Black soil is ideal for cultivation of cotton as?

Appeared in: RRB Staff Nurse Mumbai-2015

Explanation

Black soil, also known as Regur soil, is ideal for cotton cultivation due to its high moisture-retention capacity.
It has a high proportion of clay, which allows it to hold water for long periods, ensuring a steady supply of moisture to the cotton crop's roots.
This property is especially beneficial in the rain-fed areas of the Deccan Plateau where the crop is extensively grown.
When dry, the soil develops deep cracks, which helps in deep aeration, a phenomenon known as 'self-ploughing'.

Option A: The black color is a result of its iron content and origin from lava rocks, but the color itself does not contribute to its suitability for cotton cultivation.
Option C: While it is true that black soil is formed from weathered lava rocks, this describes its origin, not the specific property that makes it ideal for cotton. Its moisture-retaining ability is a consequence of its origin.
Option D: This statement describes the geographical location where black soil is commonly found (Deccan Plateau). It does not explain why the soil itself is good for growing cotton.

Visual 1: Map of India showing the distribution of black soil, highlighting the Deccan Plateau region.
Visual 2: Diagram illustrating the properties of black soil: showing its texture, moisture retention, and the 'self-ploughing' cracks when dry.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Properties of Black Soil for Agriculture as background academic context rather than a clinical decision trigger.
Understanding soil types is fundamental to agriculture and geography, explaining why certain crops are dominant in specific regions of India.
The 'self-ploughing' nature of black soil (developing deep cracks when dry) is another beneficial property, as it aids in soil aeration without manual tilling.
What if the crop was rice? Black soil would be less ideal for rice, which requires standing water. Alluvial soils, which are found in river deltas and are highly fertile and can be puddled, are better suited for rice cultivation.

How to Approach the Question

Identify the core question: Why is black soil 'ideal' for cotton?
Analyze the options to see which one provides a functional reason directly related to crop growth.
Option A (color) is a physical characteristic, not a functional benefit.
Option B (moisture retention) is a direct functional benefit for a thirsty crop like cotton.
Options C (origin) and D (location) are true facts about the soil but are not the direct reason for its agricultural suitability. They are background facts, not the immediate mechanism of action.
Select the option that explains the direct mechanism of support for the plant's needs.

Concept Tested & Keywords

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Practise the full RRB Staff Nurse Mumbai-2015

Attempt every question from this paper in a timed mock, then review the full solution for each one.