Tick the most suitable answer in questions 1 and 2.
Question1. In addition to the rock particles, the soil contains
(i) air and water
(ii) water and plants
(iii) minerals, organic matter, air and water
(iv) water, air and plants
Solution 1. (iii) minerals, organic matter, air and water.
Question 2. The water holding capacity is the highest in
(i) sandy soil
(ii) clayey soil
(iii) loamy soil
(iv) mixture of sand and loam
Solution 2. (ii) clayey soil
Question 3. Match the items in Column I with those in Column II:
| Column I | Column II |
| (i) A home for living organisms | (a) Large particles |
| (ii) Upper layer of the soil | (b) All kinds of soil |
| (iii) Sandy soil | (c) Dark in colour |
| (iv) Middle layer of the soil | (d) Small particles and packed tight |
| (v) Clayey soil | (e) Lesser amount of humus |
Solution 3.
| Column I | Column II |
| (i) A home for living organisms | (b) All kinds of soil |
| (ii) Upper layer of the soil | (c) Dark in colour |
| (iii) Sandy soil | (a) Large particles |
| (iv) Middle layer of the soil | (e) Lesser amount of humus |
| (v) Clayey soil | (d) Small particles and packed tight |
Question 4. Explain how soil is formed.
Solution 4. Due to rock weathering soil is formed. The process of physical breakdown and chemical decomposition of minerals by wind, water and climatic changes is known as weathering. Rocks are converted to small pieces, which then turn to soil particles to form a layer of soil by the process of weathering.
Question 5. How is clayey soil useful for crops?
Solution 5. Clayey soil is useful for crops in the following manner:
- Its water-holding capacity is excellent.
- It is rich in organic matter.
- for growing cereals like wheat clayey and loamy soils are useful.
- The water-holding capacity of clayey soil helps in the growth of crops which require more water to grow like paddy.
Question 6. List the differences between clayey soil and sandy soil.
Solution 6.
| Clayey Soil | Sandy Soil |
| 1. Particles of clayey are finer. | Particles of sand are larger. |
| 2 clayey soil has tightly packed particles. | Sandy soil has loosely packed particles. |
| 3. water holding capacity is high. | Water holding capacity is low. |
| 4. It is heavy-weight soil. | It is lightweight soil. |
| 5. clayey soil is rich in humus and organic nutrients. | Sandy soil is not rich in humus and organic nutrients. |
| 6. this soil has little amount of air between the particles. | This soil has more air between the particles. |
Question 7. Sketch the cross-section of soil and label the various layers.
Solution 7.
Question 8. Razia conducted an experiment in the field related to the rate of percolation. She observed that it took 40 min for 200 mL of water to percolate through the soil sample. Calculate the rate of percolation.
Solution 8.
Amount of water = 200 ml
Percolation time = 40 minutes
Percolation rate = Amount of water / Percolation time
= 200/40
= 5ml/min
Question 9. Explain how soil pollution and soil erosion could be prevented
Solution 9. Soil pollution can be prevented in the following ways:
- Plastic is a big threat to soil quality so we can reduce soil pollution by reducing the use of plastics.
- We can also control this by controlling the use of chemical fertilisers and pesticides.
Soil erosion can be prevented in the following ways:
- By planting more and more trees.
- By controlling deforestation and avoiding overgrazing of animals.