I live in the northern part of the province and I give talks to people about composting. It is almost inevitable that someone will comment that they have an area of their yard that has lots of worms, but the soil is very hard. Many of these people are of the opinion that it is the worms that makes the soil hard. I believe the worms aren't responsible, but that is really just a guess, and I tell them to add plenty of compost and other organic matter. Is anyone familiar with this situation?
The worms should make the soil less heavy than it would be if they were not present. They will pull surface organic material down into the soil---nature's composting. While they are working furiously away, they are creating tunnels which help aerate of the soil. And, they are contributing their own "manure". So, they are very beneficial, not at all bad. Soil texture is determined by its make up of sand, silt and clay. The heavier the soil, the more clay that is present. Of course, compaction from heavy equipment, etc. can make it appear to be heavy when it isn't really, but your situations sound like you have clay soil.