Earthworms, vital to the health of soil, prefer soil that is approximately neutral on the acid-to-alkaline scale
Since decomposition of dead plants makes the top layer of soil highly acidic, application of crushed limestone, which is highly alkaline, to the soil' s surface should make the soil more attractive to earthworms
As far as soil health is concerned, aiding the decomposition of dead plants is the most important function performed by earthworms.