Video narration
Why can two soils receive the same watering, yet one dry out much faster than the other? A kitchen sponge gives us a picture. Its spaces take in water, hold some, and release it when squeezed. Soil works through spaces too. With few connected spaces, water drains away quickly. With more varied spaces, some water stays longer. Here's the turn: soil organic matter isn't just extra material; it changes soil's spaces. As plant and animal material decays, it helps particles form stable clusters, creating and protecting sponge-like spaces. Some water drains; some remains where roots can reach it. But not every drop is available. Water held too tightly is out of reach. Sandy soil often shows this improvement clearly, though texture changes the result. So why does organic matter improve water-holding capacity? It helps soil build a sponge-like network that stores and releases water, keeping plants supplied longer.