled with organisms, water and air forming a thin layer on land surface ranging from few feet to meters in thickness.

Properties of soil & its features:

♠ The soil is the uppermost layer of the earth crust. It is of considerable thickness and can be classified into different soil layers.

♠ The three soil layer are classified as A-horizon, B-horizon, C-horizon. A-horizon is suitable for plant growth due to high fertility. B-horizon holds water while C-horizon is of rock and is less suitable for plant growth.What is Soil

♠ Soil readily absorbs water. This is due to porous spaces between the soil particles. Also, the absorbed moisture stays for long due to biological habitat there. There are microbes, and plant flora which keeps the soil biology in-tact.

♠ The depth of soil getting wet rises with the length of raining. If the time of the rain is short, the thickness of soil which gets wet is low. So rains with long duration are better for wetting the soil and also raise groundwater levels.

♠ Soil entrapped air has high concentration of CO2 and low concentration of O2. In water stagnant soil, O2 concentration is even lower.

♠ Based on diameter, soil is classified as coarse gravel, fine gravel, coarse sand, fine sand, silt and clay.

♠ Water from the soil is available to the plants by capillary action. The more deeper the roots penetrate, the more is the supply of moisture.

♠ Loam soil is most suitable for plant growth due to optimal aeration and water holding properties. Since seed germination and growth requires both water and air.

♠ Humus increases soil porosity and water retaining capacity of soil. It is formed due to decomposition of dead remains of organisms. Also the soil microbes keep the rich with porosity and air.

♠ Soil microbes especially saprophytic (eats decaying matter) and nitrogen-fixing ones are beneficial to soil fertility. Saprophytes decay any dead organism on the soil surface.  While nitrogen-fixing bacteria take nitrogen from atmosphere and fix it in soil as ammonia.

Due to these vast features and advantages, soil sustains the growth of plants, breeding of birds and the existence of ecosystems. It is also the very base for agriculture and forests. So without soil, all the above benefits are lost. Hence we need to conserve the soil for future life.

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