What is Soil ? Its Definition, Properties & Features

Soil is the surface layer of the earth’s land mass that is soft and particulate in nature.

It is the very base on which plants and trees grow, and we raise crops for food.

Besides, it is also a dwelling home for many microbes, insects, mollusks, reptiles, birds, and animals on the land.

So, the importance of soil directly relates to the survival of all living beings.

If you are born and brought up in cities, the chances of visibility of soil daily would be minimal due to heavy deforestation.

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 to the environment.

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

The soil has many more 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 the 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’s crust. It is of considerable thickness and can be classified into different soil layers.

What is Soil

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

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

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

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

♠ Based on diameter, the 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 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 require both water and air.

♠ Humus increases soil porosity and the water-retaining capacity of the soil. It is formed due to the decomposition of the dead remains of organisms. Also, the soil microbes keep rich in 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. In comparison, nitrogen-fixing bacteria take nitrogen from the atmosphere and fix it in the soil as ammonia.

Due to these vast features and advantages, soil sustains the growth of plants, the 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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