What’s happening under our feet?
Earthworms are vital in breaking down detritus, putting nutrients back into the soil, spreading nutrients about, helping with drainage, soil aeration, providing habitats for other soil-dwelling organisms, and breaking down the soil’s structure. Recent studies have found that even relatively poor soil can sustain in excess of 250 000 earthworms per acre, and fertile soil could hold seven times that amount.
One of the most important ways in which earthworms benefit the soil, though, is their ability to digest just about every type of organic plant material. With the aid of a chemical in their stomach called drilodefensins, they can digest and break down even the most poisonous of plant leaves. Drilodefensins are thought to be unique to earthworms and counteract polyphenols, which is an antioxidant produced by plants that inhibits the enzyme activity that aids digestion in many other species of herbivore.
The Earthworm’s Role
The role of the earthworm can be categorised as follows:
Biological: This is one of the worm’s most important functions, as they recycle large pieces of organic matter into micronutrient-rich humus. This humus is then pulled into the soil where it is either ingested by the earthworm or breaks down naturally. You may be interested to hear that an earthworm can process up to five times its weight in food per day. In other words, 1000 earthworms could munch their way through 1.5kg of waste per week. Imagine what that does for your compost heap!
Chemical: Earthworms consume minute soil particles that are broken down and then excreted in the form of castings. Theses casts are five times richer in available nitrogen, seven times richer in available phosphates, and 11 times richer in available potassium than the surrounding upper 150mm of soil. In good soil, an earthworm can produce up to 4.5kg of casts per year.
Physical: Their burrowing activity greatly influences the composition of the soil. Not only do they move microbes such as bacteria around, but they also take nutrients from the surface level to deeper down in the soil. They also break down clumps of soil into smaller particles, and their tunnelling helps with water absorption, preventing runoff, and also aerating the soil. The tunnels may also create microhabitats for other arthropods.
Supplied by The Gardener Magazine. For more on Erathworms click |HERE| or on the cover of the March issue of The Gardener