Class 7 Science Question Answers - Soil

Very Short Q & A :

Q1: Name an important natural resource that supports growth of plants.

Ans : Soil.

Q2: Name major soil pollutants.

Ans : Polythene bags, plastics, waste products, chemicals and pesticides.

Q3: Waste products and chemicals should be treated before they are released into the soil. True/False.

Ans : The rotting dead matter in soil is called humus

Q4: Define humus.

Ans : True

Q5: What do you mean by soil profile?

Ans : A vertical section through different layers of the soil is called the soil profile.

Q6: What is soil?

Ans : Soil is the crust part of the earth. It is mainly the mixture of rock particles and humus.

Q7: Name the process by which soil is formed.

Ans : Weathering

Q8: Each layer of soil differs in feel (texture), colour, depth and _______________.

Ans : Chemical composition.

Q9: Loamy soil It is a mixture of

1. sand
2. soil
3. silt
4. All of the above

Ans : All of the above.

Q10: Loamy soil also contains humus, and is, therefore, considered the best for the growth of plants. True/ False

Ans : True

Q11: Name the soil with highest water absorption rate.

Ans : Sandy soil.

Q12: Name the soil having very less space between particles.

Ans : Clayey soil

Q13: Clay soils are heavy and hold more _______________.

Ans : Water

Q14: Ram has to grow wheat crop in his field, what kind of soil he will prefer?

Ans : Clayey soil

Q15: Deforestation causes

1. Rainfall
2. Water pollution
3. Soil erosion
4. None of these.

Ans : Soil erosion

Q16: Name some places with severe soil erosion.

Ans : Areas of little or no surface vegetation, such as deserts and barren lands.

Q17: Classify soil on the basis of appearance and properties of particles.

Ans : Sandy soil, Clay soil and Loamy soil

Q18: State one property of sandy soil.

Ans : Sandy soils are light, well aerated and dry.

Q19: State one property of loamy soil.

Ans : It is a mixture of sand, soil and silt. And also contain humus.

Q20: State one property of clayey soil.

Ans : It is made of a relatively high proportion of fine particles.

Q21: What is deforestation?

Ans : Clearing or Removal of forests or stands of trees.

Q22: In addition to rock particles, the soil contains

1. Air and water
2. Minerals
3. Minerals, organic matter air and water
4. Organic matter

Ans : Minerals, organic matter air and water

Q23: The water holding capacity is highest in

1. clayey soil
2. Loamy soil
3. Sandy soil
4. None of these

Ans : Clayey soil.

Q24: Name the soil horizon which contains humus.

Ans : A- Horizon

Q25: Upper layer of soil is ___________ in colour.

Ans : Dark

Q26: Middle layer of soil contains less amount of _________________.

Ans : Humus

Q27: Why is uppermost layer of soil, dark in colour?

Ans : Because it is rich in humus and minerals.

Q28: Suggest an alternative of chemical fertilizer.

Ans : Manures

Q29: Does Acid rain cause soil pollution or not?

Ans : Yes

Q30: We can prevent soil erosion by:

1. Using step farming in hill regions
2. Afforestation
3. Avoiding overgrazing of grass lands
4. All of these

Ans : All of these

Q31: Plastics and poly bags should get mixed in soil. True/False

Ans : False

Q32: Humus is important for soil fertility. True/False

Ans : True

Q33: If the amount of large and fine particles is about the same, then soil is called _____________.

Ans : Loamy

Q34: What is bedrock?

Ans : After the C- horizon, there lies bedrock which is hard and difficult to dig with a spade.

Q35: Name the layer of soil having lesser amount of humus but more of minerals.

Ans : B- horizon.

Q36: What kind of soil is used for making matkas and toys?

Ans : Clay soil

Q37: Give the formulae for percolation rate.

Ans : Percolation rate= amount of water (mL)/ Percolation time (min)