Earthworms can eat their weight in organic matter and soil each day to create nutrient rich castings. Earthworms help create humus—a dark brown-black type of soil which holds important nutrients in place for plant growth and use.

Humus – soil – plants: Earthworms

1. Directly: by ingestion, digestion, and excrement production.
2. Indirectly: by affecting the populations of microorganisms by eliminating their enemies or using their nutrients, influencing soil moisture and aerating, or by pulverizing and transferring plant material.

Earthworms need the food and habitat provided by surface residue, and they eat the fungi that become more common in no-till soils. As earthworm populations increase, they pull more and more residue into their burrows, helping to mix organic matter into the soil, improving soil structure and water infiltration.

2) Earthworms are great “soil engineers”. As they move through the soil, earthworms loosen and mix it up, helping to aerate and drain it. This brings nutrients to the surface, making the soil more fertile, and helps prevent flooding and erosion. 3) Earthworms are barometers of soil health and toxicity.

Earthworms’ casts also improve soil structure and nutrient availability—which increases garden productivity! They are breaking up leaft litter and other debris to recycle nutrients back to the soil. Their movement mixes up the soil while creating a network of burrows to help air and water move through the soil.

Soil Condition Because earthworms breathe through their skin, it must be kept moist in order to work. Dry skin stops the diffusion process, effectively preventing earthworms from getting oxygen. That is why worms are so commonly spotted above ground when it is rainy and at night, when air is wetter.

Worms aerate the soil, allowing better circulation. They also eat organic material, so a big worm population means your soil is rich in nutrients. Look for earthworm casts or burrows on the surface of damp soil.

They also help incorporate organic matter into the mineral soil to make more nutrients available to plants. However, in agricultural settings earthworms can also have harmful effects. For instance, their castings (worm excrement) can increase erosion along irrigation ditches.

They burrow during the day—typically keeping close to the surface—capable of digging down as deep as 6.5 feet. The worm’s first segment contains its mouth. As they burrow, they consume soil, extracting nutrients from decomposing organic matter like leaves and roots.

Earthworms like moist soil. They can survive in dry soils but they are not active. However if the drought is severe, they will die. In dry conditions, they can burrow deep into the soil to 1 metre, tie themselves in a knot, secrete a coating of mucous about themselves which dries and helps prevent water loss.

Earthworms are hermaphrodites; that is, they have both male and female sexual organs. The sexual organs are located in segments 9 to 15. Earthworms have one or two pairs of testes contained within sacs. The two or four pairs of seminal vesicles produce, store and release the sperm via the male pores.

They tunnel deeper into the ground. Earthworms need moisture to survive, so they spend most of their lives underground, in the top three feet of soil. At those depths, they usually have the moisture they need as well as leaves and other dead plant material to eat.

If an earthworm is split in two, it will not become two new worms. The head of the worm may survive and regenerate its tail if the animal is cut behind the clitellum. But the original tail of the worm will not be able to grow a new head (or the rest of its vital organs), and will instead die.

If a worm’s skin dries out, it will die. This happens because the worms’ homes in the soil got flooded, and the worms came to the surface in search of less soggy conditions. Once on the pavement, worms often get disoriented and cannot find their way back to the soil. They then dry up and die when the sun comes out.

But what’s the advantage of suicide? Teri Balser, an associate professor of soil and ecosystem ecology at UW–Madison, says the answer starts with the fact that worms breathe through their skin. “The worms can’t get enough oxygen when the soil is flooded, so they come to the surface to breathe.” Beats drowning.