Geography, asked by maria9, 1 year ago

How soil is formed? explain

Answers

Answered by Ankit1234
29
What is Soil ?
Soil is the upper weathered mineral and humus containing past of earth's crust which support plant life and contains several living organisms and their remains. 


Formation of soil :
The formation of soil depends on the parent rock material, the climate and topography of the area, the organisms found in the soil and the time over which the soil has been developing. Over long period of time, thousands and millions of years the rock near the surface of the Earth are broken down by different physical, chemical and some biological processes. The end product of this breaking down is the fine particles of soil.

Factor or processes for soil formation :
 
 (i). The sun : 
The sun heats up rocks during the day such that they expand. At night, the rocks cool down and contract. The unequal expansion and contraction in various parts of the rock results in the formation of cracks and ultimately rocks split up into smaller pieces.

(ii). Water : Water helps in the formation of soil in two ways :    Firstly, water could get into the cracks in the rocks formed because of uneven heating by the Sun. If this water freezes, it will widen the cracks.  
 Secondly, fast flowing water carries big and small particles of rock downstream, leads to breakdown of rock particles into smaller, finer particles through their abrassive effect.


(iii). Wind : Strong winds also erode rocks down. They also carry sand from one region to the other like the water does.

(iv). Living organisms : Living organisms also influence the formation of soil. While lichens grow on surface of rocks, they release some substance that cause the rock surface to powder down and form a thin layer of soil. Likewise, small plants like moss and roots of big trees also split the rocks.


Composition of soil :
Composition of soil means what makes up the soil.
 
 Soil is a mixture of :-
  --- Air
  --- Water
  --- Rock particles/ minerals
  --- humus


Types of Soil :
There are many types of soil. Some are given as follow :
 1. Sand
 2. Silt
 3. Clay
 4. Loam
 5. Gravel
 6. Peaty
 7. Chalky


Soil Erosion :
The process of carrying away the upper fertile layer of soil by air and wind is known as Soil Erosion.

Causes of Soil Erosion:
Soil Erosion is caused by following processes.
  --- Water flowing downhill
  --- Wind
  --- Deforestation
  --- Overcropping
  --- Overgrazing 
  --- Soil exhaustion 


Effect of Soil Erosion :
Effect of soil erosion are as follow :
 --- The loss of soil
 --- Breakdown of the soil structure
 --- A decline in organic matter
 --- Sedimentation Downstream
 --- Risk of flooding.


Prevention of Soil Erosion:
Prevention of Soil Erosion are as follow.

1. To grow maximum crops
2. To prevent excessive grazing
3. To prevent felling down the tree as well as planting new tree.
4. To keep the fertility of the soil.

Ankit1234: mark as brainliest
Answered by duragpalsingh
20
Need of Soil:


The conception of the term fertility has been changing over time and nowadays it is closer to the concept of productivity than to something else. That is, what offers nutritional potential to a soil is not only its nutrient content, but all those chemical, physical and biological factors that influence the availability and accessibility of nutrients by the plant. With relative frequency it is forgotten that the secret to achieve the concrete expression of all the potentiality of a soil lies in contributing to the articulated action of each of its particular fractions. That is, you have to know each of these components of the soil and above all, how they are interacting with the rest so that, through management, they can achieve their best expression.


High crop yields are the result of multiple factors that begin with a good diagnosis of soil fertility and irrigation water quality. It is important to use an adequate sampling system, a good analytical procedure and a reasonable analytical quality control in the laboratory. The next step is to perform a good interpretation of the results of the analyzes and subsequently generate an adequate recommendation of the fertilization, from a determined performance goal. The other factors involve a convenient management of conventional or conservation tillage, an adequate decision regarding genotypes and dates of planting to be used, an adequate arrangement of the plants in the field to capture the greatest amount of radiation, a correct A decision on fertilization forms and times, adequate management of crop health, good water supply and adequate soil aeration .


Formation of soil:

The main cause of soil formation is weathering, which involves the alteration of rocks in contact with water, air and living things. They can be distinguished:

Physical weathering or mechanical weathering is one that occurs when, as temperatures drop, the water in the cracks of the rocks freezes. This increases its volume and causes the fracture of the rocks.
Chemical weathering is one that occurs when rocky materials react with water or with substances dissolved therein.
Biological activity can contribute to both physical and chemical weathering.
Soil can form and evolve from most rocky materials, provided they remain in a certain position long enough to allow for the previous stages. You can differentiate:

♦ Autochthonous soils, formed from the alteration of the rock below.

♦ Allochthonous soils, formed from materials from separate sites. They are mainly soils of valley bottoms whose mineral matrix comes from the erosion of the slopes.
Soil formation is a process in which rocks are divided into smaller particles by mixing with decomposing organic matter. The bedrock begins to be undone by the cycles of ice-melting, rain and other forces of the environment:

♦ The bed of parent rock decomposes into smaller particles.

♦ The organisms of the zone contribute to the formation of the soil disintegrating it when living in it and adding organic matter after its death. As the soil develops, layers called horizons are formed.

♦ The horizon A, closer to the surface, is usually richer in organic matter, while the C horizon contains more minerals and still resembles the parent rock. Over time, the soil can sustain a thick vegetation cover by effectively recycling its resources

♦ When the soil is mature it usually contains a B horizon, where the leached minerals are stored.
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