Earthworms and why they are so important

The wonder of Earthworms!

You have seen them when you dig in the soil, and my dad used those little wriggles as bait on fishing weekends.  When you see an earthworm, you know you are on the right track with your soil. Why are earthworms so good and why do we need them?

Earthworms are more than just fish bait.

Earthworms are the main contributors to enriching and improving soil for plants, animals and even humans. Earthworms create tunnels in the soil by burrowing, which aerates the soil to allow air, water and nutrients to reach deep within the soil. Earthworms eat the soil which has organic matter such as dried leaves and grass clippings. Plants cannot use this organic matter directly.  After organic matter is digested, the earthworm releases waste from their bodies called castings. These castings contain many nutrients that the plant can use.

Let’s get scientific for a few seconds

The digestive system is partitioned into many regions, each with a certain function. The digestive system consists of the pharynx, the esophagus, the crop, the intestine and the gizzard. Food such as soil enters the earthworm’s mouth where it is swallowed by the pharynx.

The soil passes through the esophagus, which has calciferous glands that release calcium carbonate to rid the earthworm’s body of excess calcium. After it passes through the esophagus, the food moves into the crop where it is stored and then eventually moves into the gizzard. The gizzard uses stones that the earthworm eats to grind the food completely.

The food moves into the intestines as gland cells in the intestine release fluids to aid in the digestive process. The intestinal wall contains blood vessels where the digested food is absorbed and transported to the rest of the body.

Worms are hermaphrodites. Each worm has both male and female organs. Worms mate by joining their clitella (swollen area near the head of a mature worm) and exchanging sperm. Then each worm forms an egg capsule in its clitellum.

As Darwin, who spent 39 years researching the Earthworm wrote ‘There are few animals which have played so important a part in the history of the world than the earthworm. They are a natural way to maintain soil structure and fertility as they aerate the soil, improve drainage, and bring nutrients to the surface. These actions help support the ecosystem services that soil provides. ‘

Earthworms tunnel deeply into the soil and bring subsoil closer to the surface mixing it with the topsoil. Slime, a secretion of earthworms, contains nitrogen. Nitrogen is an important nutrient for plants. The sticky slime helps to hold clusters of soil particles together in formations called aggregates.

You know you are dealing with good soil when you find Earthworms.  Earthworms live where there is food, moisture, oxygen, and a favorable temperature.  They will die if they dry out.

Fun Fact: The longest earthworm ever found was a specimen of the African giant earthworm, Microchaetus rappi, measuring 6.7 meters long and 2cm in diameter. It was discovered in 1967 on a road in South Africa between Alice and King William’s Town.  Not to worry,  you are not likely that you will find this beast in your back garden!  The common earthworm is typically 20–25 cm long.

Next time you see these workers in the garden smile, and cover them up again. Although Earthworms have the ability to replace or replicate lost segments to a small degree, when chopped in half, usually both halves will die.

Happy Gardening Friends

Tash & Family