The question asks about the most characteristic physical property of black soil. We need to recall the general properties of black soils, also known as Regur soils, which are common in the Deccan Trap region of India.
C) High moisture retention and swelling when wet — Black soils are predominantly clayey. Clay particles have a high capacity to absorb and retain moisture. When they absorb water, the clay minerals expand, causing the soil to swell. This property makes them highly suitable for growing crops like cotton, which require consistent moisture.
The question asks about the utility of deep cracks developing in black soil during the dry season. This phenomenon is characteristic of black soils due to their high clay content and swelling/shrinking properties. We need to identify the beneficial aspect of these cracks for the soil.
D) Self-ploughing and aeration of the soil — The deep cracks formed in black soil during the dry season are a natural mechanism that allows air to penetrate the soil, improving its aeration. This process is often termed "self-ploughing" as it helps in loosening the soil and incorporating organic matter, thereby enhancing soil fertility and structure without human intervention.
The question asks about the typical nutrient composition of black soils. To answer this, we need to recall the general characteristics and chemical properties of black soils, also known as Regur soils, which are common in India.
A) Lime, iron, magnesia and alumina: Black soils are indeed rich in lime (calcium carbonate), iron (giving them their dark color), magnesia (magnesium compounds), and alumina (aluminum compounds). These are key components derived from the basaltic parent material.
The question asks to identify the Indian state where black soils are most extensively found. This requires knowledge of the geographical distribution of major soil types in India.
Correct Option: B) Maharashtra is the state where black soils are most extensively found, covering a significant portion of its land area, particularly due to its location in the Deccan Trap region.
The question asks to identify the crop best suited for black soils. This requires knowledge of the characteristics of black soils and the specific requirements of various crops.
D) Cotton — Black soils are famously known as "Black Cotton Soils" because they are exceptionally well-suited for cotton cultivation. Their high clay content allows them to retain moisture for long periods, which is crucial for cotton, especially during dry spells. They are also rich in nutrients like lime and iron, which benefit cotton growth.
The question asks about the typical texture of black soil. To answer this, we need to recall the characteristic properties of black soil, also known as Regur soil, which is common in the Deccan Trap region of India.
Based on these characteristics, option C is the most accurate description.
Correct Option: C) Clayey, deep and impermeable