✅ Answer: A) Alluvial soilAlluvial soil is the most widespread soil in India, covering about 43% of the total land area. It is found in the Northern Plains, river deltas, and coastal plains. It is the most fertile soil and supports the largest population. It is formed by the deposition of alluvium by rivers.

✅ Answer: B) CottonBlack soil (Regur) is best suited for cotton cultivation — hence it is also called “Cotton Soil.” It has high moisture retention capacity, which is ideal for cotton. It is formed from the weathering of Deccan Trap (volcanic lava). It is found in Maharashtra, Madhya Pradesh, Gujarat, and parts of Andhra Pradesh.

✅ Answer: B) Cracks in dry season, swells in wet seasonThe “self-ploughing” property of black soil refers to its ability to crack in the dry season (forming deep cracks) and swell in the wet season (absorbing water). This natural process mixes the soil layers, similar to ploughing. The cracks can be 10-15 cm wide and 1-2 metres deep. This is due to the high clay content (montmorillonite clay).

✅ Answer: C) LeachingLaterite soil is formed by leaching — heavy rainfall washes away silica, lime, and other soluble minerals, leaving behind iron and aluminium oxides. This gives the soil a reddish colour and brick-like texture when dry. The word “laterite” comes from the Latin “later” meaning brick. It is found in Western Ghats, NE India, and Odisha.

✅ Answer: B) Iron oxide (ferric oxide)The red colour of red soil is due to the presence of iron oxide (ferric oxide/Fe₂O₃). When the soil is wet, it appears yellow. Red soil is found in the Peninsular India — Tamil Nadu, Andhra Pradesh, Karnataka, and Odisha. It is porous, less fertile, and acidic. It is suitable for groundnuts, millets, and tobacco.

✅ Answer: B) Reh, Usar, or ThurSaline/alkaline soils are locally known as Reh, Usar, or Thur. They have high salt content and are infertile. They are found in arid and semi-arid regions, coastal areas, and waterlogged areas. They can be reclaimed by leaching (washing with water), adding gypsum, or growing salt-tolerant plants.

✅ Answer: C) Laterite soilTea and coffee are mainly grown in laterite soil. Laterite soil is acidic and well-drained, which is ideal for tea and coffee cultivation. Tea is grown in Assam, West Bengal, and Nilgiris. Coffee is grown in Karnataka, Kerala, and Tamil Nadu. Cashew and rubber are also grown in laterite soil.

✅ Answer: C) Gully erosionThe Chambal ravines are an example of gully erosion — deep channels formed by running water. Gully erosion is the most severe form of water erosion. The Chambal ravines in MP and Rajasthan cover thousands of square kilometres and have made the land uncultivable. They are also known as “bad lands.”

✅ Answer: B) Calcium, Magnesium, and PotassiumBlack soil is rich in Calcium, Magnesium, Potassium, and Iron. However, it is poor in Nitrogen, Phosphorus, and Organic matter. This is why cotton grows well in black soil (cotton needs potassium) but nitrogen fertilisers need to be added. The high calcium content makes it slightly alkaline.

✅ Answer: B) Kerala, coastal Odisha, and SundarbansPeaty/marshy soils are found in Kerala (backwaters), coastal Odisha, and the Sundarbans (West Bengal). They have high organic matter content, are waterlogged, and are acidic. They are black in colour. Rice is the main crop grown in peaty soils. They are also found in parts of Uttarakhand and Bihar.