It makes the surface soil

2 It makes the surface soil

2. It makes the surface soil, or topsoil, deeper. It stands to reason that the deeper the soil the more plant food becomes available for plant use.

3. It improves the texture of the soil. Wet soil is sticky. Drainage makes this sticky soil crumble and fall apart.

4. It prevents washing.

5. It increases the porosity of soils and permits roots to go deeper into the soil for food and moisture.

Fonte: Agriculture for Beginners