The correct option is Arid soil.
Explanation
Soil formation is heavily influenced by climatic conditions such as temperature and rainfall. In regions characterized by high temperatures and low precipitation, soils develop distinct physical and chemical properties, particularly regarding moisture content and salinity.
Detailed Analysis:
- Arid Soil Characteristics: Arid soils (also known as Desert soils) are typically sandy in texture and saline in nature. They range from red to brown in colour.
- Impact of Climate: Due to the dry climate and high temperatures, evaporation is accelerated. This process leaves behind salts in the upper layers of the soil and results in a distinct lack of moisture and humus. In some areas, the salt content is sufficiently high to extract common salt through evaporation.
- Cultivability through Irrigation: The lower horizons of arid soil often contain 'Kankar' (calcium carbonate nodules), which restricts water infiltration. However, these soils possess mineral nutrients. When proper irrigation is introduced-as demonstrated in Western Rajasthan with the Indira Gandhi Canal-the soil moisture is restored, and salinity is managed, making the land suitable for cultivation.
Comparison with Other Options:
- Laterite soil: Develops in areas of high temperature and heavy rainfall. It is formed through intense leaching, which removes silica and lime, leaving it acidic and rich in iron oxide. It is not associated with arid, saline conditions.
- Black soil: Characterized by a clayey texture and high moisture-retention capacity. It is naturally fertile and self-ploughing, primarily found in the Deccan trap, and does not require irrigation to overcome initial unsuitability due to salinity.
- Forest soil: Found in hilly and mountainous regions. These soils vary in texture but are typically acidic with low humus in snow-bound areas. They are not defined by high salinity caused by evaporation.
Key Takeaway: Arid soils are initially unsuitable for agriculture due to high salinity, sandy texture, and lack of moisture caused by high evaporation; however, they become cultivable with the application of proper irrigation techniques.