Why does water poured onto already moist potting soil soak in faster than water poured onto completely dry potting soil?

Question

Why does water poured onto already moist potting soil soak in faster than water poured onto completely dry potting soil?

In: Earth Science

Answer 1

Wet soil clumps, creating gaps for the water to pour into.

When the soil dries it separates again and spreads out to create a broadly uniform layer (thanks, gravity!). That makes a barrier for the water.