The earthworm is a kind of beneficial worm. It is the food of the animals on the ground. Underground, it fertilizes the soil of field and garden. Earthworms dig burrows which loosen the soil so as to air and water can more easily reach the roots of plants. The burrow also facilitate soil drainage. Earthworms drag dead leaves, grass and petals into their burrows and the decay of those things fertilize the soil. It contribute more excellent surface soil than any animals. According to relevant statistics, within one year, fifty thousand earthworms can produce about eighteen tons of fine soil on one acre of land.
