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NIOS Silver Jubilee Year

Study Of Soil

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This OER will enable you to

  • Do the ‘soil testing’ and treat the soil based on the test results.
  • Identify the type of his/her soil and decide to select the crop/s accordingly.

Study of Soil

Basically, soil is made up of different components. Following figure gives an idea of components of soil.
Factors which contribute in the formation of soil are:

Major soil types found in India

Following are the types of soil according to the Topography/ climatic conditions of soil are:

1. Red Soil:

This type of soil is suitable for rice, millets, tobacco and vegetables (also groundnuts and potatoes at higher elevations).

2. Laterites and Lateritic soil:

These soil are rich in iron and aluminium. They are formed by intensive and long-lasting weathering (Laterization**) of underlying parent rock.
It is suitable for tea, coffee, rubber, cinchona, coconut and suitable for rice and millet cultivation if manure are added. (** Laterization is a prolonged process of chemical weathering which produces a wide variety in the thickness, grade, chemistry and ore mineralogy of the resulting soils)

3. Black soil:

These soils are ideal for cotton crop, for growing cereals, oilseeds, citrus fruits and vegetables, tobacco and sugarcane.

4. Alluvial soils:

These soils occur along rivers and represent the soil materials that have been deposited by the rivers when are in flood. Their chemical composition makes them one of the most fertile soils in the world.

5. Desert soils:


6. Forest and hill soils:

These serve a very useful purpose by supplying forest product such as timber and fuel. Forest and hill soils are good for plantation of tea, coffee, spices and tropical fruits.

7. Saline and Alkaline soils:

These are poor in drainage and are infertile. The accumulation of salts makes the soil infertile and renders it unfit for agriculture.

8. Peaty and Marshy soils:

When properly drained and fertilized, these soils produce good crops of rice.


  • Try to find out the ‘soil type’ in your area.
  • Make a list of crops which you can take according to the soil type.


Match the following:


Jammu & Kashmir


Black soil

Red soil

Forest & mountains

Characteristics of an ideal soil with respect to plant growth

• The soil should be well aerated: Plant roots breath oxygen from the aerated soil. Also, if oxygen is present in the soil, micro-organisms will grow there which eventually are helpful for crop growth.
• pH of the soil should be between 6 to 8: pH of the soil should be between 6 to 8 for proper crop growth This is because, in this pH, nutrient movement will be good. Please click the following link for more information on ‘pH of soil’:

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• It should have good water holding capacity.
• It should also have well drainage capability for excess water.
• Soil should have good amount of organic matter and available nutrients.
• It should be free from soil borne diseases and pests.
• Soil should be deep, friable and well textured.
Activity no. 3
We all know that any plant can not grow in the sand. Why? Do the following activity to know the answer.
1. Take 2 disposable cups of normal size.
2. Make 1 or 2 small holes at the bottom of the cups.
3. In one cup, take 50 gms of completely dried soil from your field and take 50 gms of sand in another cup.
4. Add 5ml water in both the cups.
5. Water will be washed off from the ‘sand filled cup’.
6. Continue adding 5 ml water in the ‘soil filled cup’ until it starts coming out from the cup.
7. Note down how much water got absorbed in the soil. This is called ‘Field capacity of soil’. It is directly related to the ‘Water holding capacity’. Now, you know that sand doesn’t absorb much water and that is why water as well as other nutrients gets washed off from the sand. So plant can not grow in the sand.

Necessary nutrients for plant growth

Plants need 16 essential nutrients for healthy growth and development. Most of these nutrients are provided by soil.
Main nutrients:
Nitrogen (N), Phosphorus (P), Potassium(K)
Secondary nutrients:
Calcium (Ca), Magnesium (Mg), Sulphur (S)
Micro nutrients:
Iron (I), boron (B), zinc (Zn), copper (Cu), molybdenum (Mo), chlorine (Cl), manganese (Mn)
Nutrients from air:
Carbon (C), hydrogen (H)
Nutrients from water:
Oxygen (O)
Apart from above nutrients, there are some other parameters which also affect plant growth. These parameters are: Soil pH, Soil EC (Electrical Conductivity) and Soil OC (Organic Carbon). To judge the health of soil, these parameters should be checked.

Why do we need soil testing?

Soil supplies many necessary nutrients required for healthy growth of a crop. The yield is largely dependent on the soil in which the crop grows. So, before cultivation, it is very important to check the soil for its nutrients. By soil testing you will know whether the soil is having enough amount of nutrients or not. If any nutrient is less or more than the required amount, necessary measures can be taken.

Benefits of soil testing

Soil testing encourages plant growth by providing the best fertilizer recommendations.

  • It diagnoses whether there is too little or too much of a nutrient. 
  • Soil testing promotes environmental quality.
  • It also saves money that might otherwise be spent on unneeded fertilizer.

Please click the following link for more information on ‘Soil Testing’,

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Various types of ‘Soil Testing Kits’ are available in the market. You can go for any of those. We are using a readymade kit from ‘Prerana Lab’ for our tests. Steps of the tests are given by assuming that you have a kit from ‘Prerana Lab’.
For detail information about ‘Soil Testing’, please click on the following link:

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Soil supplies all the important factors for the growth of crop plants.
The type and properties of soil directly affect the crop growth and yield, hence management and conservation of soil is important.
Ideal soil for crop production should be well aerated, have good water holding capacity, and optimum pH.
The quality of soil can be improved by proper techniques cropping pattern.
Soil testing is very important to select the crop and do the soil treatment accordingly.

Inkpot.png Assignments

1. Collect soil sample from your farm and record your observations like soil color, soil structure as sandy /loamy etc.
2. By following the steps given in the ‘Soil Testing’ presentation, collect the soil samples from your area and do the necessary testing.
3. Select the crop by considering the tests results along with other things like soil properties, type etc.