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The Permacultivator - Journal of Cool Climate Permaculture
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Worm Farming

Ineke Veerkamp gives an introduction to the subterranean world of worms

Species:-

There are at least 3500 different species of worms in the world.

In Australia there may be more than 500 species, 350 species identified including imported ones, & 300 species of indigenous earthworms.

To identify a worm use only mature specimens as many of the superficial identifying characteristics do not emerge until maturity.

Agricultural worms vs Commercial worms

Agricultural worms; native worms tend to disappearwhen pastures are improved and imported worms ultimately replace them. The reason for their disappearance is not fully understood a popular theory is that the native worms have evolved over millions of years in relatively poor soils and they simply cannot stomach the richer diet in improved soils. So worms usually found in a garden or pasture will most likely be of European in origin.

Commercial worms are worms that thrive in crowded environments, achieve sexual maturity quickly ie a matter of months. Of the worm species found in Australia Lumbricus rubellus (Reds), Eisenia fetida (Tigers) and Perionyx excavatus (Blues) are easily bred in captivity and easily farmed. They are all imported.

Disease

Worms are subject to so few diseases you can say they don’t catch any. Disease - producing bacteria find life very difficult in an earthworm environment because the bacteria fostered in the worms guts and excreted with their castings are benevolent and produced in such overwhelming numbers. Antibiotics are found in the environment created by earthworms. Streptomycin was once thought to be an earthworm secretion but it is the production of soil (fungi like) bacteria named actinmycetes, that seem to be forstered in an environment created by earthworms. Other antibiotics found in soil are Terramycin and Erithromycin.

Most disease producing Bacteria require an oxygen free (anaerobic) environment but the earth worms create a very oxygen rich (aerobic) environment. True worm castings are very low in disease producing bacteria.

Vermicasts

Worms eat half or more of their own weight daily and as they do they will till, aerate and ferilise the soil. The castings produced by worms act as a fertiliser.

This table shows a typical analysis of cattle manure before worm ingestion and after, which clearly shows an increase in availability (ppm= parts per million.)

N

N

K

P

Ca

Mg

ammonium

nitrate

%

%

%

%

Before:

117.1 ppm

8.8 ppm

0.19

0.11

0.35

0.05

After:

141.5 ppm

259.4 ppm

0.41

0.18

0.59

0.08

A 90% dilution of the vermicast resulted in less than a 5% fall in the fertility index, as much because of the work of the bacteria which released the locked up minerals in the soil as the plant-available nutrients already in the vermicast. Tests in France at the Sovadec Ecotechnologie, Montelimar produced the following results;

Test soil was rated a fertility index of 22
A mix of horse and cow manure was rated 24
Vermicast produced from the manure mix was rated 52
A mix of 10 % vermicast and 90% parent soil was rated 48

Anatomy.

The clitellum is a saddle or ring sometimes raised or wider than the body, sometimes not. It denotes sexual maturity.

Contrary to popular belief worms do not mate between species. They can’t because generally the sexual organs of two species don’t correlate so cross fertilisation simply cannot occur. Also differing species are genetically incompatible.

There are no known hybrids or crossbreeds.

The act of reproduction varies considerably between species as does the frequency and the number of young produced. All worms are hermaphrodites (they possess male and female organs).

Reds and Tigers always need two worms to reproduce. Blues can do it alone ie parthenogenesis.

On the anterior of the clitellum are two nerve endings, photoreceptors.

These are extremely sensitive to light. A worm has thousands of nerve endings over the length of the body. These are particullarly sensitive to light, especially ultra violet light, (exposure to which will kill worms) They act as a warning system and send the worm burrowing for cover.

Worms have 3-5 hearts need all to survive.

If cut in half they die. Blues can rebuild themselves and survive but usually end up shorter.

Worms live a long time eg Red kept in isolation for 15 yrs then killed and dissected - no sign of aging found.

Some species live only for a year.

Source: Edwards, C. A. & Neuhauser E.F.,"Potential of Earthworm Composts as Plant Growth Media."

NB Yates garden guide analysis of cow manure figures are totally different to these. Who’s right?

Notes on Vermiculture

Breeding

Food

Building Beds

Watering

Danger

References

J26 Winter 99