Why is the earthworm called the friend of the farmer?

Role in agriculture:

Earthworms are called friends of the farmers due to the following reasons:

• Increase soil fertility- They are detritivores that help in decomposition of fallen leaves. Their excreta called worm casting is rich in nitrogen therefore increasing soil fertility.
• Increasing plant productivity- Earthworms help in making the soil porous as they keep burrowing. This helps in plant respiration and penetration of the roots of the plant into the soil. Earthworms also help in nutrient cycling thus making important nutrients like potassium available to the plant.
• Vermicomposting- Earthworms are used to convert organic matter into fertiliser thus helping in the process of organic farming.