NCERT solution for class 7 // Science // Chapter 9 - Soil

 NCERT solution > Science >Class 7 

NCERT solution for class 7 // Science // Chapter 9 -  Soil

Chapter 9 -  Soil 

Exercise .

 Tick the most suitable answer in the question 1 and 2 

Q1. In addition to the rock particles the soil contains 

i) air and water

 ii) water and plants

 iii) organic matter, air and water 

iv) water air and plants 

Q2. The water holding capacity is the highest in 

i) sandy soil

 ii) clayey soil 

iii) loamy soil 

iv) mixture of sand and loam 

Q3. Best items in column 1 with those in column 2

            Column 1                                     column 2 

1. A home for living organism.                Large particles 

2. Upper layer of the soil                         All kinds of soil 

3. Sandy soil                                              Dark in colour 

4. Middle layer of the soil                     Small particles in packed tight 

5 . Clay soil.                                             Lesser amount of humus  

Answer 

          Column 1                                     Column 2 

1. A home for living organism.                      All kinds of soil   

2. Upper layer of the soil                             Dark in colour 

3. Sandy soil                                                     Large particles 

4. Middle layer of the soil                      lesser amount of humus

5 . Clay soil.                                       small particles in packed tight 

Q4. Explain how soil is formed 

Answer- Soil is formed is formed by weathering of rocks weathering is The breakdown of rocks by the action of air water and wind soil formation is a very slow process and occurs all the time 

Q5. How is clayey soil useful for crops ?  

Answer- Clay soil is good for growing crops  cereals like  wheat gram lentils pulses because it has good water holding capacity and it is rich in humus and very fertile 

Q6. List the difference between clayey soil and sandy soil 

Answer- Clay soil 

  • In clay soil is the ratio of fine particle is higher 
  • It has good water reten capacity  
  • It is suitable for crops like paddy wheat and gram 
  • It is sticky and wet 

Sandy soil 

  • In sandy soil the ratio of soil particles are larger and higher 
  • Its loose particle so air penetrate through it 
  • It is suitable for vegetables peanuts and cotton cultivation 
  • It is dry and cannot retain water 

Q7. Sketch the cross section of soil and label the various layers 

Answer- The vertical section of soil Earth shows different layer is called soil profile and each layers shows different colour , texture and chemical composition these layers are also known as horizons 

  • The uppermost layer of the soil profile is called a horizontal it is dark in colour and rich in humus and minerals it is more fertile and provide nutrition to the growing crops it can retain more water porous and soft 
  • The next layer of the soil profile is called B horizon and it is harder than upper layer and more compactly arrange it is rich in minerals but less in humas 
  • The third layer of soil profile is called the sea horizon and is made up of small lumps of rock with cracks 
  • The the last layer of soil profile is called the horizon or bedrock it is very hard and difficult to dig 



Q8. Razia conducted an experiment in the field related to the rate of percolation she observed that it took 40 minutes for 200 ml of water to percolate through the soil sample calculate the rate of percolation.

Answer- 

Rate of percolation = Amount of water /  Percolation time  

                                = 200ml/ 40 min. = 5ml/ min 

Q9. Explain how soil pollution and soil erosion could be prevented ? 

Answer- Soil profile soil pollution and soil erosion could be prevented by following ways 

Prevention of soil erosion .

  • Planting more and more trees that we called afforestation prevent the soil erosion 
  • Avoid avoiding overgrazing in grassland areas 
  • Use the step farming in hilly regions 

Prevention of soil pollution 

  • Avoid the use of polythene and plastic they may create soil pollution 
  • Industrial waste should not release on soil surface without treating it 
  • Use manuals instead of chemical fertilizers

Q10. Solve the following Crossword Puzzle with the clues given

Across 

2. Plantation prevents it 

5. Use should be banned to avoid soil pollution 

6. Types of soil used for making pottery 

7. Living organisms in the soil .

Down 

1. In desert soil erosion occurs through 

3. Clay and loom are suitable for cereals like 

4. This type of soil can hold very little water 

5. Collective name for layers of soil .




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