Students can Download Science Chapter 9 Soil Questions and Answers, Notes Pdf, KSEEB Solutions for Class 7 Science helps you to revise the complete Karnataka State Board Syllabus and to clear all their doubts, score well in final exams.
Karnataka State Syllabus Class 7 Science Chapter 9 Soil
Class 7 Science Soil Textbook Exercise Questions and Answers
Tick the most suitable answer in questions 1 and 2:
Question 1.
In addition to the rock particles, the soil contains:
(a) Air and water.
(b) Water and plants.
(c) Minerals, organic matter, air and water.
(d) Water, air and plants.
Answer:
(c) Minerals, organic matter, air and water.
Question 2.
The water holding capacity is the highest in:
(a) Sandy soil
(b) Clayey soil
(c) Loamy soil
(d) The mixture of sand and loam.
Answer:
(b) Clayey soil.
Question 3.
Match the items in column I with those in column II:
| Column I | Column II |
| (a) A home for living organisms (b) The upper layer of the soil (c) Sandy soil (d) The middle layer of the soil (e) Clayey soil |
(i) Large particles (ii) All kinds of soil (iii) Dark in color (iv) Small particles & packed tight (v) A lesser amount of humus |
Answer:
(a). (ii),
(b). (iii),
(c). (i),
(d). (v),
(e). (iv)
Question 4.
Explain how soil is formed.
Answer:
Soil is formed by the weathering of rocks by physical, chemical, and biological agents. It involves breaking down rocks by the physical breakdown and chemical decomposition done by wind, water, and climate. As a result, large rock pieces are converted into smaller pieces and eventually to the soil. It is a slow process.
Question 5.
How is clayey soil useful for crops?
Answer:
Clayey soil is suitable for growing wheat, gram, and paddy. Clayey soil has good water-retaining capacity. It is also rich in organic matter. These characteristics are useful for growing crops like wheat, gram, and paddy. List the differences between clayey soil and sandy soil.
Question 6.
The difference between clayey soil and sandy soil:
Answer:
The difference between clayey soil and sandy soil:
| Clayey soil | Sandy soil |
| (a) Soil consists of mainly clay particles which are very fine. (b) Water holding capacity is more. (c) Particles are tightly packed and hence it is less aerated. (d) It is heavy in weight. (e) It has the least percolation rate. (f) More fertile due to the presence of humus. |
(a) Soil consists of mainly sand particles which are comparatively bigger in size. (b) Water holding capacity is less. (c) Particles are loosely packed and hence it is more aerated. (d) It is light in weight. (e) It has a high percolation rate. (f) Less fertile due to the lack of humus. |
Question 7.
Sketch the cross-section of soil and label the various layers.
Answer:
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 tite soil sample. Calculate the rate of percolation.
Answer:
Amount of water to be percolated = 200 ml
Time taken for percolation =40 min
∴ The rate of percolation is 5ml/min.
Question 9.
Explain how soil pollution and soil erosion could be prevented,
Answer:
Prevention of soil pollution:
- Plastic and polythene bags should be disposed of properly and their use should be avoided.
- Waste products and chemicals from factories and industries should be treated before they are released into the soil.
- The use of pesticides and insecticides should be minimised.
Prevention of soil erosion:
- By planting more trees.
- By preventing deforestation and cutting of trees.
- By restricting animal overgrazing.
- By taking suitable measures to control floods.
Question 10.
Solve the following crossword puzzle with the clues given:
Across:
2. Plantation prevents it.
5. Use should be banned to avoid soil poll ut ion.
6. Type of soil used for making pottery
7. Living organisms in the soil.
Down:
1. In the desert, soil erosion occurs.
3. Clay and loam are suitable fòr cereals like.
4. This type of soil can hold very little water.
5. The collective name for layers of soil.
Answer:
