Turf - Benefits of Earthwoms

Earthworm activity in the turf areas is a sign that your soil is healthy. The following are some benefits of earthworms in turf.

In most turfgrass situations, the benefits of earthworm activity by far outweigh any negative effects. Earthworms play a vital role in the development of soil structure, fertility, and nutrient recycling. They ingest organic matter along with soil and excrete the mixture of digested organic matter and soil as castings. These casts modify soil structure by breaking down larger structural units into finer, spherical granules, and in some soils, can contribute up to 50% of the soil aggregates. Many earthworm species deposit their casts beneath the soil surface into voids and thus contribute to soil structure development. In contrast, species that build permanent, vertical burrows deposit their casts on the soil surface and contribute more to soil profile development. In some soils earthworm casting deposition on the soil surface can be equivalent to a ¼” deep uniform layer of enriched topsoil per year. Earthworms also improve the nutrient availability in soil through the digestion and liberation of nutrients and their mixing with soil and redistribution in the soil through cast deposition. The burrowing activity of earthworm improves soil aeration and drainage of excessive water and reduces soil compaction. Up to 66% of all pore space in some soils is estimated to be the result of earthworm burrowing. In turfgrass, earthworms are the major contributors to the breakdown of thatch. By feeding on decaying thatch and leaf litter they mix it with soil and stimulate its microbial decomposition. They also incorporate large amounts of soil into the thatch layer and thus improve its suitability for turfgrass growth. Thatch is rarely excessive where earthworms are abundant.

Reprinted from "Earthworms in Turfgrass" by Albrecht M. Koppenhöfer, Ph.D., Turfgrass
Entomology and James A. Murphy, Ph.D., Turfgrass Management in the October 7, 2004 edition of the Plant and Pest Advisory, Landscape, Nursery and Turf Edition from Rutgers University