Question

Differentiate between transported soil and in situ soil with a suitable example for each.

Answer 1

Hint: Soil is a broad term used for a layer of rock debris and organic materials that form on the earth’s surface. Various factors affect the formation of soil namely relief, parent material, climate, vegetation and other life-forms and time. Based on genesis, colour, composition and location, the soils in India have been categorised into the following—Alluvial soils, Black soils, Red soils, Laterite soils, Desert soils, Saline soils and Forest soils.

Complete answer: -Transported soil is the name given to the kinds of soil that are formed in one place but agents of erosion bring the sediment away and deposit it in another place. One example of this is alluvial soil which is formed due to silt deposited on riverbanks and floodplains. In India, the geographic area with the largest alluvial soil deposits is the Indo-Gangetic-Brahmaputra plains. The rivers Indus, Ganga, Yamuna and Brahmaputra that originate in the Himalayas bring down rocks and boulders from the mountain region which due to the water current are crushed and deposited along the plains. Because the soil has a porous texture good for drainage and is rich in minerals like potash, phosphoric acid and iron oxide, it provides favourable conditions for agriculture.
-In Situ soil, on the other hand, is formed when the rocks break into fragments but are transported too far from the parent rock. Examples of in situ soil include black soil and desert soil. Black soil is formed by the weathering of igneous rocks and solidification of lava from volcanic eruptions which is why they have not transported away from the parent rocks. They are rich in lime, iron, magnesia and alumina and have a clayey, deep and impermeable nature. In India, black soil covers almost the entire Deccan Plateau and is very favourable for growing cotton.

Note: The decline in soil fertility due to degradation in its quality and erosion of the top layer has become a widespread issue. These issues are often caused by human activities like deforestation or overgrazing, however, they can also take place due to natural calamities. With the increase in the human population, large areas of natural vegetation are being converted into settlements, industries or agricultural land which aggravates soil erosion.