Soil Erosion And Conservation - 2 Class 5 Worksheet Science

Q1: Fill in the blanks.

(i) _______ of rocks and stones over many years results in the formation of soil.
Ans: Weathering

(ii) The removal of fertile top soil is called _________.
Ans: Soil erosion

(iii) _________ and _________ are the two main causes of soil erosion.
Ans: Wind and water

(iv) _________ acts as a soil-binders to prevent soil erosion.
Ans: Roots

(v) _________ of hill sides loosens the soil helping in soil erosion.
Ans: Ploughing

(vi) In between crops called the ________ crops can be grown to protect the soil.
Ans: Cover

(vii) Earth Day is celebrated every year on __________.
Ans: April 22nd

(viii) The Hwang Ho river which changes its course every year is in __________.
Ans: China 

Q2: Multiple Choice Questions (MCQs).

(i) Which of the following is NOT be found in topsoil?
(a) humus
(b) minerals
(c) sediment
(d) bedrock
Ans: (d)

(ii) Sand dune is a major feature of ______________ erosion.
(a) water
(b) gully
(c) coastal
(d) wind
Ans: (d)

(iii) The properties of soil
(a) are similar in all layers.
(b) are different from place to place.
(c) are the same in all environments.
(d) can only be observed with scientific equipment.
Ans: (b)

(iv) Why is it important to have soil conservation
(a) save the soil
(b) prevent erosion
(c) prevent another dust bowl
(d) all of the above
Ans: (d)

(v) Soil is mostly conserved by _______.
(a) afforestation
(b) deforestation
(c) making dams
(d) overgrazing
Ans: (a)

(vi) A wall or fence of earth or stone built to prevent a river flooding an area is known as
(a) barrier
(b) step farming
(c) Dam
(d) Embankment
Ans: (d)

(vii) Human activities that increase soil erosion include
(a) mining
(b) overgrazing by cattle
(c) afforestation
(d) Both mining and overgrazing by cattle
Ans: (d)

(viii) The solid rock that forms Earth's surface is called
(a) sediment.
(b) bedrock.
(c) clay.
(d) sand.
Ans: (b)

Q3: Answer the following Questions.

(i) Why good humus in the soil, prevent it from wind erosion?
Ans: Wind erosion is when the wind lifts and removes topsoil. In dry areas in particular, soil that is not kept in place by plants is easily removed by the wind. It usually takes place in dry soil, where the humus content is very low.
Higher humus contents keep the particles closer together, so that wind can only induce erosion at very high wind speeds. Soils with higher humus contents, retain rainwater better than soils with little humus. A soil surface that does not immediately run dry after rainfall is much better able to defy wind erosion. Soil with higher humus content is able to retain more water, which keeps the soil together by adhesive forces like a glue, so the wind cannot remove the soil easily

(ii) What is soil erosion? Name some means of preventing it.
Ans: The removal and transportation of the top layer of soil from its original position to another place, under the effect of strong winds and fast running rainwater is called soil erosion.
Soil erosion can be prevented by:

• Intensive cropping
• Sowing grasses and planting xerophytes.
• Terrace farming.
• Contour bunding.

(iii) The rivers, sea waves and wind are the natural agents that cause soil erosion. Why has the soil erosion increased?
Ans: The main cause of soil erosion are: Deforestation, overgrazing, shifting cultivation, using top soil for making bricks and tiles. These cause the soil to become loose. Thus the top layer of soil flows away easily with the wind or rivers.

(iv) Explain a few ways to prevent soil erosion.
Ans: 

• Planting/Vegetation: Planting vegetation can control and prevent soil erosion by holding on to soil particles and preventing them from being eroded.
• Fertilizer Use: Fertilizers can stop soil from eroding by adding an extra layer of protection.
• Retaining Walls: Constructing retaining walls around places where soil erosion is a problem can help to reduce the amount of soil eroded.
• Permeable fabric materials, such as coir, can be used to strengthen the soil and prevent erosion.

(v) What causes soil erosion?
Ans: 

• Soil erosion is the loss of the fertile soil due to an absence of plants which can hold the soil.
• The roots of the plants allow the soil to be held due to the presence of water. In deforestation, there is the cutting or the removal of plants.
• Due to which the water present in the soil gets evaporated resulting in a barren land.
• This barren land is prone to soil erosion which results in the loss of the upper layer of the soil.