Their tunneling activity helps aerate the soil. The channels they make as they move through the soil allow rain to enter the soil more rapidly, reducing runoff and the potential for erosion. This also helps improve soil structure by creating a loose soil that is easily penetrated by roots. Worms increase the nutrients available in the soil for plants. As worms digest plant material, their castings or excrement concentrate nutrients.
Castings are several times higher in nitrogen, phosphorus, potassium, and magnesium than topsoil.
This nutrient rich material is mixed into the soil where plant roots can use the nutrients. Also, by incorporating litter into the soil, worms reduce the number of fungus spores on the soil surface and that can help prevent plant diseases such as apple scab. Like all living organisms, worms need a suitable habitat in order to thrive. Here are some suggestions to improve worm habitat in your yard. Provide worms with organic matter for a food source.