What are Inorganic Materials?

Inorganic materials are those materials which are not living, include minerals and whethered rocks

What is Pedology?

Pedology deals with pedogenesis, soil morphology and soil classification.

In simpler words, pedology studies the origin of the soil,the classification of soils and description of the soils.

What is Edaphology?

Edaphology studies the way the soils influence plants, fungi and other living organisms.

What are the Classifications of Soils?

The soil,in fact is different in each area of the world has its own climate,rocks and vegetation and therefore,its own soils, with unique characteristics.

So the Classification of Soils have been evolved by a number of systems for categorizing various types of soils.

Urvara and Usara – Classification of Soil based on Ancient Period

Soil existed on the earth’s surface since the beginning and thus the classification was done on the basis of whether the soil is fertile or not.

The classification were

• Urvara
• Usara

What is the difference between Urvara and Usara soil?

Urvara is a fertile type of soil and Usara is a infertile type of soil.

What are Sterile Soil?

Usara is also called “Sterile soil” which means infertile.

Even though, the classification of ancient type of soils are not in as detail as the modern classification of soils.

How Soils are classified based on the Texture?

The classification is based on the basis of particle sizes and composition of soil.

These are “sand”,”slit”,”clay” and then there is a fourth texture called “loam”.

What are the modern Classification of Soils in India?

When human beings started to know about the various characteristics of soil, they began to classify the soils on the basis of slope,texture,color,moisture etc.

Several Agencies were involved for classifying the soils in the modern period.

1. Soil Survey Of India (SSI)
2. National Bureau of Soil Survey and the land use planning (NBSS & LUP)

The Soil survey of India was established in 1956.The soil survey of India studied soils of India and their characteristics.

National Bureau of Soil Survey and the Land Use Planning is an institute under the control of Indian council of Agriculture Research (ICAR) did a lot of studies on Indian Soil.

Classification of Soils in India on the basis of ICAR are

• Alluvial soil
• Red Soil
• Black Soil
• Arid Soil
• Laterite Soil
• Saline Soil
• Peaty/Marshy Soil
• Forest and Mountain Soil
• Snowfields

Soil Formation in India

The formation of soil is a long process that is continued over thousands of year.The weathering of rocks and minerals initiates the formation of soil.The rocks on the surface breaks down into smaller pieces through the process of weathering and is mixed with organic matter and over time this forms a thin layer of soil.

                                  Formation of soils by weathering of rocks

Plants attract animals and when animals die, their bodies decompose.This decomposition makes the soil rich and thick.

But there are a number of factors responsible for soil formation in India.So lets go through one by one.

What are the factors responsible for the formation of Soil in India?

Factors Responsible for soil formation in India

1. Parent Material
2. Relief or Slope
3. Climate
4. Natural Vegetation.

Parent Material

As the name suggests, the soil formed is derived from the rocks of its parent.The parent material are termed by soil scientists.

The parent material helps in determining the

• soil color
• minerals in the soil
• texture of the soil i.e,whether the soil is clayey,loamy,sandy or silty

In India,parent material are categorized into six classes:

1. Ancient crystalline and Metamorphic rocks.
2. Cuddapah and Vindhyan rocks
3. Gondwana rocks
4. Deccan basalts
5. Tertiary and Mesozoic sedimentary rocks of extra peninsular India
6. Recent and sub-recent rocks

Relief or Slope

Relief influences the formation of soil in many ways.But the most important being the slope of the land.

For example , chambal ravines that flows between Rajasthan and Madhya Pradesh which contains a steep slope making the flow of rivers to flow faster, which results in the hindrance of soil formation and there is a chance of occurrence of soil erosion.Thus steep slope causes soil erosion.

On the other hand,gentle slope or low relief also largely determines the fertility of the soil.You can set the alluvial soils as an example, as it contains thick layers, which makes the alluvial soil deep and this results increase in the fertility of the soil.

Hence,relief or slope role be important in the formation of soils in India.

Climate

Climate is the most important factor of all the factors of formation of soil in India,due to the following reasons.

Rainfall and temperature

Amount of rainfall and temperature for a soil formation is largely contributed by the climate.

Micro organisms

The presence of micro-organisms is directly controlled by the climatic conditions of a region.

Rainy season

If the climate is rainy,the upper soil is degraded as a result in the occurrence of soil erosion.

Desert Region

In arid and semi-arid regions (desert regions), evaporation always exceeds precipitation.This results in very little vegetation and the soils badly lacks in humus content.

Himalayan region

In cold climates of Himalayan region, the process of plant decay is very low, which makes the formation of soil to grow acidic in nature.

Thus these are the major reasons to prove that climate plays a very crucial role in the formation of soil.

Natural vegetation

Natural Vegetation is formed by the combined effects of climate and relief. The soil formed has a great impact from the growth of vegetation because the remains of plants which are decayed over a large duration adds much humus which helps to increase the fertility of the soil.As a result,the forest regions of the country contain the best soils in India.

Hence, natural vegetation plays a very crucial role in the formation of soils in India.

So now lets find out on the basis of above factors discussed how different types of Soils in India are formed.

How Soils in India are formed?

How Alluvial Soil is formed?

Alluvial soil is formed by the deposition and transportation of silts and sediments bought down by the rivers while flowing through the mountains.

In geology,something made up of or found in the materials that are left by the water of rivers, floods etc.Hence, these soils are named as alluvial soils.

How Black Soil is formed?

Formed due to solidification of lava spread over large areas during volcanic activity in the Deccan plateau thousands of years ago.

How Red Soil is formed?

Formed due to decomposition of ancient crystalline rocks like granites and gneiss and from rock types rich in minerals such as iron and magnesium. The term “red soil” is due to wide diffusion of iron oxides through the materials of the soils.

How Laterite Soil is formed?

The alteration of wet and dry season leads to the leaching away of siliceous matter and lime of the rocks and the soil rich in oxides of iron and aluminum compounds is left behind.

How Peaty and Marshy soils are formed?

Originate in the humid regions  as a result of accumulation of large amounts of organic matter in the soil. They contain considerable amounts of soluble salts and 10-40% of organic matter.

How Desert Soils are formed?

Desert soil form in arid climates , where evaporation is five times more than annual precipitation from rain and snow.

How saline and Alkaline soils formed?

Some of the salts are transported in solution by rivers and canals , which percolates in the sub- soils in the plains.

How Forest and Mountain soil is formed?

Soil type of mountains are mainly found in hill slopes are mainly formed by deposition of organic matter from woodlands and forests. Mountain soils are generally located in the dry and cold districts like Ladakh, Lahaul and Spiti District , Kinnaur District etc.

What are the Crops grown by Different Soils in India ?

Crops grown by Different Soils in India

Rice

• Rice is the staple food of people living in eastern and southern parts of the country.
• It requires hot and humid conditions for growing with 24 C mean temperature at 150-300 cm rainfall.
• Rice can be grown on a variety of soils including slits, loams, gravels and can tolerate acidic as well as alkaline soils.
• This type of crop requires sufficient water to grow well.Therefore, the soil used in growing rice should have a good water holding capacity.
• Silt clay,silt clay loam and clay are some of the soil textures that are best for rice farming.
• The pH of Soil should be 5 to 8.
• Flat lands are better for rice farming.

So, it grows well in Alluvial,Red,Black soil.

Wheat

• Wheat is the 2nd most food crop of India.
• Wheat needs 12 to 15 inches of water to produce a good crop.
• It grows best when temperatures are warm, from 21 to 24C,but not too hot.
• Wheat also needs a lot of sunshine,especially when the grains are filling.
• Plain land or gentle slope is ideal for wheat cultivation.
• It is a crop which is grown in winter.
• U.P is the largest producer of wheat followed by Rajasthan,Haryana
• pH of wheat is 6.0 – 6.8
• acidic
• type of loamy,clay

So, wheat grows well in black soil.

Maize

• Maize is popularly known as corn worldwide.
• Maize is known as queen of cereals because it has highest genetic yield potential among the cereals
• In India maize or corn is the third most important food cash crops after wheat & rice.
• Maize is grown throughout the year in all states of the country.
• Maize is largely cultivated crop in north India.
• Major maize or corn growing states are Mp followed by u.p , Rajasthan, Bihar and Karnataka and Andhra Pradesh states are the major producers of maize in south India.
• Local names of Maize in India : Maka (Hindi, Marathi, Oriya),Bhutta (Bengali), Makai (Gujarati), Makka’y (Kashmiri), Musikinu jola (Kannada), chollam (Malayalam), makai chollam (Tamil Nadu), Mokka Jonalu (Andhra Pradesh)
• Maize is a rain-fed kharif crop which is sown just before the monsoon starts.
• Maize grown well under temperatures varying from 22c to 30c, but can tolerate upto 35c
• Maize requires 50cm to 90cm of rainfall.
• Maize can be successfully cultivated in a variety of soils ranging from clay loam to sandy loams to black cotton soil.
• For better yield of maize,one should consider soils with good organic matter content having high water holding capacity. With drained soils with pH of 5.5 to 7.0 are preferred for maize farming,
• Soil test is recommended to find out deficiency of any nutrient values in the soil, any deficiency can be covered by adding good organic matter or compost at the time of land preparation.

Cotton

• Cotton is the most important fiber crop not only in India but of the entire world.
• Cotton is a water thirsty crop and 6% of the water for irrigation in India is used for cotton cultivation.
• It provides basic raw material for cotton textile industry.
• Gujarat, Maharashtra, Punjab, Uttar Pradesh, Madhya Pradesh, TN, AP are the principle cotton producing states in India.
• Types of Cotton:

1. Long Staple Cotton – length varies from 24 to 27mm
2. Medium Staple Cotton – length varies from 20 to 24mm
3. Small Staple Cotton – length varies from less than 20mm long

• Hot and moist climate is ideal for cotton farming.
• Seventy percent cotton is rain-fed. Clear Sunshine and proper moisture level during boll information is required.
• Temperature – 25c is ideal for cotton cultivation.
• Rainfall – 150cm to 200cm rainfall is essential for cotton farming.Moisture in the wind is necessary.
• Soil – Irrigated cotton should be grown on medium black to black deep soil having pH range between 6 to 8.
• Saline soil is not suitable for cotton cultivation.
• Soil should have proper drainage.
• The depth of the soil should be less than 20 to 25cm.
• Frost is effected by cotton crop.

Millet

• Millet have been cultivated in India since pre-historic times.
• Millet’s are generally grown as mixed crops in regions of low rainfall, the other crop grown with them being one of the legumes.
• Most of the millets grown in our country are of short duration, taking, three to four months from sowing to harvesting. Some of the indian are Sorghum, pearl ,millet and finger millet.
• India is one of the leading countries in the world the production of sorghum. The area under this millet is 42.6 million acres,and the production of the grain is estimated lit about 7.4 million tonnes.
• It is chiefly cultivated in Uttar Pradesh, Punjab, Madhya Pradesh, Chhattisgarh, Andhra Pradesh, Maharashtra and Rajasthan.
• The plants are  tall coarse annuals, growing to a height of from 90cm to 4.5 in, in nil- florescence is a dense head or panicle.
• The grains are small, white, pinkish in color.
• They can be easily grown in less irrigated and arid regions.

Sugarcane

• Sugarcane is one of the main cash crops of India.
• From its juice sugar,gur,alcohol etc. are produced. After the extraction of the juice the fibrous mass left behind is used for making paper and sound insulating board.
• Sugar is a troical crop cannot be cultivated in cold regions.
• It requires rainfall of 150cm and temperatures between 20 to 26c.
• Sea breeze – It grows best when the salt breeze from the sea blows over it.
• Soil – Deep slits or fertile loamy soils rich in lime and salts are very suitable.
• Relief – Stagnant water is harmful for sugarcane cultivation.So well drained level land or sloping is suitable.
• India  ranks second in the world in sugarcane production. Tn ranks first in India in highest yield per hectare, followed by Karnataka.

Tobacco

• India is the 2nd largest producer of tobacco with 800 million kg.
• Tobacco occupies a meager 0.24% of the country’s total arable land area.
• It is largely grown in semi-arid and rain-fed areas where the cultivation of alternative crops is economically unviable.

Potato

• Potato will grow in any well-drained soil, but they dislike soggy soil.
• Because they do all the growing underground, they can expand more easily in loose, loamy soil than in heavy, compacted, clay soil that keeps plants roots from getting the air and water they need.
• The maximum and minimum temperatures are from 30 to 32 and 18 to 20 c respectively.
• Crop rotation is very important in potato farming.
• Drip irrigation helps farmers increasing potato yield.
• Potatoes are slightly acid soil, pH is around 5.0 but will grow in a range from 5.0 to 6.5.
• Common potato scab can be a problem if the soil pH levels are of sweet or alkaline side.

 Tea

• Tea is the most important beverage of India.
• Tea thrive well in hot and humid climate .
• There is a very close relation between climate, the yield and the quality of tea. The ideal temperature for its growth is 20 to 30c  and the temperatures above 35 and below 10c are harmful for the bush.
• It requires 150 -300 cm annual rainfall which should be well distributed throughout the country.
• Tea bush grows well in well drained, deep , friable loams.
• However, virgin forest soils rich in humus and iron content are considered to be the best soils for tea plantations.

Coffee

• Coffee is the second most important beverage crop of India.
• Coffee requires hot and humid climate with temperature varying between 15 to 28c and rainfall from  150 to 250cm.
• Dry weather is necessary at the time of ripening of the berries.
• Well drained,rich friable loams  containing good deal of humus and minerals like iron and calcium are ideal for coffee cultivation.

What is the importance of pH in Soil?

Soil pH affects the soil’s physical,chemical and biological properties and processes, as well as plant growth. the nutrition,growth, and yields of most crops decrease where pH is low and increase as pH rises to an optimum level.

What is pH?

pH is defined as the negative logarithm (base 10) of the activity of hydronium ions (H+) in a solution.

pH value of crops in India

Rice – 6.0 to 6.7

Wheat – 6.0 to 6.8

Maize – 5.5 to 7.0

Cotton – 5.8 to 8.0

Millet –  5.0 to 5.5

Sugarcane – 5 to 8.5

Tobacco – 6.2 to 7.5

Potato – 6.1 (approximately)

Tea – 4.0 to 6.0

Coffee – 5.0

pH value of soils in India

In general, most of the soils in India are most acidic to neutral in nature.

Alluvial Soil pH value is 6.5 to 8.4

Black Soil pH value is 6.5 to 8.4

Red Soil pH value is 5.5 to 7.5

Laterite Soil pH value is 4.5 to 6.5

Forest Soil pH value is 6.0 to 7.0

Mountain soil pH value is 5.0 to 6.5

Arid and Semi Arid Region pH value is 7.6 to 8.4

Peaty or Marshy soil pH value is 4.4 (approximately)

Saline and Alkaline soil pH value is close to 8.5

What is meant by soil acidity?

Soil Acidity is defined as any soil that has a pH of lesser than (

What is meant by Soil neutrality?

Soil neutrality is defined as any soil that has a pH value equal to 7.0

What is meant by soil alkalinity?

Soil Alkalinity is defined as any soil that has a pH of greater than (>) 7.0(neutral value of pH).Alkalinity is due to OH- ion concentrations of the soil.

Generally, the pH value of Alkaline soil is more than 8.5 due to the presence of sodium carbonate in the soil, as when water combines with sodium carbonate, the OH- ions are formed.

Alkaline soils has a poor soil structure  and a low infiltration capacity.The presence of sodium carbonate, causes the soil to swell and difficult to clarify/settle.Thus, they are not suitable for agricultural purposes.

If the taste is sweet, then the soil is alkaline in nature.

Usar soils are alkaline in nature.