chapter 1

Alluvial Soil
1. Importance and Distribution
 Most Widely Spread Soil: Alluvial soil is the most widely spread and
important type of soil in India.
 Northern Plains: The entire northern plains are composed of alluvial soil.
 Formation: Deposited by the three Himalayan river systems – Indus, Ganga,
and Brahmaputra.
 Other Regions:
o Extends into Rajasthan and Gujarat through a narrow corridor.
o Found in the eastern coastal plains, particularly in the deltas of the
Mahanadi, Godavari, Krishna, and Kaveri rivers.
2. Composition and Characteristics
 Components: Contains various proportions of sand, silt, and clay.

 Grain Size:
o Bigger soil particles are found as we move inward towards river valleys.
o In the upper reaches of river valleys (near the break of slope), soils are
coarse.
o Coarse soils are common in the piedmont plains, such as Duars, Chos, and
Terai.
3. Classification by Age
 Old Alluvial (Bangar):

o Higher concentration of kanker nodules.
o Contains more fine particles.
o Less fertile compared to new alluvial soil.
 New Alluvial (Khadar):
o More fertile than bangar soil.
4. Fertility and Agricultural Suitability
 Fertility: Highly fertile overall.

 Nutrients: Contains adequate potash, phosphoric acid, and lime.
 Crops Grown:
o Ideal for sugarcane, paddy, wheat, and other cereal and pulse crops.
5. Special Characteristics
 Intensive Cultivation: Due to high fertility, these regions are extensively

cultivated and densely populated.
 Alkalinity in Dry Regions:
o Soils in drier regions are more alkaline.
o Can be made productive with proper treatment and irrigation.
Black Soil
1. Characteristics
 Color: Black, hence also called regur soils.

 Nickname: Known as black cotton soil due to its suitability for growing
cotton.
 Formation:
o Influenced by climatic conditions and parent rock material.
o Typical of the Deccan Trap (basalt) region formed from lava flows.
2. Distribution
 Found in the northwest Deccan Plateau.

 Covers the plateaus of:
o Maharashtra
o Saurashtra
o Malwa
o Madhya Pradesh
o Chhattisgarh
 Extends southeast along the Godavari and Krishna valleys.
3. Composition
 Made up of extremely fine, clayey material.

 Rich in soil nutrients such as:
o Calcium carbonate
o Magnesium
o Potash
o Lime
 Deficient in phosphoric content.
4. Unique Features
 Moisture Retention: Known for excellent capacity to hold moisture.

 Crack Formation:
o Develops deep cracks during hot weather, aiding in proper aeration.
 Workability:
o Becomes sticky when wet.
o Difficult to work on unless tilled immediately after the first rain or during
the pre-monsoon period.
Red and Yellow Soils
1. Formation
 Red Soil:
o Develops on crystalline igneous rocks.
o Found in areas of low rainfall, especially in the eastern and southern
parts of the Deccan Plateau.
 Yellow Soil:
o Appears yellow when it occurs in a hydrated form.
2. Distribution
 Found in:
o Odisha
o Chhattisgarh
o Southern parts of the Middle Ganga Plain
o Piedmont zone of the Western Ghats
3. Characteristics
 Color:
o Reddish due to the diffusion of iron in crystalline and metamorphic
rocks.
o Turns yellow when iron occurs in a hydrated state.
Laterite Soil
1. Origin and Formation
 Name: The word "laterite" comes from the Latin word "later", meaning brick.
 Climate: Forms in tropical and subtropical climates with both wet and dry
seasons.
 Formation: Created by heavy rain causing intense leaching (removal of
nutrients).
2. Features
 Depth: Usually deep to very deep.

 Acidity: Acidic soil (pH < 6.0).
 Nutrient Content: Often lacking in plant nutrients.
 Humus:
o Humus-rich in areas with forests (deciduous and evergreen).
o Humus-poor in areas with little vegetation and in dry regions.
3. Location
 Found mostly in:

o Southern states of India
o Western Ghats (Maharashtra)
o Odisha
o Some parts of West Bengal and North-East India
4. Soil Problems
 Erosion: Prone to erosion and damage because of where it is located on the

landscape.
5. Agricultural Use
 Tea and Coffee: After using soil conservation techniques in Karnataka,

Kerala, and Tamil Nadu, it is good for growing tea and coffee.
 Cashew Nut: Red laterite soils in Tamil Nadu, Andhra Pradesh, and
Kerala are good for growing cashew nuts.
Arid Soils
1. Features
 Color: Ranges from red to brown.

 Texture: Generally sandy.
 Salinity: Saline in nature, with high salt content in some areas. Common salt
is obtained by evaporating water.
2. Climate and Conditions
 Dry Climate: Occurs in regions with dry climate and high temperature.
 Evaporation: Faster evaporation leads to a lack of humus and moisture in the
soil.
3. Soil Composition
 Kankar: The lower layers of the soil contain kankar (a layer of calcium
carbonate), which forms due to increasing calcium content as we go deeper.
 Water Infiltration: The kankar layer prevents water from infiltrating the soil
properly.
4. Agricultural Use
 Cultivation: After proper irrigation, these soils can be used for farming, as seen
in western Rajasthan.
Forest Soils
1. Location
 Found in hilly and mountainous areas with sufficient rainfall and forests.
2. Soil Texture
 Varies based on the mountain environment:

o Loamy and silty on the valley sides.
o Coarse-grained on the upper slopes.
3. Special Conditions
 Snow-covered areas (such as the Himalayas):

o Soils are acidic and have low humus content due to denudation
(erosion).
4. Fertility
 Fertile soils are found in the lower parts of valleys, especially on:
o River terraces and alluvial fans.
Soil Erosion
1. Definition
 Soil Erosion: The denudation of the soil cover and subsequent washing
down.
2. Soil Formation and Erosion
 Simultaneous Processes: Soil formation and erosion occur at the same time
and generally there is a balance between the two.
 Disruption of Balance: This balance is disturbed due to human activities like
deforestation, over-grazing, construction, and mining, as well as natural
forces like wind, glacier, and water.
3. Types of Soil Erosion
 Water Erosion:
o Gully Formation: Running water cuts through clayey soils and makes
deep channels as gullies. The land becomes unfit for cultivation and is
known as bad land. In the Chambal basin, such lands are called
ravines.
o Sheet Erosion: Sometimes, water flows as a sheet over large areas down
a slope. In such cases, the topsoil is washed away.
 Wind Erosion: Wind blows loose soil off flat or sloping land, known as wind
erosion.
4. Farming Practices and Erosion
 Defective Farming: Ploughing in a wrong way, i.e., up and down the slope,
forms channels for the quick flow of water, leading to soil erosion.
Methods to Control Soil Erosion
1. Contour Ploughing
 Ploughing along the contour lines can decelerate the flow of water down
the slopes. This is called contour ploughing.
2. Terrace Cultivation
 Steps can be cut out on the slopes making terraces. Terrace cultivation
restricts erosion.
 Location: Western and central Himalayas have well-developed terrace
farming.
3. 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. This method is known
as strip cropping.
4. Shelter Belts
 Planting lines of trees to create shelter also works in a similar way. Rows of
such trees are called shelter belts. These shelter belts have contributed
significantly to the stabilisation of sand dunes and in stabilising the desert in
western India.

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Alluvial Soil

1. Importance and Distribution

2. Composition and Characteristics

 Components: Contains various proportions of sand, silt, and clay.

 Old Alluvial (Bangar):

4. Fertility and Agricultural Suitability

 Fertility: Highly fertile overall.

 Intensive Cultivation: Due to high fertility, these regions are extensively

 Color: Black, hence also called regur soils.

 Found in the northwest Deccan Plateau.

 Made up of extremely fine, clayey material.

 Moisture Retention: Known for excellent capacity to hold moisture.

1. Origin and Formation

 Depth: Usually deep to very deep.

 Found mostly in:

 Erosion: Prone to erosion and damage because of where it is located on the

 Tea and Coffee: After using soil conservation techniques in Karnataka,

 Color: Ranges from red to brown.

2. Climate and Conditions

 Varies based on the mountain environment:

 Snow-covered areas (such as the Himalayas):

2. Soil Formation and Erosion

3. Types of Soil Erosion

4. Farming Practices and Erosion

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