Fungi are high in protein that in turn is high in nitrogen.
Nematodes that feed on fungi digest the protein they take in and convert it to a form of nitrogen that is excreted into the soil as a body waste product. This nitrogen is converted into nitrate and is available to plants. This is an example of the function of nutrient recycling that is a benefit of the soil foodweb. Where this feeding and gradual release of nitrogen occurs less applied chemical nitrogen is required during the growing season.