Soils of India — Set 1

Correct Answer: D. Alluvial Soil

Alluvial soil is the most widespread soil type in India, covering about 40% of the total land area. It is formed by the deposition of silt by major river systems like the Indus, Ganga, and Brahmaputra. This soil is highly fertile and supports the majority of India's agricultural production.

Correct Answer: A. Black Soil

Black soil is popularly known as Regur soil, a term derived from the Telugu word 'Reguda'. It is ideal for growing cotton, which is why it is also called Black Cotton Soil. This soil is largely found in the Deccan Trap region made of basaltic rock.

Correct Answer: B. Iron Oxide

The red color of this soil is due to the wide diffusion of iron in crystalline and metamorphic rocks. It develops a yellowish color when it occurs in a hydrated form. It is generally poor in nitrogen, phosphorus, and humus.

Correct Answer: B. Intense Leaching

Laterite soil develops in areas with high temperature and heavy rainfall through the process of intense leaching. This process washes away the silica and lime, leaving behind iron and aluminum oxides. It is commonly found on the summits of the Western and Eastern Ghats.

Correct Answer: D. Old Alluvium

Bhangar represents the older alluvium of the plains, often containing calcareous deposits locally known as 'Kankar'. It is found in higher reaches of the river terraces above the flood levels. In contrast, Khadar is the newer, more fertile alluvium found in floodplains.

Correct Answer: B. Black Soil

Black soil develops deep cracks during the dry season, which allows for better aeration. This phenomenon is often described as 'self-ploughing' because it helps in the mixing of soil layers. The soil becomes very sticky and difficult to work with when it is wet.

Correct Answer: C. Red Laterite Soil

Red laterite soils in states like Tamil Nadu, Andhra Pradesh, and Kerala are more suitable for tree crops like cashews. While generally less fertile for grains, they respond well to fertilizers for plantation crops. These soils are rich in iron but poor in organic matter.

Correct Answer: B. Alkaline

Desert soils are generally alkaline in nature due to high salt content and low rainfall. They lack moisture and humus, resulting in limited biological activity. With proper irrigation, such as in the Indira Gandhi Canal area, these soils can become productive.

Correct Answer: D. Peaty Soil

Peaty soils are found in areas of heavy rainfall and high humidity, where there is a good growth of vegetation. A large amount of dead organic matter accumulates in these areas, giving the soil a high humus content. These soils are often heavy and black in color.

Correct Answer: B. River floodplains

Khadar is the new alluvium deposited by floods almost every year, making it very fertile. It is primarily found in the low-lying areas of river valleys and floodplains. This soil is fine-grained and excellent for intensive agriculture.