Soil

Q1. Fill in the blanks.

                          i.        In addition to the rock particles, the soil contains minerals, organic matter, air and water.

                         ii.        The water holding capacity is the highest in clayey soil.

                        iii.        In desert soil erosion occurs through wind.

                        iv.        Sandy soil can hold very little water.

                         v.        Soil is of different types: clayey, loamy and sandy.

                       vi.        The uppermost horizon is generally dark in colour as it is rich in humus and minerals.

Q2. True/False

                          i.        Plantation prevents soil erosion. True

                         ii.        Sandy soil is used to make pottery. False

                        iii.        Use of polythene should be banned to avoid soil pollution. True

                        iv.        Soil is important for life on the earth. True

                         v.        Each layer of soil is same in feel (texture), colour, depth and chemical composition. False

                        vi.        The loamy soil also has humus in it. True

Q3. Which type of soil is well aerated?

Ans. Sandy soil is well aerated.

Q4. Which soil has the highest percolation rate?

Ans. Sandy soil has the highest percolation rate.

Q5. Which soil has the least percolation rate?

Ans. Clayey soil has the least percolation rate.

Q6. What is humus?

Ans. The rotting dead matter in the soil is called humus.

Q7. What is soil?

Ans. The mixture of rock particles and humus is called the soil.

 
Q8. Name some soil pollutants.

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

Q9. Which soil horizon contains humus?

Ans. Topsoil or the A-horizon

Q10. Which soil horizon has a lesser amount of humus but more of minerals?

Ans. B-horizon or the middle layer

Q11. Which type of soil is the best for making pots, toys and statues?

Ans. Clayey soil is used to make pots, toys and statues.

Q12. What kind of soil should be used for making matkas and surahis?

Ans. Clayey soil should be used for making matkas and surahis.

Q13. Why the uppermost horizon is generally dark in colour?

Ans. The uppermost horizon is generally dark in colour as it is rich in humus and minerals.

Q14. What is the role of humus in the soil?

Ans. The humus makes the soil fertile and provides nutrients to growing plants.

Q15. What is soil profile?

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

Q16. What is loamy soil?

Ans. Loamy soil is a mixture of sand, clay and another type of soil particle known as silt.

Q17. What is bedrock?

Ans. Just below the C-horizon is the bedrock, which is hard and difficult to dig with a spade.

Q18. Which type of soil is best for growing wheat and gram?

Ans. Clayey and loamy soils are both suitable for growing cereals like wheat and gram.

Q19. Which areas experience more severe soil erosion?

Ans. Erosion of soil is more severe in areas of little or no surface vegetation, such as desert or bare lands.

Q20. Which type of soil is best for growing lentils?

Ans. For lentils (masoor) and other pulses, loamy soils, which drain water easily, are required.