can anybody give me a detailed note on the classification of soils from chp 1 in 10th geo textbook
Answers
Soil, Its Formation & Factors Affecting Soil Formation
Meaning of Soil: It is an important an renewable resource. It is upper part of the crust which is loose and fragmented. It has air, water and minerals contents and it support growth of plants. Bacteria and other small organisms are also found in the soil which makes it more fertile.
Formation of Soil: Soil is formed by weathering and erosion of rocks. Temperature and rainfall breaks down the rock into smaller parts. After mixing of water and minerals in these sediments, it acquires the form of soil. Following factors affect soil formation.
Factors Affecting Soil Formation
a) Parent Rocks: It determined the colour, texture and mineral contents in soil
b) Climate [Rainfall and Temperature]: It determines rate of weathering and erosion of rocks.
c) Topography [Slope]: On higher land thin layer of soil is found, while in the lower valley thick deposition of alluvium is found.
d) Vegetation [Plants and Trees]: They add organic matter [Humus] to the soil.
e) Time: Older soils are generally more fertile than newer soil.
Soil Erosion and Methods of Soil Conservation
Soil Erosion: Removal of top and fertile layer of soil by the agents like rainwater and wind is called soil erosion. Soil erosion is a acute problem in India. Chambal river basin is so badly eroded that this entire area is called as ‘Bad Land or Ravines’. There are three types of erosion, i.e. a) Sheet Erosion, b) Rill Erosion and c) Gully Erosion [Most Dangerous]. Followings are the reasons for soil erosion.
Reason for Soil Erosion:
a) Deforestation – Cutting down of trees and forests
b) Torrential [heavy] rainfall
c) Overgrazing by cattle
d) Unscientific agriculture [Ploughing land parallel to the slope]
e) Excessive use of chemical fertilizers and irrigation
Measurement to Check Soil Erosion:
a) Afforestation – Planting trees on degraded land
b) Plugging of gullies
c) Check on overgrazing by cattle
d) Scientific agriculture [Ploughing land at right angle of slope – Contour Ploughing]
e) Crop rotation
f) Terrace farming
g) Preparation of shelter belt
Short Note on Alluvial Soil
§ It is the most fertile and extensive soil in India.
§ It is found in the river valleys of Ganga, Yamuna, Indus and Brahmaputra.
§ This soil has been formed by deposition of sediments in the northern plain.
§ This soil is found from Punjab up to Assam. It is also found along the coastal areas.
§ Coarse soil near the mountain foothill is called duars, chos and tarai. In the plain area, lower parts are called khadar and upper parts are called banger.
§ This soil is ideal for the agriculture of rice, wheat, sugarcane, pulses and many other crops.
Short Note on Black Soil
§ This soil is formed by the weathering of lava rocks.
§ It looks black due to presence of magnesium in it.
§ It is found mainly in Maharastra, Gujarat and Karnataka [Deccan Trap].
§ Black soil has high capacity to hold moisture. It become sticky when it is wet and develop crack when it is dry.
§ It is best for the cultivation of cotton. Hence, it is called as Black Cotton Soil. It is also known as ‘Regur Soil’.