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Q1. (i) Why potato grows well in sandy soil? (ii) Does planting trees affect soil erosion? How?

Solution

(i) Because potato needs proper soil air and soil rich in plant nutrients so it can grow in less water.(ii) Yes, planting trees helps in reducing the soil erosion as the roots of the plants bind the soil particles together and thus, they hold soil particles and prevent soil erosion.

Q2. Which constituent of mountain soil makes it fertile?

Solution

Mountain soil is made up of sand, stones, clay limestone. It has the highest content of humus of all the soil types. This makes mountain soil very fertile.

Q3. List any two properties of healthy soil.

Solution

The two characteristics of healthy soil are: a. It is a mixture of different sized particles. b. It is rich in humus.

Q4. Why wheat and rice are majorly grown in Punjab?

Solution

In Punjab, five rivers flow which brings alluvial soil with them. Alluvial soil is the most fertile soil which is suitable for the growth of wheat and rice.

Q5. (i) Which B - horizon has highest mineral content and why?(ii) How soil is important for plant growth?

Solution

(i) B- horizon has highest mineral content because when rainwater seeps through the topsoil, it dissolves minerals and deposits them in this layer.(ii) Soil is necessary for plant growth because a.It provides mechanical support to plants. b.It provides water and nutrients to the plants.

Q6. How humus prevents soil erosion?

Solution

Humus helps the soil to absorb surface water quickly and retain it. Thus, the soil remains wet and prevents soil erosion.

Q7. The percentage of water present in the given soil sample can be calculated by the formula

• 1)
• 2)
• 3)
• 4)

Solution

Q8. How is soil formed?

Solution

Soil is formed by breaking down of rocks by the action of wind, water and climate. The bigger pieces of rocks get converted into small pieces of soil.

Q9. Why clay is not suitable for growing plants?

Solution

Clay has smallest sized particles(less than 0.002 mm) thus it has very less soil air due to small intermolecular spaces. Its water absorbing and retaining capacity is very high thus it becomes waterlogged.

Q10. What are the properties of desert soil?

Solution

The properties of desert soil are: a. Soil is sandy and porous. b. It is rich in soluble salts. c. It has poor water retention capacity.

Q11. Why alluvial soil is suited for growth of wheat and rice?

Solution

Alluvial soil is rich in humus and is loamy in texture. Thus it is suitable for growth of wheat and rice.

Q12. How earthworms increase soil fertility?

Solution

Earthworms ingest soil, digest the organic matter present in it and excrete soil full of plant nutrients known as worm cast which makes soil fertile. They make burrows into the soil and thus they aerate the soil.

Q13. Why loamy soil is considered a healthy soil?

Solution

Loamy soil is considered a healthy soil because a. It is rich in humus. b. It has neutral pH. c. It is rich in minerals. d. It has good water absorbing and water retaining capacity. e. It is well aerated.

Q14. Which soil is best for growing masoor dal and why?

Solution

Loamy soil is best for growing masoor dal because it drains water easily.

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