Soil

Question 1

Why is soil considered a resource?

Answer 1

Soil helps in cultivation of food crops and cash crops. And hence is a resource.

Question 2

Name the components of soil and their uses.

Answer 2

• Mineral matter: Provides nutrients to plants.
• Soil Moisture: Aids absorption of minerals.
• Soil Air: Helps in respiration of roots.
• Humus: Retains moisture and enhances nutrient level.

Question 3

State the different soil texture and their advantages and disadvantages.

Answer 3

Sandy: Well aerated, poor in moisture retention. Loamy: Well aerated and good in moisture retention, none. Clay: High in moisture retention, poorly aerated.

Question 4

Why is soil profile thin on a mountain slope?

Answer 4

Soil particles tend to move downward due to gravity, resulting in a thin soil profile.

Question 5

What is soil profile? Why is erosion of top soil harmful?

Answer 5

Soil profile is the longitudinal section of soil consisting of top soil, sub soil, weathered material, and bedrock. Erosion of top soil is harmful as this layer provides most of the nutrients to plants.

Question 6

State two differences between residual and transported soils. State one example of each.

Answer 6

Residual soils resemble the underlying bedrock; transported soils resemble the rock type from where they were eroded. Residual soils are formed due to weathering; transported soils are formed due to deposition. Example: Black soil is residual; alluvium is transported.

Question 7

State three advantages of alluvial soil.

Answer 7

Alluvial soil is rich in lime and potash, annually replenished during flooding, and moisture retentive.

Question 8

Distinguish between Khadar and Bhangar.

Answer 8

New alluvium (Khadar) is more fertile; old alluvium (Bhangar) is less fertile.

Question 9

Distinguish between Alluvial Soil and Black Soil.

Answer 9

Alluvial Soil is a transported soil with clayey, loamy, or sandy texture; Black Soil is a residual soil with clayey texture.

Question 10

Distinguish between alluvial soil in Punjab and Bengal.

Answer 10

Alluvial soil in Punjab is loamy and has less moisture; alluvial soil in Bengal is clayey and has more moisture.

Question 11

Distinguish between Inland alluvium and Deltaic alluvium.

Answer 11

Inland alluvium is loamy with lower moisture retention; deltaic alluvium is clayey with higher moisture retention.

Question 12

How is the soil of Ganga delta different from Godavari delta?

Answer 12

Ganga delta soil is light brown/yellow; Godavari delta soil is black. Gangetic alluvium is finer than Godavari delta particles.

Question 13

Why is alluvial soil widely cultivated?

Answer 13

It covers the largest area, is highly fertile, and is annually replenished.

Question 14

Name two food and two cash crops grown in alluvial soil.

Answer 14

Food crops: rice and wheat. Cash crops: jute and sugarcane.

Question 15

How does the texture vary along the river valley?

Answer 15

Upper course: coarse texture. Middle course: loamy texture. Lower course near delta: clayey texture.

Question 16

Name two states with alluvial soil.

Answer 16

Uttar Pradesh, Bihar.

Question 17

State three advantages of black soil.

Answer 17

Black soil is rich in lime, iron, magnesium, calcium, phosphorus; clayey and highly moisture retentive; self-ploughing.

Question 18

Why is black soil ploughed in May and not in June?

Answer 18

In May, the soil dries and develops deep cracks, making it easy to plough. In June, it becomes sticky after rain.

Question 19

Why is black soil called black cotton soil?

Answer 19

It is suitable for cotton cultivation as it is moisture retentive and rich in minerals.

Question 20

Why is black soil called self-ploughing?

Answer 20

In May, the soil develops deep cracks and turns itself over, exposing underlying layers.

Question 21

Why is black soil moisture retentive?

Answer 21

Because it is clayey.

Question 22

Why is black soil suitable for dry farming?

Answer 22

Because it is clayey, moisture retentive, and found in low rainfall areas.

Question 23

Name two crops and two states where black soil is found.

Answer 23

Crops: Cotton, jowar. States: Maharashtra, Gujarat.

Question 24

How is black soil formed?

Answer 24

It is formed due to weathering of volcanic basalt rock.

Question 25

Why is red soil red in color?

Answer 25

The red color is due to the presence of iron oxides.

Question 26

Name two states where red soil is found.

Answer 26

Tamil Nadu, Karnataka.

Question 27

What is dry farming? Why is it practised on red soil areas?

Answer 27

Dry farming is ploughing the soil deeply for rainwater to seep lower. It is practiced on red soil areas due to its friable nature.

Question 28

How is red soil formed?

Answer 28

It is formed due to weathering of crystalline metamorphic rocks like gneiss.

Question 29

State an advantage and a disadvantage of red soil.

Answer 29

Advantage: Responds well to fertilizers and is easily ploughable. Disadvantage: Lacks nitrogen and soluble salts.

Question 30

Why is red soil acidic?

Answer 30

Because it lacks bases (soluble salts).

Question 31

Name two crops grown in red soil.

Answer 31

Potatoes, groundnuts.

Question 32

How is laterite soil formed?

Answer 32

It is formed due to desilication or leaching, where rainwater carries soluble salts from topsoil.

Question 33

Why is laterite soil infertile?

Answer 33

Topsoil contains iron and aluminum compounds not useful for plants; it lacks nitrogen and moisture retention.

Question 34

Why is laterite soil not moisture retentive?

Answer 34

It is not moisture retentive due to its coarse texture.

Question 35

Where is laterite soil found?

Answer 35

Summits of western ghats, Garo, Khasi, and Jaintia hills of Meghalaya.

Question 36

Name two crops grown in laterite soil.

Answer 36

Cashew, Tea.

Question 37

Explain zone of eluviation and illuviation in soil.

Answer 37

The zone of eluviation is where soluble salts are removed; the zone of illuviation is where these salts accumulate.

Question 38

What is soil erosion?

Answer 38

Soil erosion is the removal of soil particles due to natural and man-made factors at a rate faster than new soil is formed.

Question 39

Explain two natural and two man-made factors of soil erosion.

Answer 39

Natural factors: Steep slopes increase erosion; seasonal rainfall washes away soil. Man-made factors: Deforestation removes tree roots; overgrazing removes vegetation.

Question 40

What is gully erosion? Why is it harmful?

Answer 40

Gully erosion occurs when rainwater forms deep ravines. It is harmful as it leads to large soil loss and uneven landscapes.

Question 41

What is a landslide?

Answer 41

It is the sudden downward movement of weathered rock debris and soil on a steep slope, usually triggered by heavy rainfall.

Question 42

Why should soil erosion be controlled?

Answer 42

Soil needs to be conserved as it is essential for crop cultivation; excessive erosion can choke rivers and cause flooding.

Question 43

Explain contour ploughing, terrace farming, strip cultivation, and shelter belt.

Answer 43

• Contour ploughing: Ploughing along elevation to slow soil creep.
• Terrace farming: Cutting hills into steps to slow rainwater.
• Strip cultivation: Alternating crops in rows to prevent wind erosion.
• Shelter belt: Planting trees to reduce wind speed and soil erosion.

Question 44

Name two areas affected by erosion due to running water.

Answer 44

Western slopes of the Western Ghats and Chambal valley.

Question 45

Suggest methods to control soil erosion.

Answer 45

Afforestation: Planting trees. Avoidance of fallow: Continuous planting. Contour bunding: Building low mud walls. Plugging of gullies: Creating plugs to reduce soil movement.