According to the Department of Primary Industries, the presence of worms improves the quality of the soil and leads to better plant growth. As worms are decomposers, the dead organic material they eat in an area becomes concentrated within their digestive tracts, and they release nutrient-rich casts into the soil.
These casts provide ample food for plants and also help create additional layers of topsoil over a period of years. Worms, through their burrowing, contribute to improved soil drainage, leading to a better distribution of water within the area. Their passageways also serve as paths for minerals and provide improved nitrogen intake.