Question

1 WHAT IS SOIL EROSION ? ITS 5 CAUSES AND ITS 5 PREVENTIONS.

2 WHAT IS SOIL POLLUTION. ITS 4 CAUSES AND ITS 5 PREVENTIONS.

3 DESCRIBE THE ALL HORIZONS OF SOIL PROFILE.

4 WHAT IS SOIL PROFILE.

5 DESCRIBE THREE STAGES OF WEATHERING.

6 WHAT IS SOIL FERTILITY ? HOW CAN WE IMPROVE IT ?

7 GIVE THREE CHARACTERISTICS OF CLAY SOIL , SANDY SOIL AND LOAMY SOIL .

8 DIFFERENCE BETWEEN CHEMICAL AND PHYSICAL WEATHERING.

Answer 1

1 the removal of soil by running water and wind is known as soil erosion.

MAIN CAUSES :

A)DEFORESTATION: the removal of trees on a large scale is known as deforestation. when trees are removed , soil particles are left loose and can easily be carried away by the running water and wind.

B) OVERGRAZING: repeated grazing by animals on the same patch of land without sufficient recovering periods ,leads to the removal of grass on a large scale. this makes it easy for wind and running water to Erode the soil.

C) FLOODS AND HEAVY RAINFALL : floods and heavy rainfall wash of soil especially when there are no trees and the land is lying bare .

D) IMPROPER FARMING : improper farming on Hills make it easy for wind and water to erode soil .

PREVENTION:

A) planting of trees in large number on deforested land planting of trees in large number in area where there was no forest previously. glasses and Herbs can be used to cover large patches of loose soil.

B) overgrazing by animals should be avoided. animals should be moved to different area for grazing after sometime.


C) floods can be controlled to a large extent by building dams . embankments or mud walls should be constructed around Hill slopes or mud walls should be constructed around Hill slopes or field to stop the flow of water.


D) terrace farming should be adopted in hilly areas. in this method suitable crops are grown on a slope, which is cut into large steps called terraces. this reduces the speed with which water flow down, thereby reducing soil erosion.

2 soil is one of the most valuable natural resources on earth. when it gets polluted by various means including careless human activities, necessary measures must be adopted to control the pollution.

MAJOR SOURCES

A) acid rain and acid water from factories, mines and industries.

B) improper dumping of garbage and sewage waste in soil.

C) excessive use of pesticides and fertilizers, which get accumulated in soil.





CONTROL :

A) solid waste should not be dumped on land. they should be recycle and proper measures for disposal of sewage should be adopted.

B) animal and domestic waste should be used to produce biogas.

C) instead of excessive chemical pesticides and fertilizers, organic pesticides should be used.



3

A horizon =A horizon or topsoil is the uppermost layer of soil. it consist of fine particles. it is usually rich in humus and therefore dark in colour. it is soft , Porous and can hold water. O horizon lies just about the top soil and rich in organic matter.

B horizon or subsoil= B horizon or subsoil is rich in minerals that sheep down along with water. it also contains compactly packed fine particles of soil.

C horizon = C horizon contains partly weathered pieces of rocks . it is usually characterized by cracks and crevices. it is very difficult to the ground is this layer.

R horizon or bedrock = R horizon is the lowermost layer and mainly consists of parent rock. the properties of this Rock greatly determined the composition of the soil.


4 . a vertical section of soil from the ground surface to the parent rock that shows the different layer of soil at the horizon is called for profile.


5

STAGE 1= weathering, be it physical or chemical, causes large pieces of parent Rock near the surface of disintegrate into smaller ones.

STAGE 2= smaller rocks continue to undergo further weathering , thus allowing a very fine layer of Rock particles to form at the surface of the earth.

STAGE 3= Minerals and salts SIP deeper into the ground along with water to complete the formation of soil and make it favourable for plant growth.

6 soil fertility refers to the capacity of soil to provide nutrients in adequate amount and in proper balance for growth of plants.

to make the soil more fertile

A) ALTERNATION OF pH .

B) ALTERNATION OF AIR CONTENT.

C)ADDITION OF FERTILIZERS .

7 ATTACHMENT IN PIC




8 PHYSICAL WEATHERING : in this process, rocks are broken down to form smaller pieces. it is a mechanical process and does not involve any change in the characteristic of the original rock . it may be caused by temperature differences, Frost, growing roots of plants, movement of animals etc.

CHEMICAL WEATHERING: it is a process in which the existing minerals are broken down into new mineral components. in this process the chemical nature of Rock changes. water is one of the main agents of chemical weathering.