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
The water holding capacity is the highest in
(i) Sandy soil
(ii) Clayey soil
(iii) Loamy soil
(iv) Mixture of sand and loam
Match the items in Column I with those in Column II:
(i) - (b)
(ii) - (c)
(iii) - (a)
(iv) - (e)
(v) - (d)
Explain how soil is formed.
The process of soil formation is a very long process. It initiates with the breaking down of rocks into smaller fragments with the action of running water, wind and moving glacier. These small broken rock particles accumulate over the ages to form soil. In due course, when plants grow on the soil, these shed their leaves to which decay form the topmost layer of the soil called 'humus'.
How is clayey soil useful for crops?
Clayey soil is made up of tightly packed very small particles, leaving little space for air in between. Since water can be retained in the tiny gaps between the particles of clay, it makes such kind of soil heavy as they have the ability to hold more water than the other kinds of soil. Apart from this, clayey soil is rich in organic mineral content. These characteristics of clayey soil make it useful for some kind of cereal crops, such as, wheat, gram and paddy.
List the differences between clayey soil and sandy soil.
Sketch the cross section of soil and label the various layers.
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.
Quantity of water = 200 mL
Percolation time = 40 min
Percolation rate (mL/min)
Therefore, Percolation rate = 5mL/min
Explain how soil pollution and soil erosion could be prevented.
The following are the ways to prevent soil pollution:
i. Avoiding dumping of non-biodegradable items in soil
ii. Before industrial wastes are disposed, those are treated to make them harmless.
iii. Using manure instead of chemical fertilizers
iv. Using natural pesticides
v. Reduce the use of polythene and plastic bags
The following are the ways to prevent soil erosion:
i. Planting trees in large scale
ii. Adopting better farming techniques, like crop rotation and mixed farming
iii. Terrace farming in hilly regions
iv. Prohibiting over-grazing of grasslands
v. Building embankment at river banks
Solve the following crossword puzzle with the clues given:
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.
1. In 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. Collective name for layers of soil.