Classification Of Soil

On the basis of factors responsible for soil formation colour, thickness, texture, age, chemical & physical properties, the soil of India can be classified in different types.

Alluvial Soil

• Property: Alluvial soils are very fertile. Mostly these soils contain adequate proportion of potash, phosphoric acid and lime which are ideal for the growth of sugarcane, paddy, wheat and other cereal and pulse crops. Due to its high fertility, regions of alluvial soils are intensively cultivated and densely populated. Soils in the drier areas are more alkaline and can be productive after proper treatment and irrigation.
• Spread in India: These have been deposited by three important Himalayan river systems– the Indus, the Ganga and the Brahmaputra. These soils also extend in Rajasthan and Gujarat through a narrow corridor. Alluvial soil is also found in the eastern coastal plains particularly in the deltas of the Mahanadi, the Godavari, the Krishna and the Kaveri rivers.

Types of Alluvial Soil: Reaches of the river valley i.e. near the place of the break of slope, the soils are coarse. Such soils are more common in piedmont plains such as Duars, Chos and Terai.

Types as Per Age of Soil:

• Bangar: Old Alluvial Soil
• Khadar: New Alluvial Soil

Black Soil (Regur Soil):

• Property: The black soils are made up of extremely fine i.e. clayey material. They are well-known for their capacity to hold moisture. In addition, they are rich in soil nutrients, such as calcium carbonate, magnesium, potash and lime. These soils are generally poor in phosphoric contents. They develop deep cracks during hot weather, which helps in the proper aeration of the soil. These soils are sticky when wet and difficult to work on unless tilled immediately after the first shower or during the pre-monsoon period.
• Spread: This type of soil is typical of the Deccan trap (Basalt) region spread over northwest Deccan plateau and is made up of lava flows. They cover the plateaus of Maharashtra, Saurashtra, The alluvial soil consists of various proportions of sand, silt and clay. As we move inlands towards the river valleys, soil particles appear some what bigger in size. In the upper Malwa, Madhya Pradesh and Chhattisgarh and extend in the south east direction along the Godavari and the Krishna valleys.

Ideal Crop: Cotton hence another name black cotton soil.

Red and Yellow Soil

• Property: These soils have red colour due to diffusion of iron in crystalline and metamorphic rocks. It looks yellow when it is found in hydrated form.

• Spread: Parts of Orissa, Chhattisgarh, southern parts of the middle Ganga plain and along the piedmont zone of the Western Ghats.

Laterite Soil

• Property: Laterite has been derived from the Latin word ‘later’ which means brick. The laterite soil develops in areas with high temperature and heavy rainfall. This is the result of intense leaching due to heavy rain. Humus content of the soil is low because most of the micro organisms, particularly the decomposers, like bacteria, get destroyed due to high temperature. Laterite soils are suitable for cultivation with adequate doses of manures and fertilizers.

• Spread: Karnataka, Kerala, Tamil Nadu, Madhya Pradesh, and the hilly areas of Orissa and Assam.
• Crop: After adopting appropriate soil conservation techniques particularly in the hilly areas of Karnataka, Kerala and Tamil Nadu, this soil is very useful for growing tea and coffee. Red laterite soils in Tamil Nadu, Andhra Pradesh and Kerala are more suitable for crops like cashew nut.

Arid Soil

Features of Arid Soils

• They range from red to brown in colours.
• They are generally sandy in texture and saline in nature.
• In some area salt content is so high that common salt is obtained by evaporating the water.
• Due to dry climate, high temperature evaporation is faster and the soil lacks humus & moisture.

• In lower regions soil has Kankar in it because of the increasing calcium content.
• It restricts the infiltration of water.
• After proper irrigation these soil become cultivable, as it is done in western Rajasthan.

Forest Soil

Features of Forest Soil

• These soils are found in the hilly areas with rain forests.
• Soil texture varies according to the mountain environment.
• They are loamy & silty in valley sides.
• They are coarse grained in the upper slopes.
• In the snow covered areas of Himalayas, they experience denudation and are acidic with low humus content.

• The soils are formed in the lower parts of the valley on the river terraces and alluvial fans are fertile.

Soil Erosion

The denudation of soil cover and subsequent washing down is described as soil erosion.

Causes of Soil Erosion:

• Human activities like deforestation, over-grazing, construction and mining.
• Defective methods of farming.
• Ploughing in a wrong like up and down the slope forms channels makes way for quick flow of water. This leads to soil erosion. way etc. disturb this balance. Natural forces like wind, glacier and water lead to soil erosion.
• Sometimes water flows as a sheet over large areas down a slope. In such cases the top soil is washed away. This is known as sheet erosion.
• Wind blows loose soil off flat or sloping land known as wind erosion.

Effects:

• Makes land unsuitable for cultivation.
• Land so developed is called bad lands, in the Chambal basin they are known as ravines.

Various types of Soil Erosion:

Gullies: The running water cuts through the clayey soils and makes deep channels called gullies.

• Bad Lands: When the land becomes unfit for cultivation, it is called Bad Lands. Eg. ravires in Chambal
• Sheet Erosion: Sometimes water flows as a sheet over large areas down a slope. In such cases the top soil is washed away. It is called sheet erosion.
• Wind Erosion: wind blows loose soil off flat or sloping land is called wind erosion.

Soil Conservation

• Contour Ploughing: Ploughing along the contour lines can decelerate the flow of water down the slopes.
• Terrace Farming: Steps can be cut out on the slopes making terraces to restrict erosion. Western and central Himalayas have well developed terrace farming.
• Strip Cropping: Large fields can be divided into strips. Strips of grass are left to grow between the crops. This breaks up the force of the wind.
• Shelter Belts: Planting lines of trees to create shelter also works in a similar way. Rows of such These shelter belts have contributed significantly to the stabilization of sand dunes and in stabilizing the desert in western India.

Frequently Asked Question (FAQs)

Q1. What is black soil used for?

Ans. This soil is used for rice, wheat, sugarcane, and cotton. It is also used to produce nuts, sorghum, and oilseeds. Black soil is suitable for growing cotton, sugarcane, tobacco, wheat, sorghum, and oil seeds. Black soil is the best type of soil for the cultivation of cotton.

Q2. Where do we get black soil?

Ans. This soil is found mainly in Maharashtra, Madhya Pradesh, parts of Karnataka, Andhra Pradesh, Gujarat, and Tamil Naidu.

Q3. What are the characteristics of black soil?

Ans. Black soil is made up of extremely high materials, i.e., clayey. They are well-known for their moisture-retaining properties. Generally, they are rich in soil nutrients, such as calcium carbonate, magnesium, potash, lime, etc.

Q4. Are black soil acidic or alkaline?

Ans. The soil is rich in clay particles (montmorillonite) and is neutral to slightly alkaline. The soil is rich in foundations, lime, and calcium. The pH of black soil is 7.2 - 8.5. The soil has no nitrogen, phosphate, or organic matter but is rich in potash, calcium, and magnesium.

Q5. What is the main drawback of black soil?

Ans. The main drawback of black soil is:

1. It does not contain phosphorus.
2. They stick when wet because they are very difficult to work with.