Soil is a broad term for the loose covering of earth that spreads across the planet. It is the result of the breaking up of rocks into constituent parts, which are then worked upon by a myriad of forces, including chemical interactions with salts and the physical workings of wind and water. Soil as a whole entity contains examples of three states of matter: the soil itself is solid, and both air and liquid exist in the pore spaces between individual particles of soil. There are many different types of soil on the planet, as every soil has a different composition of minerals and organics, and every soil has been subjected to different environmental constraints.FACTORS AFFECTING SOIL FORMATION

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INTRODUCTION

ClimateVegetationAge of rockRelief and Parent rock

1TYPES OF SOIL

Eight major types according to Indian Council of Agricultural Research (ICAR).

Alluvial soils

Black soils

Red soils

Laterite soils

Desert soils

Mountain soils

Saline and Alkaline soils

Peaty and Marshy soils

It is the most important type of soil found in India covering about 40 per cent of the total land area. It is very fertile and contributes the largest share of agricultural wealth. This soil supports nearly half of the Indian population.The alluvial soil is found mostly in the Northern Plains, starting from Punjab in the west to West Bengal and Assam in the east. It is also found in the deltas of the Mahanadi, Godavari, Krishna and Kaveri rivers in the Peninsular India. The northern parts and the coastal areas of Gujarat also have some deposits of alluvial soil.

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Alluvial soil

Types of soil

Alluvial soil

2TYPES OF SOIL

The new alluvium is deposited in the flood plains and deltas and are flooded

almost every year.

The old alluvium is found about 25 m above the flood level of the river valley.

The khadar soil is sandy and light in colour, while the bhangar soil is clayey and

dark.

The khadar soil is more fertile than the bangar soil.

The alluvial soils contain adequate potash, phosphoric acid and lime.

They are generally deficient in organic and nitrogenous contents.

The old alluvium often contains lime nodules, known as kankar.

The fertility of the alluvial soil varies from place to place. Due to its softness and

fertility, alluvial soil is most suited to irrigation and can produce bumper crops of

rice, wheat, maize, sugar cane, tobacco, cotton, jute, oilseeds, etc.

Many rivers originate from the Himalayan Mountains and bring a large amount of sediment with them. It is deposited in the river valleys and the flood plains. Thus, the parent material of the alluvial soils is always of transported origin.The fine particles of sand, silt and clay are called alluvium. The alluvial soil can be divided into old alluvium, also called bangar, and new alluvium, called khadar. http://www.indianetzone.com/

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Characteristics

3TYPES OF SOIL

It has been formed thousands of years ago, due to the solidification of volcanic

lava.

This soil is made up of extremely fine clayey material.

It is well-known for its capacity to hold moisture.

It is rich in calcium carbonate, magnesium carbonate, potash and lime, but

poor in phosphoric content.

During the rainy season, black soil becomes sticky and is difficult to till as the

plough gets stuck in the mud.

The black soil is locally called regur, a word derived from Telugu word ‘reguda’. It is also called the Black Cotton Soil, as cotton is the most important crop grown in this soil.

Mostly found in the Deccan Trap, covering large areas of Maharashtra, Gujarat and western Madhya Pradesh. It is also found in some parts of Godavari and Krishna river valleys, covering parts of Karnataka, Andhra Pradesh and Tamil Nadu.

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Black soil

Black soil

Characteristics

TYPES OF SOIL 4

Generally, in the upland regions, the black soil has low fertility, while in the valleys or lowlands; this soil is darker, deeper and very fertile. Due to high fertility and capacity to hold moisture, black soil is widely used for producing cotton, wheat, linseed, millets, tobacco and oilseeds. With proper irrigation facilities, this soil can also produce rice and sugar cane.

•During the hot dry season, the surface of this soil develops cracks. These cracks

help in the aeration of the soil.

•Actually the black soil should be tilled immediately after the first or the pre-

monsoon showers.

The red soil occupies about 10 per cent area of India, mostly in the south-eastern part of the Peninsular India.

The red soil is found in Tamil Nadu, parts of Karnataka, southeast Maharashtra, eastern parts of Andhra Pradesh, Madhya Pradesh, Orissa and Jharkhand.

This soil is formed due to weathering of old crystalline rocks in the areas of low rainfall. http://images.travelpod.com/tw_slides/

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Red soil

red soil

5TYPES OF SOIL

Most of the red soil has been formed due to

weathering of igneous and metamorphic

rocks.

The red colour is due to the high percentage

of iron contents.

The texture of the red soil varies from sandy

to clayey, and the majority being loamy.

On the uplands, the red soil is thin, poor, and

porous and has loose gravel.

In the lower areas, the soil is deep, rich, fine

grained and fertile.

This soil is rich in potash, but poor in lime,

phosphate, nitrogen and humus.With proper doses of fertilizers and irrigation the red soils can give excellent yields of cotton, wheat, rice, pulses, millets, tobacco, oilseeds, etc.

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Red soli at Sivanthaman , Tamil Nadu

Characteristics

6TYPES OF SOIL

The word ‘Laterite’ has been derived from a Latin word meaning ‘brick’. The Laterite soil is widely spread in India and is mainly found on the summits of the Western Ghats, Eastern Ghats, Rajmahal Hills, Vindhyas, Satpuras and Malwa plateau. It is well- developed in southern Maharashtra, and parts of Orissa, West Bengal, Karnataka, Andhra Pradesh, Kerala, Bihar, Assam and Meghalaya.

•The Laterite soil is formed under conditions of high temperature and heavy

rainfall with alternate wet and dry periods.

•Such climatic conditions promote leaching of soil. Leaching is a process in which

heavy rains wash away the fertile part of the soil.

•This soil is red in colour and composed of little clay and much gravel of red

sandstones.

•This soil, generally, is poor in lime and deficient in nitrogen. The phosphate

contents are generally high.

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Laterite Soil

Characteristics

laterite soil

7TYPES OF SOIL

Due to intensive leaching, the Laterite soil generally lacks fertility and is of low value for crop production. But when manured and timely irrigated, the soil is suitable for producing plantation crops like tea, coffee, rubber, coconut, areca nut, etc. It also provides valuable building materials.

The mountain soil is generally found on the hill slopes covered with forests. In the Himalayan region such soil is mainly found in the valley basins, the depressions and the lesser steep slopes. The north-facing slopes generally support soil cover. Apart from the Himalayan region, this soil is also found in the Western and Eastern Ghats and in some parts of the Peninsular India.

This soil is formed mainly due to the deposition of organic matter provided by

the forests.

This soil is rich in humus, but poor in potash, phosphorus and lime.

It is heterogeneous in nature and varies from place to place.

The mountain soil is sandy with gravels and is porous.

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mountain soil

Characteristics

8TYPES OF SOIL

For getting high yields of crops, heavy doses of fertilizers have to be applied. In the Himalayan region wheat, maize, barley and temperate fruits are grown on this soil. This soil is especially suitable for producing plantation crops, such as tea, coffee, spices and tropical fruits in Karnataka, Tamil Nadu and Kerala.

The desert soil is found mostly in the arid and semi-arid regions, receiving less than 50 cm of annual rainfall. Such regions are mostly found in Rajasthan and the adjoining areas of Haryana and Punjab. The Rann of Kachchh in Gujarat is an extension of this region.

The sand in the desert areas is partly of local origin and partly being blown in

from the Indus Valley.

It includes even the wind-blown loess.

The desert soil has sand (90 to 95 per cent) and clay (5 to 10 per cent).

In some regions this soil has high percentage of soluble salts, but lacks in

organic matter.

The nitrogen content is low, but the phosphate content is as high as in normal

alluvial soil.

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Desert soil

Rann of Kutchh

9TYPES OF SOIL

When water is made available through irrigation, the desert soil can produce a variety of crops, such as wheat, millets, barley, maize, pulses, cotton, etc. Shortage of water in the arid regions is the main limiting factor for agriculture.

Contains salts like Sodium, Magnesium,

Calcium.

Infertile, unfit for cultivation.

Sandy to loamy in texture.Parts of Gujarat, Rajasthan, Punjab, Haryana, U.P & Maharashtra.

Occur in Humid region.

Formed by accumulation of organic

matter.

Black in colour.

Highly acidic and heavy.Kottayam & Alleppey in Kerala, Coastal Orissa, Sundarbans of W.B

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Floating marshy peat mat at Pondicherry Wildlife Refuge

Saline and Alkaline soil

Saline and alkaline soil

Peaty and marshy soil

TYPES OF SOIL10