Macropores of soil (diameter more than 20 `mum`) take part in

Options

A. Holding air
B. Holding air and percolation of water
C. Perolation of water
D. Holding of capillary water.

Answer

**Step-by-Step Solution:**

1. **Understanding Macropores**: Macropores are soil pores with a diameter greater than 20 micrometers (µm). They are significant in determining the physical properties of the soil.

2. **Soil Types and Their Properties**: Different types of soil have varying sizes of particles and pore spaces. For instance, clayey soil has very small particles and high water retention capacity, while sandy soil has larger particles and lower water retention.

3. **Water Holding Capacity**: Since macropores are larger than 20 µm, they are not characteristic of clayey soil, which is known for its high water holding capacity due to its fine particles. Instead, macropores are found in sandy or loamy soils.

4. **Air and Water Movement**: Macropores facilitate the movement of air and water through the soil. They allow for better aeration and drainage, which is essential for plant roots and soil organisms.

5. **Percolation of Water**: The presence of macropores means that water can percolate through the soil more efficiently. This is important for groundwater recharge and for preventing waterlogging.

6. **Conclusion**: Therefore, macropores in soil (with a diameter greater than 20 µm) primarily take part in allowing air and water movement, enhancing drainage, and supporting the overall health of the soil ecosystem.

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