Soil
Q21. Which type of soil is best for growing cotton?

Ans. For cotton, sandy loam or loam, which drain water easily and can hold plenty of air, are more suitable.

 
Q22. Wheat are grown in the fine clayey soils. Give reason.

Ans. Crops such as wheat are grown in the fine clayey soils, because they are rich in humus and are very fertile.

Q23. Classify the soil on the basis of the proportion of particles of various sizes.

Ans. On the basis of the proportion of particles of various sizes, the soil can be classified as sandy, clayey and loamy.

Q24. What is called soil moisture?

Ans. Soil holds water in it, which is called soil moisture. The capacity of a soil to hold water is important for various crops.

Q25. State the factors on which nature of the soil depends?

Ans. The nature of any soil depends upon the rocks from which it has been formed and the type of vegetation that grows in it.

Q26. What is silt?

Ans. Silt occurs as a deposit in river beds. The size of the silt particles is between those of sand and clay.

 
Q27. Explain how soil is formed.

Ans. The soil is formed by the breaking down of rocks by the action of wind, water and climate. It is a very slow process.

Q28. Why do air above the soil shimmer on a hot summer day?

Ans. On a hot summer day, the vapour coming out of the soil reflects the sunlight and thus, the air above the soil seems to shimmer.

Q29. Which type of soil is best for growing paddy?

Ans. For paddy, soils rich in clay and organic matter and having a good capacity to retain water are ideal.

Q30. What is weathering?

Ans. Soil is formed by the breaking down of rocks by the action of wind, water and climate. This process is called weathering.

Q31. Which type of soil retains the highest amount of water and which retains the least?

Ans. Clayey soil retains the highest amount of water and sandy soil retains the least.

Q32. Which natural resource supports the growth of plants by holding the roots firmly and supplying water and nutrients?

Ans. Soil supports the growth of plants by holding the roots firmly and supplying water and nutrients.

Q33. How is clayey soil useful for crops?

Ans. Clayey soil is useful for crops because:

                            i.        It is good at retaining water.

                           ii.        It is rich in organic matter.

Q34. What affect the soil profile and bring changes in the soil structure?

Ans. Soil is affected by wind, rainfall, temperature, light and humidity. These are some important climatic factors which affect the soil profile and bring changes in the soil structure.

Q35. Why is top soil known as the habitat of many living organisms?

Ans. Top soil is known as the habitat of many living organisms because this provides shelter for many living organisms such as worms, rodents, moles and beetles.

Q36. Why is the topsoil important for plant growth?

Ans. Top soil is important for plant growth because it is rich in humus and minerals which makes the soil fertile and provides nutrients to growing plants.

Q37. Why there is a demand to ban the polythene bags and plastics?

Ans. Polythene bags and plastics pollute the soil. They also kill the organisms living in the soil. That is why there is a demand to ban the polythene bags and plastics.

 
Q38. What are called horizons?

Ans. A vertical section through different layers of the soil is called the soil profile. Each layer differs in feel (texture), colour, depth and chemical composition. These layers are referred to as horizons.