SOIL NOTES

Tick the most suitable answer in questions 1 and 2

1. In addition to the rock particles, the soil contains
(i) air and water
(ii) water and plants
(iii) minerals, organic matter, air and water
(iv) water, air and plants
2. The water holding capacity is the highest in
(i) sandy soil
(ii) clayey soil
(iii) loamy soil
(iv) the mixture of sand and loam
3. Match the items in Column I with those in Column II:
Column I                                                             Column II

(i) A home for living organisms              (a) Large particles

(ii) The upper layer of the soil                (b) All kinds of soil

(iii) Sandy soil                                             (c) Dark in colour

(iv) The middle layer of the soil              (d) Small particles and packed tight

(v) Clayey soil                                              (e) A lesser amount of humus

4. Explain how soil is formed.
Soil is formed by the process called Weathering. Weathering is the breakdown of rocks
by the action of wind, water, and climate.
5. How is clayey soil useful for crops?

● It has very good water holding capacity.
● It has little air.
● y sticky when wet.
6. List the differences between clayey soil and sandy soil.

Clayey Soil Loamy Soil

(i) clay particles are very small. (i) Loamy particles are very large.

(ii) It has very good water holding capacity. (ii) It has the right water holding capacity.

.

(iii) It’s very sticky. (iii) It is loose and looks rich

(iv)It is reddish-brown in colour (iv)It is dark brown in colour.

(v) It has little air (v) It has adequate air space.

(vi)Fertile (vi)Not fertile.

7. Sketch the cross-section of soil and label the various layers.   

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 the soil sample. Calculate the rate of percolation.
Given amount of water=200ml
Percolation time =40 min
Therefore, Percolation rate =Amount of water(ml)
                                                     Percolation time(min)

                                                   =200ml
                                                      40min
                                                   = 5ml/min

9. Explain how soil pollution and soil erosion could be prevented.
soil pollution can be done by
(i) use of manure instead of synthetic fertilisers
(ii) industrial waste should be treated before releasing in soil
(iii) avoid dumping of polythene and plastics in soil
Prevention of soil erosion can be done by
(i) afforestation that is large scale planting in place of cut down forests.
(ii) avoiding overgrazing of grasslands.
(iii) terrace farming and other better farming methods in hilly
areas.
10. Solve the following crossword puzzle with the clues given:

 

Across 2. Plantation prevents it. 5. Use should be banned to avoid soil pollution. 6. Type of soil used for making pottery. 7. Living organism in the soil. Down 1. In the desert, soil erosion occurs through. 3. Clay and loam are suitable for cereals like. 4. This type of soil can hold very little water. 5. The collective name for layers of soil.

Answer: Across

2.Erosion 5. Polythene 6.  Clay 7.  Earthworm Down: 1. Wind 3. Wheat 4. Sandy 5. Profile