The correct Answer is
Arid soil - accumulation of kankar in lower horizons
Explanation
Soil types exhibit distinct characteristics influenced by parent material, climate, vegetation, and topography. These characteristics include texture, chemical composition, and moisture retention capacity, which determine their suitability for agriculture.Statement-wise Analysis
Forest soil - high humus content in all regions
- Incorrect. Forest soils, particularly in coniferous forest regions, can be acidic with low humus content due to slow decomposition of coniferous litter. While some forest soils, especially in broadleaf forests, have high humus, it is not a universal characteristic across all forest regions.
Arid soil - accumulation of kankar in lower horizons
- Correct. Arid soils are characterized by dry conditions, high temperatures, and rapid evaporation. This leads to the downward movement of water carrying dissolved salts, which then precipitate and accumulate in the lower horizons as 'kankar' (calcium carbonate concretions). This accumulation restricts water infiltration.
Red soil - high nitrogen retention
- Incorrect. Red soils are typically deficient in nitrogen, phosphorus, and humus. Their nitrogen retention capacity is generally low due to the lack of organic matter and microbial activity.
Black soil - coarse texture with low moisture retention
- Incorrect. Black soils (Regur soils) are known for their fine, clayey texture. This fine texture gives them an excellent capacity to retain moisture, making them highly suitable for crops like cotton, especially during dry spells.