• Written By Pavithra VG

Soil: Formation, Composition, Profile, Types, Uses, Erosion, etc

Farmers’ friend is a metaphor for earthworms, which are found in Soil. Is there any other organism in the soil? What is the life cycle of these creatures in the soil? What is the soil’s composition? All of these questions will be answered in this post, dirt. This page will teach you everything you need to know about soil profiles, types of soil, uses, soil erosion, soil preservation, soil pollution, and much more.

The loose surface material that covers the majority of the land is known as soil. Soil provides structural support for agricultural plants as well as a source of water and nutrients. It is made up of both inorganic and organic particles. The chemical and physical qualities of soils vary widely. Continue reading to know complete details on Soil.

What is Soil?

One-fourth of the earth’s surface is covered with land, and the remaining three-fourth is by water. Soil is an important natural resource. The uppermost layer of the earth’s crust is called the soil. It is porous and soft in nature.

How is Soil Formed?

The soil formation results from the weathering of rocks by wind, water and climate. Weathering means the gradual breakdown of rocks into smaller components through the action of natural forces like water, air, temperature, wind, the roots of plants and mechanical collisions.

What is the Composition of the Soil?

Soil is different at different places. Some common components present in all the soils are rock and soil particles, minerals, water, air, soil organisms like fungus, microbes, worms, insects, humus, etc.

Soil Profile

The vertical section of the soil showing the different layers or horizons of soil is called a soil profile. The various layers can be easily identified by the soil’s colour and nature of particles.

Horizons of Soil

Based on the physical, chemical, and biological properties, the soil is classified into various horizons represented by the letters: $${\rm{O}},{\rm{A}},{\rm{B}},{\rm{C}}$$ and $${\rm{R}}$$, which are as follows:

The O-horizon – This is the topmost layer of the soil surface that is composed of organic materials such as dried leaves, twigs, grasses, dead animals, etc., that are decomposed. This horizon is more prominent in forest areas where the debris that falls from trees gets accumulated. The soil of this layer has dark brown or black colour.

The A-horizon – This is a surface horizon also known as the topsoil, consisting of minerals (sand, silt, and clay) and considerable amounts of organic matter such as humus. In this horizon, seed germination takes place and is predominantly the fertile surface layer of many soils in grasslands and agricultural lands. This layer is rich in several microorganisms such as bacteria, fungi, earthworms, etc.

The B-horizon – This is a subsurface horizon also known as subsoil and is comparatively more compact and harder than the topsoil. It contains less amount of humus, soluble minerals, and organic matter and is a site of deposition of certain minerals and metal salts. Due to the presence of clay, this layer holds more water than the topsoil.

The C-horizon – This horizon is above the bedrock known as parent rock and mainly consists of weathered and partially decomposed rock. This layer is known as parent material because the upper layers are formed from this layer only.

The R-horizon – This is the lowest layer consisting of a mass of rock such as granite, basalt, limestone or sandstone, quartz, and is known as bedrock.

What are the Types of Soil?

Based on the size of the soil particles, the soil is classified into three types, i.e., sandy soil, clay soil, and loamy. Their properties are as follows:

1. Sandy Soil

This soil has more air spaces due to bigger particles. It is highly porous and less fertile. Nearly $$2/{3^{{\rm{rd}}}}$$ of soil is sand, and $$1/{3^{{\rm{rd}}}}$$ is clay. It is not sticky hence cannot be used to make pots, bricks, toys, statues, etc.

2. Clayey Soil

This soil has small air spaces due to fine particles. Nearly $$2/{3^{{\rm{rd}}}}$$ of the soil is clay. It is more fertile due to the presence of minerals and humus. Due to its very small and densely packaged particles, it has high water retention. Because of its sticky nature. Crops that can grow well in this soil are beans, carrots, rice, etc.

3. Loam Soil

This soil has more air space than clay and less than sandy soil. Porosity is adequate for the growth of plants and has a high humus content. It has sand and silt in equal amounts, about $$2/{5^{{\rm{th}}}}$$ each, and $$1/{5^{{\rm{th}}}}$$ of the soil is clay. It is good for the cultivation of crops and gardening.

What are the Uses of Soil?

Soil is of great importance to us and to the entire living world because it supports the growth of plants. Following are some of the uses of soil.

1. Clayey soil is used to make pots, bricks, toys, statues, etc.
2. For the cultivation of crops and plant growth, soil is necessary, and it helps in the prevention of water runoff.
3. Soil-living microorganisms help to recycle nutrients from plants and animals that are dead.
4. Soil is also a living environment for several microorganisms, insects, earthworms, bacteria, fungi, etc.
5. Soil is used for construction purposes, beauty products, filtering, and purification of water.

Soil and Crops

The soil at different places is different The nature of the soil is affected at a certain point by climatic factors like precipitation, temperature, wind, etc. Based on the nature of the soil, different crops are cultivated in different areas.

A few examples of crops grown in different soil are as follow, wheat and sugarcane crops are grown in loam with more clay, maize and coarse crops are grown in almost all regions, and it grows well in old alluvial soil, millets like jowar, bajra and sorghum crops are grown in sandy regions, fruits and vegetable crops are grown in humus-rich soils, peanuts grow well in partly sandy soil, cotton grows when in black soil and sandy loam, jute and rice are cultivated in clay soils, etc.

What are the Reasons for Soil Erosion?

Gradual removal of the topsoil by the action of flowing water, wind, waves, and snow is called soil erosion. Both natural and human activities are reasons for soil erosion. Some of those factors are as follows:

1. Heavy rains and floods make the soil particles lose and lead to soil erosion.
2. Deforestation loosens the particles in the soil and leads to easy erosion of soil by wind and water. Deforestation makes the land barren, increasing the chances of flood. The areas with low vegetation suffer from more erosion of soil.
3. Poor farming methods adopted by farmers also add up to soil erosion.
4. Overgrazing by animals, construction of roads and houses have led to an increase in the pace of soil erosion.

What are the Methods of Soil Conservation?

Protection of soil against erosion and degradation is called soil conservation. Some of the steps which can help in soil conservation are:

1. Afforestation plays an important role in soil conservation. The roots of plants and trees bind the soil particles and prevent soil erosion.
2. Terrace farming is the method of farming in which farmers built steps called terraces on hillsides to prevent the top soil from being washed away.
3. Crop rotation can be used for preventing soil degradation.
4. Dams and embankments are built to control floods and thus prevent soil erosion.
5. Avoiding the overgrazing of animals and overuse of land.

What is Soil Pollution?

Contamination of soil by the presence of man-made chemicals or other undesirable substances is called soil pollution.

Some of the causes of soil pollution are:

1. Excessive use of pesticides, insecticides and fertilizers is the major cause of soil pollution.
2. Excretory products of living organisms and untreated sewage water also pollute the soil.
3. Plastic waste does not decay and hence pollutes the soil.
4. Salination degrades the quality of the soil.

How can we Prevent Soil Pollution?

1. Farmers should be encouraged to use biofertilizers, biopesticides, and fungicides.
2. Following the $${\rm{4 R}}$$ methods, i.e., reduce, reuse, recycle, and restore. Waste should be segregated, and a suitable method of disposal should be followed. garbage should be converted to compost and used as manure.
3. Measures to be taken to prevent overgrazing and overcropping as they lead to the destruction of the soil layers.

Soil Important Questions

1. Define the following terms: a) Weathering b) Humus
Ans:
a) Weathering is defined as the gradual breakdown of rocks into smaller pieces by the action of natural forces such as water, air, temperature, wind, plant roots, mechanical collision.
b) Humus is defined as an organic matter formed by the decomposition of dead and decayed matter of plants and animals by the action of microorganisms. It helps in increasing soil fertility.

2. What is the soil profile?
Ans:
The vertical section of the soil showing the different layers or horizons of soil is called a soil profile. It consists of different horizon, i.e., o-horizon (organic matter) , $${\rm{A}}$$- horizon (topsoil), $${\rm{B}}$$-horizon (subsoil), $${\rm{C}}$$-horizon (bedrock) and $${\rm{R}}$$- horizon.

3. Define soil erosion? What are the reasons for this?
Ans:
Gradual removal of the topsoil by the action of flowing water, wind, waves, and snow is called soil erosion. Some of those factors are as follows:
1. Heavy rains and floods make the soil particles lose and lead to soil erosion.
2. Deforestation loosens the particles in the soil and leads to easy erosion of soil by wind and water.
3. Poor farming methods adopted by farmers also add up to soil erosion.
4. Overgrazing by animals, construction of roads and houses have led to an increase in the pace of soil erosion.

Summary

Soil is of great importance to us and to the entire living world. In the article Soil, you have imbibed the meaning of soil, its composition, how it is formed, soil profile, and its different horizons, i.e., $${\rm{O, A, B, C, R}}$$. You can also explain the properties of different types of soil, i.e., clayey, sandy, and loamy, different uses of soil, what are the reasons for soil erosion, soil pollution and prevention methods for these in detail.

FAQs on Soil

We have provided some frequent;y asked questions here:

Q.1. What are the types of soil?
Ans:
The three types of soil are sandy soil, clay soil, and loamy soil.

Q.2. What are the uses of soil?
Ans:
Some of the uses of soil are as follows:
1. Potters, brick, toys, statues, etc. are made from clayey soil.
2. For the cultivation of crops and plant growth soil, is necessary, and it helps in the prevention of water runoff.
3. Soil is also a habitat for many microorganisms, insects, earthworms, bacteria, fungi, etc.
4. Soil is used for construction purposes, beauty products, filtering, and purification of water.

Q.3. Why are soils so important?
Ans:
Soil is important for the growth of plants and cultivation of crops since these obtain required nutrients and water from the soil. It is also a habitat for large number of microorganisms, insects, earthworms, etc.

Q.4. How do you define soil?
Ans:
The uppermost layer of the earth crust is called the soil. It consists of water, air, microorganisms, insects, humus, etc.

Q.5. How is soil Formed?
Ans:
The weathering of rocks by the action of wind, water, and climate results in soil formation. Weathering is defined as the gradual breakdown of rocks into smaller pieces by the action of natural forces such as water, air, temperature, wind, plant roots, mechanical collision.

Q.6. What is the composition of soil?
Ans:
The soil consists of rock and soil particles of different kinds and sizes, a variety of mineral salts, water, air, humus, organisms like fungus, microbes, worms, insects, etc.

Study Soil Profile Concept Here

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