The correct option is (c) 2 and 3 only.
Explanation
Soil and vegetation share a symbiotic relationship within an ecosystem. Vegetation cover plays a critical role in maintaining soil structure, fertility, and stability, while soil provides the necessary medium and nutrients for plant growth. Deforestation disrupts this balance, leading to degradation.
Statement-wise Analysis:
- Statement 1 is Incorrect: The physical properties of soil (such as structure, porosity, bulk density, and water-holding capacity) are significantly influenced by vegetation. Plant roots penetrate the soil, creating channels that improve aeration and water infiltration. Furthermore, the addition of organic matter (humus) from decaying leaves and roots improves soil aggregation and structure. Therefore, vegetation directly affects the physical properties of soil.
- Statement 2 is Correct: Trees and vegetation act as natural barriers against erosive forces. The canopy intercepts rainfall, reducing the kinetic energy of water droplets before they hit the ground, while root systems bind soil particles together. The removal of trees (deforestation) exposes the soil surface to direct rainfall and wind, significantly increasing the rate of soil erosion.
- Statement 3 is Correct: Soil erosion primarily affects the uppermost layer of the soil profile, known as the topsoil (A-horizon). This layer is rich in organic matter, humus, and essential nutrients required for plant growth. When erosion occurs, this fertile layer is washed or blown away, leaving behind less productive subsoil, thereby reducing agricultural productivity and ecosystem health.
Key Takeaway:
Vegetation is essential for preserving soil physical properties and preventing erosion. Deforestation accelerates the loss of the fertile topsoil, leading to land degradation and reduced soil fertility.