The information I will give you today is derived from my own personal observations, observations of Jim Kinsella, several articles, and two books: "The Biology of Earthworms" by C.A. Edwards and J.R. Lofty and "Earthworms" by K.E. Lee.

1. Value of earthworms: If you had 1 nightcrawler/sq. ft. at $1/dozen, then 1 acre has retail value of $3630.

2. When ecological niches are filled there will be 3 to 5 species present.

4. Let's put 1 ton of earthworms in perspective (see figure 2).

A. 1 ton earthworm would be 20 feet long and 16 inches wide. Let's say it has vertical burrows 3 times its length and it eats its weight in soil 100 days out of the year.

Casts are evenly spread on surface: these annual deposits of 100 tons would be

2/3 " deep.

Burrows would be 60 feet deep and about 25 per acre.

Another way of looking at all those burrows is to put them in terms of a 6-inch tile. One million earthworm burrows would have the equivalent space of 4000 feet of a 6-inch tile. On a square acre, there would be a tile running the length of the field every 20 feet. With the Illinois price of $1.20 per foot installed, those burrows are worth $4800 per acre.

B. Earthworm Benefits

1. Improve water infiltration rates: This is aptly demonstrated by the work of Dr. Bill Edwards at Coshocton, Ohio. On a sloping field with no-till practices there were 155 earthworm holes per square yard and an average runoff of .08 inches per year, This compares to a tilled field with 6 holes per square yard and 4.9inches runoff per year. Th average rainfall for this area is 39.4 inches. Jim Kinsella of Lexington, Illinois will drive the top part of a metal barrel into his earthworm rich soils, pour in about five gallons of water, and in a matter of minutes, it is all gone. In similar soils on neighboring farms, it takes hours for the water to disappear. There is a belief that earthworms could just about eliminate soil erosion caused by water runoff.

 

2. Improve soil aeration: All those earthworm burrows described above are macropores. A macropore is an air space, which will not hold water against gravity. Ideally your soils should have about 25% air spaces or macropores, 25% water spaces or micropores, and50% solids. Loss of macropores results in denser soils and soil compaction. Rooting depth is directly related to the amount and rate of diffusion of oxygen in the soil. Also, if three feet of soil profile had 25% macropores, then that soil should be able to take a nine-inch rain without runoff.

3. Create fertile root channels: The mucous linings of the abandoned burrows or the subsurface castings are excellent sources of nutrients and ideal rooting environments. Roots can grow fast and go deep in earthworm burrows.

4. Counteract leaching: For those earthworms that have long vertical burrows and cast on t e surface, their burrowing can bring up nutrients that have leached beyond the root zone. Or looking at it another way, the earthworm burrows allow roots to go down deeper and "chase" or intercept the leached nutrients.

5. Remove litter from soil surface: Mainly the action of surface feeders and the beginning of the humus formation. No-tillers with residue accumulation problems need to encourage more earthworm activity.

6. Help compost residues and waste products: The activity of the earthworm gut is like a miniature composting tube that mixes, conditions, and inoculates the residues. Moisture, pH, and microbial populations are favorably maintained for a synergistic relationship.

7. Bring up minerals: Again, this is the action of earthworms like the nightcrawlers, which have long vertical burrows. Their deep burrowing and subsequent casting on the surface can bring up minerals that may be in short supply in the surface layers. One ton of earthworms per acre should be able to thoroughly mix the top two million pounds of soil every ten years plus additions from the subsoil. You can sell the plow.

8. Make plant nutrients more available: Analysis of earthworm casts shows much more available phosphorus and potassium than surrounding soil. One of the best soil tests I have seen in thirteen years of soil sampling was from a field which had not been fertilized in five years, but had a very active earthworm population. I believe we can build soil fertility faster and cheaper with earthworms than with commercial fertilizers. This would be a holistic biochemical approach versus a chemistry approach. Those one million earthworm should also be able to annually supply your maintenance fertilizer. Now that's sustainability.

9. Chelate micronutrients: One study showed molybdenum became available to alfalfa only in the presence of earthworms. Soil testing indicated plenty of molybdenum, but alfalfa roots were not modulating well, a process, which is enhanced by molybdenum. Introducing earthworms to the field corrected the problem.

10. Stimulate microbial populations: Free-living nitrogen fixing bacteria were more numerous around the sides of the earthworm burrows. Researchers have found increased numbers of bacteria and Actinomycetes in earthworm casts. The Actinomycetes are credited with giving soil that "earthy" smell, and can be considered as indicators of a healthy soil. With the loss of the earthworms and subsequent reduction Actinomycetes, we have a whole generation of young farmers who do not know the intoxicating smell of a really good soil.

11. Plant growth stimulants produced in casts: Auxins have been found in earthworm casts. These plant growth hormones help roots elongate and grow. So the earthworm burrow not only offers a terrific environment for the plant root, but the casting in the burrow or on the sidewalls stimulate the roots to grow faster. You have to see it to believe it. Jim Kinsella showed me soybean roots growing down earthworm burrows and had nodules at least 12 inches deep. Most farmers in Illinois are lucky to see Rhizobium nodules at 4 inches.

12. Neutralize soil pH: Cast analysis shows that soil comes out the back end of the earthworm closer to a neutral pH (7) than what goes in the front end. So if the soil is below a pH of 7, the earthworm cast will have a slightly higher pH. If the soil is above a pH of 7, the casts will have a slightly lower pH. This all comes about through the action of the calciferous gland in the earthworm gut and the buffering action of carbonic acid. I believe we can eliminate the need for limestone if we maintain good aerobic conditions and healthy earthworm populations.

13. Improve soil structure: This may take awhile, but the binding properties of the earthworm mucous and the cast material will slowing create or maintain good soil structure. Soil peds or aggregates the size of small soybeans will begin to appear. Researchers claim differences can be seen in five years. I have been able to speed up the process by combining cover crops with earthworm activity. Noticeable chan s can be seen in two years, especially when using hairy vetch.

14. Increase moisture absorption: Casts absorb water faster than soil. This reminds me of that paper towel commercial.

15. Increase moisture available to plants: Studies showed that soil with earthworms held more water and had more water available to plants than soil without earthworm. This might make the difference whether your plants die in a drought or hang on until the next rain. My research farmers who are fighting their compaction and encouraging their earthworms are starting to see higher yields than those of their neighbors. After all, your plants are about 70% water, and anything you can do to enhance moisture retention and uptake will benefit those plants.

16. Increase the water stability of soil: Earthworm casts can take a "direct hit" by a raindrop and maintain their shape.

These stable aggregates are loss prone to the soil dislodging action of rain and possible soil erosion with the runoff.

17. May eat and destroy nematodes: Soil with earthworms had less plant parasitic nematodes than soil without earthworms. The actual eating of the nematodes may be accidental and the reduction may be more of a result of the increased microbial activity in the earthworm gut and the casts. In Illinois, I have observed a definite correlation with the lack of earthworms and the increase incidence of lesion nematode problems. The evidence is a little weak, but the damage of soybean cyst nematodes may be reduced by earthworm activity, or more likely by the combined action of rye and earthworms.

5. Why No Earthworms?

1. Food: There is a direct correlation between earthworm numbers and the amount of food. Surface feeding earthworms don't know that the residues have been plowed under and so they go hungry. Some residues have too wide of a carbon to nitrogen ratio to be good food. Earthworms are poor assimilators of energy, so they must eat a lot to gain a little. Lack of protein from a legume or animal manure or from slow microbial degradation of residues can discourage earthworm.

2. Shelter: Like most animals, earthworms need shelter from the extremes in the environment and shelter from enemies, Sudden and penetrating frosts can be very deadly for active earthworms. Winter cover crops not only buffer the soil from quick freezes, but also protect the earthworms from some of their predators. Some, if not all, of the winter cover crops will also be a food source, I have found that earthworms do very well under hairy vetch, and conversely, hairy vetch does very well with earthworms.

2. Tillage: Destruction of food sources and of burrows can be harmful to earthworm populations. Very few earthworm species can survive the plow and winter fallow. Tillage also destroys structure. Lack of structure leads to soil compaction. Soils may be physically inhabitable to earthworms. The soil may be so tight, that the earthworm can not borrow down or through it. Hard pans or plow soles may affect earthworm summer drought survival.
3. Anhydrous ammonia: Besides the initial toxic effect of the gas, the dissolving effect on the soil binding compounds may lead to weak soil structure. This weak soil structure is more prone to compaction from tillage and/or wheel traffic.
4. Insecticides: In the past some very toxic and persistent insecticides were used which were very deadly to earthworms. Some fields may only now after twenty years be reaching a nontoxic level of aldrin or heptachlor. Today's insecticides although less persistent are still toxic to earthworms. The combination of insecticide use, tillage, and winter fallow are keeping the earthworms out of many fields.

1. Taxonomy and ecology: It is very important that researchers learn the identity of the different earthworm species so that research results can be compared and communicated. Is the red worm of North Dakota the same red worm of Illinois? How many different night crawlers are there? Will the brown worm of Illinois be able to survive the drier and colder climates of the northern states? Which are the best colonizing earthworms?

Which are the best earthworms for eating crop residues? There are at least seven different species f earthworms around Springfield: small pink, small red, small gray, medium red, large brown, large pink, and large reddish brown.

2. Management of livestock: To take advantage of all those good benefits listed above, the farmer will need to know how to insure the growth and survival of his earthworm herd. These management practices will vary from state to state and from crop to crop. What farming practices are earthworm friendly and what winter cover crops will be good food and shelter? Should you be treating the residues? What times of year are the earthworms most active and when are they most vulnerable to injury from farming practices? No-till favors earthworms if you are not dealing with a compaction problem. Legumes in the rotation or as winter cover crops are good. Earthworms are most active around a soil temperature of 50 degrees Fahrenheit. I believe that continuous cropping similar to nature 's grasslands or perennial forests are beneficial for stable earthworm populations. Non-rotational summer crops can be supplemented with an appropriate winter cover crop. Or winter crops can be supplemented with an appropriate summer cover crop.

3. Introductions and succession: If fields are devoid of earthworms, transplanting adult worms or cocoons may be successful if the conditions are favorable for earthworm survival and growth and reproduction. Bill Kreitzer of Advanced Biotechnology, Inc. of Gibson City, Illinois, is presently researching encapsulating earthworm cocoons and planting them with the planter along with the seed. As this technology develops, different earthworms will be available for different uses. Can you imagine sitting down and thumbing through a catalog of earthworms? Let's say that after you do an earthworm analysis, you find that you are missing earthworms in one of the ecological niches of the soil profile. You will be able to look through this catalog and choose the best earthworm for that niche. Or let's say that you are just getting started, and you need the best colonizing earthworm for your area and crops. Bingo! The catalog offers you two or three different earthworms for that purpose. After making your choice, you dial an 800 number and place an order. Depending on the species and the number requested your earthworms would be shipped ready for planting within the month or within the year. You will work closely with a biologist who will help you insure the safety and survival of your new investment. Some of this may take one or two years of field preparation, but the benefits will be well worth it. I hope some of you can quickly see that many regional breeding farms with controlled conditions will be needed, as well as a skilled labor force of earthworm herdsmen.

In closing, I hope after seeing all of this, that you will view the soil and its' management as a home for your friends, the earthworms. Please remember that from all the literature and personal experiences to date, the earthworms are always working to make the soil better, not only for their survival and reproduction, but also for the health and survival of their food source, your crops. Indeed, earthworms are the true stewards of the soil.

original proceedings.