The lowly earthworm is lowly only because of the place where it lives. It serves a high level function as a tiller of the soil. Agriculture in general, and out lawns and gardens in particular, would be much poorer if worms were not present as improvers of the land.
About 1,600 years ago, the philosopher Aristotle, called earthworms the intestines of the soil this is quite appropriate because they continually burrow through the earth. In the process, they eat and digest the soil to secure food from the organic matter it contains. Under optimal conditions, they will produce their weight in castings every 24 hours. These castings are much richer in minerals than the soil from which they are produced.
In the intestines, ingested soil and organic matter is mixed with ammonia-rich secretions, the worm absorbs he nutrients it needs, and then excretes castings filled with soluble nutrients extracted from the soil. USDA tests comparing earthworm castings to the soil from which they were made show that the castings contained 5 times the available nitrogen, seven times the phosphorus, 11 times the potassium, three times the magnesium and 1.5 times the calcium.
One of the principal benefits of earthworms is the tunnel system they develop. Their main burrows allow water and air to penetrate rapidly into the soil. The roots of plants may follow these tubes as an easy way of growing down through dense soil.
Most earthworms live one to two years. In the soil, they may reach very high numbers. Researchers have found from 190,000 to more than 2 million per acre. With such large numbers in the ground, it is easy to understand an added benefit – the significant contribution to the organic matter content of the soil made by their dead bodies.
There are over 1100 different species of earthworms. Several of the most common types may be familiar to gardeners. The dark red or bluish worms, which become the large,”night crawler” when mature, are of great value in the soil. They are active burrowers which improve aeration and he nutrient content of our garden soil. They can burrow from 2 to 10 feet into the soil. The smaller, grey, garden of field worm generally lives within the top 10 inches of soil. It tolerates less fertile, less organically-rich soil so it is very valuable where soil needs improvement. Its castings are mineral-rich.
In manure and compost, two smaller reddish worms may be found in large numbers. Both are known as “little, red wigglers” or red worms. Both are prolific breeders and rapidly break down organic matter into humus. Humus provides many binding sites for essential plant nutrients such as calcium, iron, and sulfur and stores them in a form readily available to plants.
Encouraging worms in your soil can greatly improve soil structure and productivity. A few guidelines:
*Add plenty of organic material (OM) to your soil for worm feeding.
*Mulch with OM to protect from sudden temperature changes.
*Keep pH from 5-7.
*Avoid chemical fertilizers and pesticides.
If you need suggestions or additional information on any of your gardening questions, call Nancy Olsen at the Bladen County Cooperative Extension at 910-862-4591 or come by the office located at 450 Smith Circle Dr. in Elizabethtown.