The correct option is 2 and 3 only.
Explanation
Climate is a critical active factor in soil formation (pedogenesis). Temperature and precipitation directly influence the rate of weathering, the nature of chemical reactions, and the movement of solutes within the soil profile.
Statement-wise Analysis:
- Statement 1 is Incorrect. Precipitation is vital for soil formation. Water acts as a medium for chemical reactions (such as hydrolysis, hydration, and solution) and supports biological activity. Without adequate moisture, chemical weathering and biological decomposition of organic matter are significantly retarded.
- Statement 2 is Correct. In regions with high rainfall, excess water moves downward through the soil profile. This process, known as eluviation or leaching, transports dissolved minerals and fine soil components (like clay) from the upper layers to the lower layers (illuviation).
- Statement 3 is Correct. In arid and semi-arid climates, high temperatures cause evaporation to exceed precipitation. This leads to the upward movement of groundwater through capillary action. As the water evaporates at the surface, dissolved salts are left behind, leading to the accumulation of saline crusts (salinization) or hardpans (e.g., Kankar).
Key Takeaway:
Precipitation drives the downward movement of soil components (leaching) in humid climates, while high evaporation drives the upward movement and accumulation of salts (capillary action) in arid climates.