By contrast, we must till and fertilize to create good root growth. While tilling to create looser soil for easier root growth, we destroy many roots and root hairs. The activity of the earthworm gut is like a miniature composting tube that mixes, conditions, and inoculates plant residues. The earthworm removes plant litter from the soil surface, turning it into free manure. As yet, the exact reasons are unclear, but soil with earthworms invariably has less parasitic nematodes than soil without earthworms.
Earthworms are the best indicator yet of healthy soils.
Good soils contain a wide range of beneficial organisms which are directly stimulated by the activities of earthworms. These organisms trap, strangle, eat, and simply crowd out the plant-eating nematodes. By contrast, soils without earthworms and a healthy microbiology must be fumigated prior to planting. This fumigation kills both good and bad organisms indiscriminately. When the nematodes return, and they always do, there will be little there to deter their proliferation.