Which one of the following soil types in India is traditionally known as black cotton soil and is considered particularly suitable for cotton cultivation?

Introduction / Context:
Different crops grow best in different soil types, depending on texture, structure, nutrient content and water holding capacity. Cotton is a major cash crop in India that requires a soil capable of retaining moisture and supporting deep roots. In Indian geography, black soils, often called regur, are famous as black cotton soils precisely because they are well suited to cotton cultivation. This question asks you to identify which soil type is suitable for cotton production.

Given Data / Assumptions:
• Soil types listed are Kankar, Regur, Bhangar and Khadar. • Cotton is the crop under consideration. • We assume standard definitions of these soil names in Indian geography. • The question expects the classical pairing of cotton and black cotton soil.

Concept / Approach:
Regur soil is a local term used for black soils formed over Deccan basalt. These soils are rich in clay and have a high capacity to retain moisture due to their swelling and shrinking properties. This makes them particularly suitable for cotton, which needs moisture supply during its growing period. Kankar soil refers to calcareous deposits in semi arid soils, while Bhangar and Khadar are older and newer alluvial soils respectively, mainly in the northern plains. Alluvial soils support many crops but are not specifically labelled black cotton soils. Therefore, Regur or black soil is the correct answer.

Step-by-Step Solution:
Step 1: Recall that black cotton soils are concentrated in Maharashtra, Madhya Pradesh, parts of Gujarat and the Deccan plateau, where cotton is widely grown. Step 2: Remember that the technical or local name often used for this black soil is regur. Step 3: Note that Kankar refers to nodules of calcium carbonate present in some semi arid soils and is not the main soil type for cotton. Step 4: Understand that Bhangar and Khadar are older and newer alluvial soils of the northern plains, good for many crops but not classically called black cotton soils. Step 5: Conclude that Regur or black cotton soil is the one especially suitable for cotton cultivation.

Verification / Alternative check:
Indian geography textbooks explicitly state that black soils are called black cotton soils because cotton is traditionally grown on them. They emphasise the high water retaining capacity and the fine clay texture that help cotton plants survive dry spells. In contrast, discussions of Bhangar and Khadar focus more on cereal and sugarcane cultivation in the alluvial plains. Therefore, exam keys consistently match cotton suitability with regur soil.

Why Other Options Are Wrong:
Kankar soils contain lime nodules and are found in drier regions where calcareous concretions form; they are not identified as ideal cotton soils. Bhangar alluvial soil is the older alluvium of the northern plains and, while fertile, is not the classical black cotton soil associated with cotton. Khadar alluvial soil is newer, younger alluvium deposited by rivers and is excellent for crops like wheat and rice, but again is not the black cotton soil of Deccan.

Common Pitfalls:
Candidates sometimes assume that since alluvial soils are fertile, they must be the best for every crop, including cotton. This leads them to choose Bhangar or Khadar. Another mistake is to ignore local soil names such as regur. The key fact to memorise is that black soil equals black cotton soil or regur, and it is specially associated with cotton cultivation in the Deccan plateau.

Final Answer:
The soil suitable for cotton production is Regur or black cotton soil.