Mulches prevent soil splashing, which not only stops erosion but keeps soil-borne diseases from splashing up onto the plants. Organic mulches can improve the soil structure. As the mulch decays, the material becomes topsoil. Decaying mulch also adds nutrients to the soil. Mulches prevent crusting of the soil surface, thus improving the absorption and movement of water into the soil.
Mulches prevent the trunks of trees and shrubs from damage by lawn equipment.
Mulches help prevent soil compaction. Mulches can add to the beauty of the landscape by providing a cover of uniform color and interesting texture to the surface. Mulched plants have more roots than plants that are not mulched, because mulched plants will produce additional roots in the mulch that surrounds them. Both types may have their place in the garden. An organic mulch is a mulch made of natural substances such as bark, wood chips, leaves, pine needles, or grass clippings.