Question

Sheet erosion is caused by
(a)Sea
(b)Wind
(c)Heavy rains
(d)Glaciers

Answer 1

Hint: Sheet erosion is also known as sheet wash and may be characterized by the formation of channels that can be even 30cm deep. It results in the loss of a highly nutritive layer of soil rich in minerals and organic compost.

Complete answer:
The removal of a uniform layer of soil from the topmost surface of the earth due to the very high intensity of rainfall is known as Sheet erosion. It is named so because it involves a shallow layer of rainwater flowing like a sheet over the ground and is mainly seen over coastal plains, hill slopes, flood plains, and beaches.
It occurs very rarely but causes huge loss of soil in both cultivated and non-cultivated areas. The soil particles get detached from the original place by the large raindrops (rain splash) and get deposited elsewhere.

Soil erosion can be prevented by taking the following measures:
-It can be prevented by maintaining a healthy plant cover over the soil. It prevents splash erosion.
-It can be prevented by maximizing the infiltration of water on the pond by absorption through soil and organic matter.
-The organic matter consists of small pores and acts as a glue to hold the rainwater into the soil particles and reduce the amount of rainwater available for erosion.
-It can also be prevented with the help of geotextiles or mulch.

So, the correct answer is ‘Heavy rain'.

Note:
-The water flowing in sheet erosion forms certain fingers like grooves or channels known as 'rills' that can be upto 30 cm deep. Several rills converge to form grooves deeper than 30 cm known as gullies.
-The measurement of the dimension of the rills helps in determining the amount of soil eroded.
-It can be prevented by a specific variety of grass called ‘vetiver'.