The correct option is 2 and 3 only.
Explanation
Soil formation (pedogenesis) is an exogenic process driven by weathering and the accumulation of organic matter. The concept of soil maturity refers to the extent to which a soil has developed distinct structural and compositional layers, known as horizons, over time.
Statement-wise Analysis:
- Statement 1 is Incorrect: Time is a critical factor in soil formation. A soil formed in a very short period is generally considered immature because there has been insufficient time for physical, chemical, and biological processes to differentiate the parent material into distinct horizons.
- Statement 2 is Correct: A soil is classified as mature when it develops a clear soil profile. A profile consists of distinct horizontal layers (horizons A, B, and C) that differ in texture, structure, and chemical composition. The presence of these horizons indicates that pedogenic processes have operated for a sufficient duration.
- Statement 3 is Correct: Soils formed from recently deposited materials, such as alluvium (river deposits) or glacial till, are considered immature. These soils exhibit little to no variation in vertical horizons because the deposition is too recent for significant weathering or profile development to have occurred.
Key Takeaway:
Soil maturity is defined by the presence of a well-developed soil profile with distinct horizons. Immature soils lack these horizons, typically due to insufficient time for pedogenesis or constant depositional disturbance.