The movement and excrement of earthworms are very beneficial to improve soil quality, which can maintain the permeability and health of soil. It plays a very important role in agriculture and is regarded as "one of the basic creatures in the world".

Earthworms are also a food source for many higher organisms. Earthworm manure is rich in nutrients and microorganisms such as nitrogen, phosphorus and potassium, and it is the most natural fertilizer.

Because earthworms react to most agriculture and herbicides, we can judge the quality and toxicity of soil by observing earthworms.

Extended data

Earthworms are about 60mm- 120mm long, weighing 0.7-4 g, and the largest is 1.5kg. They are cylindrical and slightly brown, and consist of about 100 knots. The front is a little sharp, the back is a little round, and there is an inconspicuous ring at the front.

The ventral surface is light in color, and there are bristles in the middle of most segments, which play a fixed supporting role and auxiliary movement role when the earthworm crawls.

Earthworms have negative phototaxis, live in moist, loose and fertile soil, and mainly feed on rotten leaves. Most earthworms can eat food equivalent to their own weight every day. It eats soil into the body, absorbs microorganisms, and then discharges indigestible sand. It is generally believed that the life span of earthworms is less than five years, but it is controversial.

Baidu encyclopedia-earthworm