Science

Soil

Question:

Explain how soil pollution and soil erosion could be prevented.

Answer:

Prevention of soil pollution:
The persistent build-up of toxic compounds in the soil is defined as soil pollution. To prevent soil pollution, its causes must be controlled.

  1. Reduce the use of plastics: Plastics and polythene bags destroy the fertility of soil. Hence, these should be disposed off properly and if possible, their use should be avoided.
  2. Industrial pollutants: Some waste products from industries and homes pollute soil. These pollutants should be treated chemically to make them harmless before they are disposed off.
  3. Insecticides: Other pollutants of soil include pesticides and insecticides. Therefore, excessive use of these substances should be avoided.

Prevention of soil erosion:
Removal of the upper fertile layer of the soil (top soil) by strong wind and flowing water is known as soil erosion. Following steps can be taken to reduce soil erosion:

  1. Mass awareness to reduce deforestation for industrial purposes.
  2. Helping local people to regenerate degrading forest.
  3. Planting trees.
previuos
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Soil

Q 1.

Explain how soil pollution and soil erosion could be prevented.

Q 2.

Tick the most suitable answer in question 1 and 2.
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

Q 3.

List the differences between clayey soil and sandy soil.

Q 4.

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

Q 5.

The water holding capacity is the highest in
(i) Sandy soil
(ii) Clayey soil
(iii) Loamy soil
(iv) Mixture of sand and loam

Q 6.

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.

Q 7.

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

Q 8.

How is clayey soil useful for crops?

Q 9.

Explain how soil pollution and soil erosion could be prevented.

Q 10.

Explain how soil is formed.

Q 11.

Solve the following crossword puzzle with the clues given:
ncert-solutions-class-7-science-chapter-9-soil-3
Across
2. Plantation prevents it.
5. Use should be banned to avoid soil pollution.
6. Type of soil used for making pottery.
7. Living organism in the soil.

Down
1. In desert soil erosion occurs through.
3. Clay and loam are suitable for cereals like.
4. This type of soil can hold very little water.
5. Collective name for layers of soil.