·PE BLACKM AS. o· p 631.4(94) I

AS:PE BLACKM p 631.4(94) Di

DISCOVERING soils; no.S.

Earthworms for gardeners and fishermen. Rev.ed. [Adelaide], CSIRO Division of Soils, 1986 ( repr. 1989).

31 p. Text by Kevin Handreck, Ken Lee.

1. T,ITLE 2. EARTHWORMS LH /EC [ 91 / 2852] ISBN O-643-O4237-7

ZM4-5

0 BLACK A OU TA r . ~ c::: ..,

Earthworms for Gardeners and Fishermen

Discovering Soils No. 5

• CS I RO AUSTRALIA

DIVISION OF SOILS

Discovering Soils Booklets : Soils : An Outline of Their Properties and Management Soil - Australia's Greatest Resource Composting : Making Soil Improver from Rubbish What's Wrong With My Soil? Earthworms for Gardeners and Fishermen Food for Plants Organic Matter and Soils When Should I Water? Potting Mixes: and the Care of Plants Growing in Them

National Library of Australia Cataloguing-in-Publication Entry Handreck, Kevin Arthur, 1938- and Lee, Kenneth E., 1927-

Earthworms - for gardeners and fishermen. (Discovering soils). Bibliography.

ISBN O 643 04237 7

1. Earthworms. I. Title. (Series)

595.146

©CSIRO 1978 Completely revised, 1986 Reprinted 1988 Reprinted 1989

Earthworm Species of Australia

Effects of Earthworms on Soils 2

Likes and Dislikes 4

Increasing Earthworm Numbers 6

Cultural Methods 9

Vermicompost and Worm Castings 16

Earthworm Biology 21

Identifying Earthworms 27

Further Reading 30

CONVERSION TABLE

1 kg/m2 = 1 kilogram per square metre= 3.3 ounces per square foot

1 cm = 1 centimetre= 10 millimetres= 0.4 inches

11 = 1 litre= 1.76 pints

Earthworms for Gardeners and Fishermen

Gardening and fishing might at first sight appear to have little in common. Both take time for success and so tend to be mutually exclusive activities. But the humble earthworm provides one point of contact. Gardeners like earthworms because of their beneficial effects on soil: fishermen like earthworms because some fish like them. In different ways the earthworm is involved in two pleasurable human activities that also increase food production.

This booklet is about earthworms - their habits, likes and dislikes - and about ways of producing more of them.

At the start of European settlement the forests and grass- lands of Australia were inhabited by perhaps several hundred native species of earthworms. Since then, clearing and ploughing have eliminated these worms from very large areas. In the wetter coastal fringe their place has been taken by earthworms introduced from Europe along with potted plants. Now the native worms are largely restricted to uncleared bushland and forest areas.

The earthworms we dig up from our gardens and pastures in southern Australia are mostly of the introduced European kinds, and are more likely than not to belong to one of the following species: Aporrectodea caliginosa, A. longa, A. rosea, Lumbricus rube/lus, Eisenia fetida (tiger worm) and Enchytraeus albidus (white worm). The first four species are the most common. Tiger worms are generally restricted to compost heaps, animal manure and areas where there is a lot

2

of leaf mould. White worms are found mainly in wet areas such as along the edges of lakes and marshes. White worms may also be found in abundance in earthworm cultures which have become too acid.

Little is known about the earthworms of gardens and farms in tropical Australia. Species which appear to be common include Pontoscolex corethrurus, Ocnerodrilus occidentalis and several species of the 'Pheretima' group of genera. These are species that have originated from central America, Africa and southeast Asia and have been spread by man throughout the tropical regions of the world.

The key on pages 27-29 will help you to identify the most common earthworms, but the listing is far from complete.

Earthworms are good for soils. They: * Break up organic materials * Mix these organic materials into the soil * Break up root mats in pastures and thick layers of leaf litter * Increase microbial activity in the soil * Increase the availability to plants of nutrients in soils and

organic matter * Improve the crumb structure of soils, and so * Increase the amount of water that can be held in soils * Allow better penetration of plant roots, oxygen and water

into soils * Increase crop and pasture yields * Help reclaim land (including mine dumps) by increasing

soil fertility. Earthworms eat large amounts of organic materials. Some

species pull leaves or parts of leaves into their burrows before

3

eating, others feed in surface litter, while others get their organic matter during passage through the soil. An individual can eat as much as 40 g (dry matter) per year. This works out at 80 tonnes per hectare per year for a typical population of 200 worms per square metre! Actual field figures are probably much less than this in Australia because of long dry periods when earthworms are inactive.

Earthworms eat to live, but an important side benefit for soils and plants is that the organic materials are broken up and mixed with the soil. In the process, the nutrients in them become much more readily available to soil micro-organisms and to plants. The increased microbial activity further aids organic matter decomposition and hence nutrient availability to plants. For example, studies in Adelaide have shown that about 6% of the nitrogen in organic matter previously unavailable to plants becomes available after passing through earthworms. Calcium, magnesium, potassium, phosphorus and molybdenum (at least) are all many times more readily available in worm casts than in the surrounding soil, and casts are also of a more nearly neutral pH than the soil. Increased availability of nutrients is one reason why plant growth is generally increased by earthworms.

Earthworms eat large quantities of soil as well as organic materials. Each day they eat about half their own weight of soil. For typical population densities in southern Australian pastures, this works out at 3.6 kg/m2 per year or an amount of soil equal to that in the top 15 cm every 60 years. Species that excrete their faeces as casts on the surface of the soil have been shown to bury the original surface to a depth of 18 cm in 100 years in Britain. The common earthworms of Australia tend to excrete most of their casts underground and so only add a layer about 1.8 cm thick in 100 years.

The gastronomic habits of earthworms also increase plant growth through improvements to the physical properties of soils. Earthworm burrows provide channels for root, water and air penetration deep into soils and so increase the volume of soil from which plant roots can extract nutrients and water. The crumbs or aggregates of soil formed from casts are usually more stable than the bulk of the soil. They pack together more loosely and so allow easier penetration of roots, water and air. Soils with a high proportion of stable aggregates are less liable to erosion or compaction.

Soils with earthworms are generally able to hold more water without getting waterlogged than soils with no earthworms. The water is held in the aggregates while air can still move through the soil between the aggregates. In New Zealand some soils have a 20 per cent greater water holding capacity since the introduction of European earthworms. This means that more water is available for plant growth.

For completeness, mention should also be made of two

4

[7" I\

situations in which earthworms are not welcome. Those that excrete casts on the soil surface are a nuisance in bowling and golf greens and ornamental lawns. Earthworms readily eat the organic components of potting mixes. This eating causes more rapid decomposition of the mix than would otherwise be the case, leading to slumping in the pot and to a need for early repotting. The channels produced by the earthworms are of little advantage to the plants if the mix is already open enough for excellent drainage. Apart from these minor problems, the evidence is overwhelmingly in favour of the beneficial effects of earthworms on soils and plants.

},_:_,:.::.:_:_:'.;. :_: ,::-.·:, ·.'-.·:

Earthworms, like all other living things, need food - lots of it and of suitable quality - if they are to g row and multiply. Leaves, lawn clippings, weeds, vegetable scraps, compost and animal manures really turn them on. Some of them feed on surface litter at night but most species present in Australia prefer to eat it as they chomp their way through the soil itself. This predominance of below-surface feeders seems to be due mainly to our climate. In much of Australia our surface soils dry out for several months each year and they can get very hot. Soil temperatures above 25°C usually prove fatal for the earthworms of temperate regions and death is more rapid the drier the environment. To avoid getting roasted, earthworms go deep into the soil - up to60 cm-and rest untit conditions are more favourable near the surface. Even in garden soils kept moist throughout the summer, worms tend to remain well down in the soil tn the hottest part of the year. Organic mulches help keep the soil cool and so help extend earthworm activity into the hotter months of the year. Some earthworms of tropical areas can survive for extended periods at temperatures up to 30°C.

Earthworms don t like being chopped up by spades, impaled by forks, smeared flat by plough shears or gobbled up by birds. As well as these direct effects of cultivation, if ploughing forms a hard pan in the soil, earthworms may be trapped above it, and therefore die through dessication during summer. Cultivation is definitely not good for earthworms. Recent studies have shown that earthworm populations in cropped fields sown by direct drilling methods are much larger than in those prepared using several cultivations.

In soils supporting alternate crops and pastures, earthworm numbers are highest at the end of the pasture phase and

5

..

lowest at the end of the cropping phase. In gardens, some cultivation is necessary, but if earthworm numbers are high the few lost won't matter much.

Earthworms prefer to live in a light, loamy soil so the structure of heavy clay soils needs to be modified if large numbers of earthworms are wanted. This can be done in part by adding coarse sand, but large quantities of organic materials should also be used. Adding gypsum to clay soils can help improve structure and can prevent the formation of surface crusts.

Each species of earthworm has its preferred range of soil pH. The further the pH goes away from this range, the smaller is the population of the particular species. Earthworms are absent from soils with a pH of less than about 3.5 or more than about 9.2. A few species (including Dendrodrilus rubidus) are present in the range 3.5-4.5.

Most species are tolerant of pH values within the range 4.5 to about 8, with the greatest number of species being present in soils with pH values in the range 5-7.4. A few species are not found in soils with pH values of less than 6. If your soil has a pH of less than about 5.5 and you want large numbers of earthworms, add wood ash, lime or dolomite to increase pH to a little more than 6.

Earthworms don't like being sprinkled with fertilizers (or indeed with any dry material). They squirm and wriggle in a frantic attempt to rid their skins of adhering particles, which, if left on would in some cases burn holes in them and dehydrate them. But often we do have to add fertilizers to our soils. The fewest worms are damaged by sprinkling the fertilizer on the surface of the soil and watering it in some time before digging. The long-term effect of fertilizers on earthworms varies with fertilizer type and soil. If fertilizer application greatly acidifies the soil, then earthworm populations will decline because of this acidity. Ammonium sulphate, nitrate and phosphate, and

Channels produced by earthworms ,n uncultivated wheatland soil

6

The snail and slug killers metaldehyde and methiocarb are not harmful to earthworms at the usual rates of application. Metaldehyde has a very much better safety margin than methiocarb.

urea, are the fertilizers most likely to acidify a soil. Long-term use of superphosphate will acidify a soil if limestone or dolomite is not also applied. But if application of a fertilizer increases the amount of plant growth, and hence increases the return of organic matter to the soil, and soil pH is still in the acceptable range, then that application will increase earthworm numbers.

Research has shown that many sprays reduce earthworm numbers. Particularly lethal are the fumigants and nematicides Chloropicrin, Metham, Methyl bromide, and D.D. and the ant and termite killer Chlordane. Many carbamates (Aldicarb, Carbary!, Dithiocarbamate, Methomyl, Oxamyl, Propoxur) are highly toxic as are Benomyl (Benlate) and Thiabendazole. Heavy applications of Aldrin, Dieldrin, TCA and atrazine reduce numbers. DDT and Lindane applied at the rates recommended for controlling pests have little effect, although higher rates of application are lethal. Arsenic compounds and high levels of copper salts seriously reduce earthworm populations. Most herbicides have little effect on earthworms when applied as recommended.

The simple message here is to go easy on chemical sprays if you want plenty of earthworms.

Pamper them - provide them with the right temperature and moisture and plenty of high quality food - and earthworms will do the rest themselves. Depending on species and conditions they may even double their collective weight every month.

Garden Soils Garden soils in Australia soon come to acquire a population

of earthworms. In southern Australia these earthworms will bi:;, of European extraction, but in the tropics they will most likely be one or several of the earthworms which inhabit the soils of most other tropical countries. These earthworms may simply move in from next door or they may be brought in with plants or soil. Several species may come in, but eventually those species which are best adapted to the particular soi, and vegetation conditions of the site will come to be present in greatest numbers.

If you find that you do not have earthworms in your garden, the best source of some is a nearby garden. The similar soil and climate of a nearby garden should ensure that the species

7

you introduce to your garden will thrive there. Such earthworms are more likely to thrive than earthworms cultured on animal manure in some distant earthworm farm. Collect several hundred if possible. Place them in groups of about 50 in holes scattered around the garden. Leave some food (chopped kit_chen scraps, imma~ure compost, etc.) in each hole. By leaving the earthworms 1n groups, you maximise the chance of them breeding rapidly. As their numbers increase, they will spread to other parts of the garden.

The total number which can be supported by your garden depends directly on the amount of food available, assuming that environmental conditions are otherwise satisfactory. There is no point in introducing large numbers of earthworms if there is no food for them and you are not prepared to provide more. If you want the advantages that a large population of earthworms bring to a garden then you must look after them. * Mulch your soil, especially in summer in southern Australia

and in the dry season in the north. This extends the portion of the year during which the earthworms are active.

* Provide them with plenty of food. Allow plant litter to remain on the soil surface. Bury kitchen scraps in holes 20-30 cm deep scattered throughout the garden. If you want an initial rapid build-up in a population, you could provide extra food via food pellets such as those fed to poultry, horses or domestic animals.

* Keep the soil moist at all times. Be careful not to over-water, so that the soil becomes saturated and earthworm burrows are flooded.

* Don't use pesticides which would harm them.

,

Equipment used to transfer turi (and earthworms) from one pasture to another in north-eastern Tasmania

8 Field Soils

The remarks above for garden soils apply equally to field soils.

An alternative method of introducing earthworms into pasture soils is via squares of turf from a pasture containing many earthworms. These squares can be about 30 by 30 cm by 10 cm deep and each should contain at least 10 worms. Place these squares upside-down on the surface of the pasture being inoculated. The earthworms will soon move down into the soil below. The rate of spread from these inoculation sites will depend on environmental conditions and food supply. The more vigorous the pasture, the greater will be the rate of return of plant debris and animal dung to the soil and so the greater will be the rate of increase in earthworm numbers. Under fair conditions the earthworms will spread outwards from inoculation sites at a rate of about a metre every 18 months. Thus inoculation sites spaced 10 metres apart could lead to complete occupation in 6-7 years. For success, you should apply lime to very acid soils (pH below about 5.5).

There is no point in attempting to introduce tiger or red compost worms to garden and field soils, as conditions there are rarely suited to them. These species might survive and thrive in very rich and constantly moist garden soil, but not in harsher conditions.

Earthwonn Cultures Before setting up an earthworm culture, you must decide on

your aims in setting it up. You will probably be wanting to achieve one or more of the following. * Produce worms for bait for freshwater fishing. * Convert kitchen scraps and/or garden wastes into

vermicompost for use on the garden or in potting mixes. Follow the guidelines which start on the next page.

* Ouicklyproduce large numbers of worms for transfer into a soil. It is doubtful if there is much sense in doing this for most situations. Those worms which are best suited to soil conditions tend to grow fairly slowly in rich organic cultures, or they do not tolerate these cultures at all. It is usually preferable to use the techniques outlined above for garden and field soils.

* Produce earthworms for use as food for other animals. In recent years there have been a number of schemes for using worms grown on waste organic materials as a source of protein in feedstuffs for fish or livestock. At the prices normally obtained for cultured earthworms sold to fishermen, it would be cheaper to feed top quality steak to the fish and livestock. Even at the prices charged for bulk supplies of earthworms, it would be only in situations where

9

the product can be sold at an exceptionally high price that it would be economically sound to attempt to use earthworms commercially in this way. In domestic or other situations where economics are not

relevant, there is no reason why I ive earthworms or earthworm meal from palatable species could not be used as part of the food offered to fish or other animals. Just make sure that the worms are not fed on materials likely to contain toxins such as copper, lead, cadmium, zinc or arsenic, as these can accumulate in their bodies. Therefore avoid organic materials of unknown origin, pig manure and sewage sludge.

Setting Up You have to decide on size and type of containers, site, type

of earthworm to use, bedding material and food.

Environmentally sensible disposal of kitchen scraps

Two commercial Australian earthworm farms

10

Basic backyard verrnicornpostmp

Containers Match container size to the size of your proposed operation.

The smallest practical containers are the foam cartons used for transport of fresh fruit and vegetables. They can be obtained cheaply from your local greengrocer. Other small containers can be made from plastic garbage bins or wooden boxes. They should be about 30 cm deep. If your main purpose is to dispose of kitchen scraps, allow about 0.15 square metres of surface per person in the household. Do not use metal containers. There will be enough copper dissolved from copper containers or zinc from galvanised containers to give concentrations in the finished vermicompost that could be toxic to plants.

For larger operations it is best to construct raised beds about 1 metre wide and 30 cm deep. These may be placed directly on the soil, but removal of vermicompost will be easier if they are placed on concrete. Drainage holes must be provided if the base is concrete, and the beds receive rain. The holes can be every metre or so in the bottom of the walls. Under cover, you may not need drainage holes if you manage water applications carefully.

Site A small culture bed can be kept in the kitchen or back porch.

As long as you maintain the culture properly, there should be no objectionable smell. Otherwise, the culture can be kept anywhere outside where it is protected from direct sun, from frosts and preferably from rain. Direct sun could increase bed temperature in summer to above that tolerated by the worms. Use shade cloth if natural shade is not available. Freezing temperatures will kill the worms and low temperatures (less than 5°C for temperate species and perhaps 15°C for tropical species) will seriously slow their rate of growth. Rain may make the bed too wet - leading to anaerobic conditions, foul odours, perhaps death of the worms, and loss of nutrients through leaching. Small beds can have individual covers, but larger operations are best conducted under cover.

Type of Earthwonn • If your sole purpose is to produce vermicompost, the

earthworms used must be capable of growing fast and breeding prolifically in a rich organic environment. In Southern Australia, that means that you choose Eisenia fetida. Under ideal conditions, 8 of these can increase to about 1500 in 6 months. You could also use Lumbricus rubellus, but its rate of working is not as high as that of E. fetida. In the tropics you will try to get Pontoscolex corethrunus or perhaps a 'Pheretima' that is common in gardens in your neighbourhood.

11

* If you want bait for fishing you should select according to the following information. You should choose those worms which are especially

suited to the fish you want to catch. They should be large, lively for some time on the hook, and palatable to fish. The tiger worm does not satisfy the last two criteria. Studies have shown that rainbow trout thrive on Lumbricus terrestris and Aporrectodea longa but Eisenia fetida was unpalatable. E. fetida is k nown to be unpalatable to the European eel and to Tilapia. In trials with salmon, fishmeal feeds containing more than 20% E. eugeniae, E. fetida and Dendrodrilus subrubicundus inhibited feeding. L. terrestris (not common in Australia) and A longa were eaten voraciously. The species you choose will depend on the climate of your area. In southern Australia you would do well to use Lumbricus rubellus.

Unfortunately, those earthworms which are most palatable to fish grow more slowly than those recommended for producing vermicompost. * Worms for feeding to fish should be chosen on the basis of

their palatability to the species of fish you intend to feed. Use the information above or carry out your own preference trials.

* Worms for making into meal for livestock could be chosen from those that grow most rapidly.

Don't introduce earthworms into composting materials until they have cooled.

Bedding Materials It is customary to start a culture by providing some sort of

bedding material. This material must be porous enough to allow free entry of oxygen and escape of waste gases. The best materials for vermicompost production using tiger worms are cow, horse and sheep manures. The last must be leached first, otherwise it can be too saline for the worms. If these materials are not available you can use peatmoss, shredded paper, a straw/grass clippings mixture, leaf mould, or a mixture of them. Bedding must be moistened until it is just possible to squeeze a few drops of water from a handful. The bed can be a little wetter in the summer but should be on the dry side in winter.

Bedding for the earthworms of southern gardens can be as above, but many of the species commonly found in garden and field soils do not like such a rich organic mixture. For them, start the bed with a 5 cm layer of loamy soil, then 10 cm of partly made (immature) compost, leaf mould or well rotted animal manure and finally another 5 cm soil. Such a bed should be kept rather drier than the one described for vermicompost making.

12

Material

Blood Hoof-and-horn Meat. fish meals Cottonseed meal Manures.

cattle sheep pig chicken

Chicken litter Lawn clippings Weeds Hay Seaweed Layers pellets Kitchen scraps Bread Coffee grounds Egg shells Citrus peel Leaves

legume broad leaf pine eucaiypt

Straw Paper cardboard Sawdust

Nitrogen content (% 1n dry) {approx 1

12 12

5-10 7

2-3 3-4 3-4 4-6 3-4

2 2

1.8·3 1 5

1.3-2.7 1.5 3

1 4 2

1 2 08

2 1.2-1.5

0.7 0 5-0.8 0 4-0 6

0.2 0.1

Adding the Worms You can start a culture with just one pair of worms, but it will

then be a long time before the culture builds up to full production. It is better to add about 50 worms per litre of bedding. This works out at roughly 500 per foam box or 2000 per square metre of larger beds. In boxes, the worms should all be added at one spot along with a supply of food. Scatter groups of worms along the full length of larger beds. Bury the food and then place the worms on the surface above it. They will soon wriggle into the bed to escape from the light. Any that don't disappear can be assumed to be dead or ill and should be removed. The beds should then be covered to exclude light and to reduce evaporation of water. Hessian is the best covering material, but weed control matting is quite good. Black plastic film can be used but it must be loose-fitting so that air is not excluded from the beds.

Food Almost any dead organic matter can be used as food for

worms in culture beds, so long as it contains at least 1% nitrogen. That means that you can use almost everything except sawdust, twigs, bark, paper, cardboard and eucalypt leaves (but the fallen leaves of most exotic trees contain more than 1% nitrogen). You can use these other materials if they are accompanied by materials with higher nitrogen contents. The leaf litter of leguminous trees and shrubs such as acacias and grevilleas contains about 2% nitrogen, so a mixture of it and eucalypt leaves is satisfactory.

The technique of providing food depends on the size of the bed and on your aim. If you want to produce vermicompost, you will continue to add food to the bed until there is enough vermicompost to harvest. You then stop adding food so that the worms are forced to work over the bed materials until most of it is pure castings. Inevitably, this means that the worms run short of food; their rate of growth and breeding slow down.

But if your aim is to produce large fat worms, then you will make sure that they always have plenty of fresh food of high quality. That means regular feeding with kitchen scraps, poultry pellets and the like. When you harvest such beds, you will have a vermicompost which still contains uneaten food and which has not been worked over as much as a more 'exhausted' bed.

Earthworms need protein, but they also need some cellulose. Manures from grass-fed animals and partly composted garden wastes contain both as well as a full rar.ge of other nutrients, so they are excellent food for earthworms. The bacteria which are feeding on these materials are a particularly good food for earthworms. But earthworms can get little nutrition from mature, humified compost and leaf

13

mould. Such materials are similar in composition to their castings.

A small amount of grit in the bed helps earthworms grind their food in their gizzards. Most manures and garden weeds will contain some grit. Ground limestone and crushed egg shells added to raise pH will often provide enough grit, but otherwise add a few percent soil when using other 'cleaner' food.

Manures from grain-fed animals will usually be too rich in soluble nutrients to be used without leaching or mixing with other materials of lower salinity. Manure from pigs fed a ration to which copper salts have been added - and that is most pigs - should make up no more than about a quarter of the total material added to a culture bed. The copper may be present in high enough concentrations to harm the earthworms; it can also damage plants to which the vermicompost is applied. There will probably be little harm done to plants in garden soils when the vermicompost is used at normal rates, but it may harm plants in soil-less potting mixes. Such harm is especially likely if the mix becomes moderately acid.

. ::.·-.··.

Learrunq young

" Animal dung, lawn clippings, leaves and other bulk materials are usually scattered onto the surface of the bed under the covering material. Kitchen scraps are best buried in spots throughout the bed. Large pieces such as cabbage leaves and the bases of cauliflowers must first be chopped into small pieces. Citrus peels are quite acid. They should not make up more than a small proportion of the food added at any one time. They should always be accompanied by a sprinkling of agricultural limestone, dolomite or wood ash. Meat scraps should be mixed with sawdust or other plant material before adding.

Earthworms have been shown to grow well on a mixture of wood fibre (such as shredded paper) and complete garden

14

fertilizer, but the culture bed is not as easy to maintain as when a wider variety of materials is used.

The amount of food added must match the ability of the worms to eat it. Uneaten kitchen scraps will soon putrify, souring the bed and creating unpleasant odours. All owners of earthworm cultures must learn to master this aspect of management.

Foodstuffs such as poultry pellets and meals are ideal for fattening up worms for fishing. Two hundred grams will last 2000 worms about 3-4 days. Wet them before adding to the bed.

Squeeze test

Management Good management involves the following:

* Match food supply to the ability of the worms to use it. As a rough guide, 2 kg of worms need about 1 kg kitchen scraps or the equivalent per day. Two kg of earthworms will comprise about 2400 fat worms, 4000 breeders or 9000 'pit- run' (mixture of all sizes in a culture bed).

* Keep the bed at the right moisture content. Beds under cover will need to be sprinkled every 2-7 days, depending on the time of the year. Good drainage must be provided for outdoor beds. Base moisture management on the squeeze test (page 11), not on a guess. The presence of white worms in the bed indicates that the bed is too wet; it could also be too acid.

* Good aeration of the bed is maintained by loosening it every couple of weeks with a fork of appropriate size. Be careful not to disturb the worms more than is necessary.

* Try with appropriate shading and insulation to keep the temperature of the bed in the range 12-25°C. That is not possible in some localities at some times of the year, but the nearer you get to this optimum, the faster will the worms grow and produce vermicompost.

* Check the pH of the bed from time to time. Try to keep the pH in the range 6-8. When feeding mainly with manure from grass-fed animals, it may not be necessary to adjust pH. When the food is mainly kitchen scraps, it will be necessary to give a sprinkling of limestone and/or dolomite and/or wood ash and/or crushed egg shells from time to time.

* It may be necessary in some areas to prevent flies from breeding in the bed. A cover of fly screen should be enough, but it may sometimes be necessary to spray the surface of the bed.

* A well managed earthworm culture will have a pleasant earthy odour. Sourness or other unpleasant odours call for changes in management.

15

1 )

Culture of White Worms These worms make excellent food for small fish such as

those kept in aquariums. Given the right conditions they multiply rapidly.

Dishpans or similar shallow non-porous containers should be used. The best culture medium is a light loam soil that does not easily harden when dry but at the same time is not sandy. A depth of 6 to 8 cm is best. Pieces of slate, stone or glass on the surface improve the culture conditions. The optimum temperature is 20°c but there is some latitude.

The culture should be rather more moist than for the other species so that the worms can move around freely. But it should not be so wet that they have to come to the surface. Water should be added by frequent and light sprinkling, not pouring. There should be no collection of water in the bottom of the container. If there is it must be removed by pouring or draining. The container should be partly covered to reduce evaporation but to allow free access to air.

The best food is cereals such as oatmeal, pieces of boiled potatoes with the skins attached, bread, and biscuit crumbs. A small amount should be mixed throughout the culture when it is set up but extra, small amounts should be inserted into the soil at frequent intervals (say 4 to 6 days). Only add an amount that can be eaten in a reasonable time, and place it near where the worms are found rather than scattering it over the surface of the soil. Some mould growth on the food does not seem to harm the worms. A culture that attracts a few Drosophila (vinegar flies) is often in optimum condition but a souring culture is to be avoided. Addition of small quantities of crushed bone helps keep the culture in good condition.

Place the starter worms in groups in only a few spots; this facilitates breeding.

Harvesting Techniques Experience shows that it takes about 6 months to produce Tiger worms attracted to egg

vermicompost of excellent quality. Then you need to separate the worms from the vermicompost. The technique you use depends on the size of your operation and o n your aims. * If you just want a few fat worms for a fishing expedition, all

you really need do is to bury some particularly tasty food, such as a broken egg, poultry feed or sheep dung, in one corner of the bed. Some. hours later this food will have attracted many worms to it, and it will be a simple matter to get plenty from this congregation.

* You have several options if you want to separate worms and vermicompost. The simplest technique is to pile the contents of the bed into a cone on a solid surface in a brightly lit area. The worms will move down into the cone, so allowing you to repeatedly remove the top several

16

centimetres of worm-free vermicompost. A small amount of hand sorting at the bottom of the cone will finish the job, or you can use this remaining mixture to seed a new bed. For larger operations, a rotating screen such as that

illustrated will be needed, but again, it may be found useful to first allow most of the worms to separate themselves from the vermicompost as outlined above.

Rotary screen separator

Earthworm casting as seen through a Scanning Electron Microscope Maqrutication x 35

Vermicompost - the mixture of materials of an earthworm culture bed - will be almost pure castings if the bed has been left for many months without the addition of new food. But commercial vermicomposts will usually be mixtures of castings, bed materials and uneaten food. Generally, the higher the proportion of castings in the vermicompost, the richer will it be as a source of many plant nutrients.

Vermicompost has been described as the 'most perfect plant food known to man', and as 'much superior to the best garden compost', and 'the richest topsoil known to science for potted plants or for mulching the flower garden'. While vermicomposts are most useful materials, these claims are a little exaggerated, as we shall see.

pH Microbial decomposition of plant materials, whether in a

compost heap or in earthworm casts, produces a compost which is near neutral in pH (typically pH 6.5-7). However, vermicomposts can be quite alkaline (one tested had a pH of 7.8) if excessively large amounts of liming materials have been added to the culture bed. On the other hand, if the bed has been allowed to sour, the vermicompost produced can be

17

quite acid. Check the pH of each new batch before using it on plants which might be harmed by materials which are too acid or too alkaline.

Salinity Some vermicomposts can be fairly saline because of the

release of soluble nutrients during decomposition of feed and bedding materials. This salinity will rarely cause your garden plants any problems, but if you want to use vermicompost by itself as a medium in which to germinate seeds or grow plants, you would be wise to leach the vermicompost soon after potting. Leach with an amount of water equal to about twice the volume of vermicompost; give a garden plant a boost by pouring·the leachate around its roots.

Nutrient Content 'Rubbish in: rubbish out' is a phrase used to describe what

happens with computers, but it also applies to earthworms. The vermicompost they produce is only as rich in plant nutrients as the richness of the materials eaten. Nutrients are not created during passage through earthworms, but the availability to plants of the nutrients already present may be greatly increased. This statement applies equally to plant nutrients and to toxic elements such as cadmium.

The table summarises the results of analysis of vermicomposts from several countries for total contents of nutrients.

Detail of the structure of an earthworm casting, showing how the remnants of plant parts and mineral particles are stuck together. Upper M:"gnif1cat1on x 260, Lower Maqrufication x 450

Nutrient Concentration in dry vermicompost

Range Average percent

Nitrogen Phosphorus Potassium Sulphur Calcium Magnesium Iron

Manganese Zinc Copper Boron Molybdenum

1.1-4 0.3-3.5 0.2-2.1 0.24-0.63 1-2.2 0.3-0.6 0.4-1.6

parts per million

270-950 185-1005 22-380 6-46 18-77

2 1.2 1 0.4 1.5 0.4 0.7

465 580 106 23 47

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The concentrations of major nutrients in vermicomposts are similar to those in garden composts. By comparison with manufactured fertilizers and the manure of grain-fed animals, the concentrations of major nutrients are not high, but the nutrients are present in a variety of forms ranging from soluble (immediately available) through slow-release to relatively unavailable. As with garden composts, large applications of vermicomposts to a garden soil build up the humus content of that soil and its ability to supply a steady stream of nutrients.

As the carbon to nitrogen ratio of thoroughly worked vermicompost will be around 12-15, it will act as a slow-release source of soluble nitrogen for plants as it decomposes.

Whether a vermicompost is or is not better than a compost made from the same materials has not been proven.

Published analyses of vermicomposts have shown that they usually contain high concentrations of trace elements. These trace elements appear to be present in forms which are readily available to plants. In fact, if the materials from which the vermicompost was made contained a high concentration of a trace element, it may be that the concentration in the vermicompost is toxic to plants grown in it. One known hazard is from the manure of pigs which have had copper added to their diet. If such a vermicompost is used to make up about one-third or more of the volume of a soil-less potting mix, plants can suffer from copper toxicity. Vermicomposts produced in galvanized containers may have a concentration of zinc which is toxic to plants when the vermicompost is used as part of a soil-less potting mix. Toxic levels of boron might be introduced into vermicompost via the glue of cardboard cartons. These problems should not arise when vermicomposts are applied to soils. Generally, vermicomposts are excellent sources of trace elements.

Zinc toxicity in stocks, produced by including vermicompost made from domestic wastes into a soil-less potting mix. Lett: Control mix: Middle Control mix plus 30% verrrucornpost Right Control mix plus 30% verrrucornpost plus additional trace elements. All pots had received regular liquid feed 1ng with N and K

.. ,,

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Weed Seeds Vermicomposts made from cow, sheep and horse manures

usually contain seeds from the plants eaten by these animals. Many seeds are either not eaten by earthworms or pass unharmed through their intestines. These seeds can be killed by sterilizing the vermicompost with methyl bromide or steam, but this is expensive, hazardous, and unnecessary. If there are seeds in the food you are giving your worms, the best way to get rid of most of them is to first allow the food to spend a week or two in a hot compost heap. You probably won't get rid of all of them, but the numbers of viable seeds will be greatly reduced. An alternative during the summer is to solarize the vermicompost before using it. Spread it out in a layer no more than 60 mm thick on concrete or asphalt where it will be in full sun for most of the day. Cover tightly with thin clear plastic film and leave for a couple of days.

Plant Hormones Extravagant claims have been made for the beneficial

effects of various vitamins and p lant hormones contained in vermicomposts. The small amounts of these substances in vermicomposts might occasionally benefit some plants, but the concentrations are very variable and tend to decline during composting. You would be unwise to rely on their benefits in the vermicompost you make or buy.

Physical Properties Well-made vermicompost has the rich black colour of

humus, has a pleasant earthy smell and is granular in appearance. It is capable of holding a considerable amount of water. However, it can become hard to rewet if it is allowed to dry out - especially if it has first become compacted into lumps. Wetting agents can aid rewetting. These problems are minimised if the vermicompost is used in mixtures with other materials.

Using Vermicompost Vermicompost is expensive to buy and only small amounts

can be produced by the vermicomposting of kitchen wastes, so vermicompost is used mainly for producing plants under intensive conditions.

Potted Plants Vermicompost should make up no more than about one

third of the volume of a potting mix. Any more can give a mix which is too fine. You can use the vermicompost to improve a cheap bought potting mix or you can mix it with other materials you have.

I

~ . .

The products of verrruculture

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When used at the rate given above, all vermicomposts will provide enough trace elements for a year or two of plant growth. This will probably be enough until the plant needs repotting. Do not use fertilizers containing added trace elements if you have used vermicompost in the mix. When using vermicompost from an untried source, watch for symptoms such as distorted, mottled and dying older leaves. These will indicate that the vermicompost contains a toxic level of a trace element. Such toxicities will not be very common and you may never see them. But toxicities of copper have been produced by vermicomposts made from pig manures; zinc toxicity was produced in plants growing in a mix containing vermicompost from a domestic source. Repot immediately you see symptoms such as leaf distortions and off-colours and your plants should soon recover.

Most vermicomposts tested so far have been able to supply an adequate amount of potassium for many months of vigorous plant growth. Most should also supply enough sulphur for a few months even when the water you use is low in sulphur, as is rain water.

The main deficiency likely is of nitrogen. Some vermicomposts contain much soluble nitrogen, but others tested have contained almost none. These low-nitrogen vermicomposts will not be able to supply enough nitrogen to plants in mixes which have wood wastes (pine bark, sawdust)

Most vermicomposts can supply ample amounts of all nutrients except nitrogen when used 1n soil-less mixes Pots on left Control mix (all nutrients supplied), Other pots: various verrrucomposts .._ ~

added at 30% by volume. Top no nutrients or potassium (K) only ------------------------- supplied: Bottom. nitrogen (NJ only or nitrogen and potassium (NK) supplied

21

as the main other component. Even the nitrogen of vermicomposts containing much of their nitrogen in soluble form will soon be used up. The small amount released through the decomposition of organic nitrogen compounds will usually not be enough to supply growing plants in mixes containing wood wastes. The best of vermicomposts are unlikely to be able to supply enough nitrogen for vigorous plant growth for more than a couple of months even when the mix does not contain wood wastes. Supplementation with high-nitrogen fertilizers will soon be necessary. Blood-and- bone and hoof-and-horn are two natural organic slow-release sources of nitrogen. You can also use IBDU or a liquid feed of your choice. If nitrogen only is required, you can use a solution containing 0.3-0.5 g ammonium nitrate per litre.

You can supply more nutrients later by sprinkling vermicompost onto the surface of the mix in the pot, or you can make a liquid manure (see below).

Liquid Manure A useful liquid manure can be made by soaking one volume

of vermicompost in 10 to 15 volumes of water. The composition of this liquid manure will of course vary with the richness of the vermicompost. Typically, it y,.,ill contain from near zero to perhaps 200 ppm nitrogen (50-100 might be counted on), about 100 ppm potassium, a few ppm phosphorus, around 1 0 ppm sulphur and variable amounts of al I other nutrients.

Gardens Vermicompost can be used in much the same ways as

ordinary compost is used. It can be dug in or used as a top dressing; it can be used as a side dressing between rows of young plants.

The following description applies only to the common European earthworms. Native and tropical worms are usually very different. 1s

Anatomy Earthworms, as everyone knows, are usually red or pink, long,

cylindrical, and divided into rings or segments. Closer inspection shows that adult specimens have a clitellum, often called a saddle because it is a thickened, usually paler coloured, rather saddle- shaped area on the upper and side surfaces of the body. The clitellum is near the head end of the body, covers about 5 to 10 segments, and is a part of the reproductive system.

The colour is usually more intense on the upper surface because of the presence of pigments, usually reddish brown or red, in the

22

cells of the skin. But much of the colour is due to the haemoglobin in the worm's blood, the same red pigment as in human blood. The haemoglobin is not in red corpuscles as it is in our blood, but in solution in the blood plasma. Earthworms have no special breathing organs - oxygen is absorbed and waste gases are eliminated b y diffusion through the skin from a network of fine blood vessels just under the skin surface. The respiratory gases must be dissolved in water to be transferred; gland cells in the skin secrete mucus to keep the surface moist and to lubricate the body as it moves through the soil. This is why earthworms are moist and slippery to touch, and because they must constantly replace water lost by evaporation from the surface, they cannot live in very dry soils.

Scanning Electron Microscope photograph of an earthworm showing detail of segments and setae Maqrutication x 11

The body structure of an earthworm is basically a rather simple arrangement of one tube inside another. The outer tube is the muscular body wall, and the inner tube the digestive system, with a fluid-filled space separating them.

The body wall has two sets of muscle fibres, the circular muscles, which encircle each segment just under the skin, and inside them the longitudinal muscles, which are usually a much thicker layer, continuous through the length of the body and arranged in a number of blocks around the circumference. The muscle layers are bounded internally by a thin membrane. Small spines, called setae, are embedded in the body wall and project to the exterior. Each set has a cone-shaped arrangement of muscle fibres attached to its basal section and these muscles are used to push the setae outwards from th= body wall and to retract them. The setae are arranged in symmetrically spaced pairs in most species. In the common garden and pasture species there are four pairs on each segment (except the first and a few of the very last) - two pairs on each side, towards the u nder surface. In many native species that might be found in bushland there are more than eight setae per segment and they may form an almost complete ring around the segments.

The fluid-filled space between the body wall and the digestive system is divided into more or less water-tight compartments by

23

membranes called septa, which are usually slightly muscular. They correspond in position with the external grooves between segments.

How They Move Movement involves a quite complex set of co-ordinated actions

and reactions of the circular and longitudinal muscles, the setae, the septa, and the fluid-filled body cavity. Suppose an earthworm is moving forward through a formed burrow. In a region of the body about half way back from the head it relaxes the circular muscles and contracts the longitudinal muscles. This will shorten the segments and make this part of the body shorter than before. Since the fluid in the body cavity will not compress, the segments must bulge (dilate) sideways, pressing the outer surface against the walls of the burrow. The muscles controlling the setae in the dilated segments then push the setae outwards so that they grip the walls of the burrow. Then, in the segments ahead of the dilated portion, the longitudinal muscles relax and the circular muscles contract. Again, because the fluid in the body cavity of these segments will not compress, the segments elongate and become smaller in diameter and the worm's head moves forward. Now the whole process is reversed, so that the front segments grip while those behind let go. A wave of contraction passes along the longitudinal muscles from front to rear and the body is pulled forward, expanding in diameter to fill the burrow as it comes. The process is smooth and progressive, more like waves of contraction and relaxation following each other than a step-by-step process. Similar movements are made to propel a worm across the soil surface, but here only the underneath setae are used. Making new burrows involves similar movements. If a crack or natural soil space is available, the worm will elongate and insert its head end into the space, then take hold with its setae and expand sideways by contracting the longitudinal muscles, pushing the soil particles outwards to form the burrow. If no suitable space is available to push the head into, the worm will swallow soil, surrounding and

Mouth of an earthworm. Magnification x 21

Close-up of earthworm setae. Magnification x 125.

24

Septa Intestine Gizzard Crop Seminal vesicles Retractor muscles of pharynx

Pharynx

7 Muscle layers of body wall Skin Ovary Testes

,

gripping suitable sized pieces with its everted (pushed inside out) pharynx and plucking them off by retracting the pharynx (see description of digestive system below). Soil swallowed like this is passed through the body and excreted as casts.

Digestion, Nerves, Blood The d igestive system is essentially an unbranched tube running

from the mouth at the extreme front to the anus at the other end of the body. Just inside the mouth the tube expands into a strongly muscular pharynx. The pharynx can literally be turned inside out so that it protrudes through the mouth to surround and grasp pieces of food or soil, and then as it is pulled back through the mouth by strong retractor muscles the food comes with it into the alimentary canal.

dorsal blood vessel cuticle

intestinal blood vessel

circular muscles

typhlosole

longitudinal muscles

intestine

fluid-filled body cavity

segmental nerve ganglion on main nerve cord

25

Behind the pharynx is a less muscular and narrower oesophagus, which passes back to a thin-walled crop, a kind of temporary storage container for food until it passes back into a very strong- walled muscular gizzard. The gizzard macerates the food before it passes through a fairly narrow valve into the thin-walled, wide intestine. The intestine extends back through the remainder of the length of the body to the anus.

An earthworm has a "brain", a small bundle of nerve tissue located on top of and right at the front of the pharynx. It is connected by a ring of nerve cord a round the pharynx to a nerve cord that runs along the middle of the lower surface of the body cavity, under the gut, attached to the membrane that separates the muscle layers from the body cavity. In each segment the nerve cord is enlarged to form a small knot, and small nerve fibres arise from each ganglion to provide nerves for the muscles and other organs in the segment.

The largest blood vessels are the dorsal vessel, which runs along the upper mid-line of the gut, and the ventral vessel, along the lower mid-line of the gut. Blood is moved forward by waves of contraction of the dorsal vessel, then is pumped into the ventral vessel by several (usually 3, 4 or 5) pairs of hearts, which are prominent vessels surrounding the oesophagus, one pair in each of several successive segments. The blood then flows back along the ventral vessel. In each segment small vessels branch from the ventral and dorsal vessels to supply blood to the tissues, to absorb oxygen and release carbon dioxide through the skin, and to return the blood to the dorsal vessel for recirculation.

Breeding Earthworms have both male and female reproductive organs in

the one individual. There are two pairs of testes (male organs) and one pair of ovaries (female organs) in most species. Sperm cells, produced by the testes, are stored in special sacs called seminal vesicles, located in the body cavity adjacent to the testes. Paired ducts from the seminal vesicles open to the exterior (on segment 15 in common introduced species), one on each side towards the lower surface of the body. Ducts that carry eggs from the ovaries open to the exterior in a similar position on segment 14. Ahead of these male and female pores, on segments 9 and 10 in common introduced species, are the openings of paired spermathacae, which are storage sacs for sperm cells after mating has occurred.

Tiger worms mating

26

During mating, two worms align themselves in a head to tail attitude, with their lower surfaces touching each other over a length of about 35 front segments. A thick layer of mucus is produced, covering each worm from near the front end t o a few segments behind the clitellum. Sperm cells are then discharged by both worms; the sperms from each worm find their way to the spermathecae of the other, where they are stored. The two worms then separate. Subsequently, the clitellum secretes a layer of albuminous material that forms a broad ring around the body. The worm then works its body backwards from inside this ring. As the ring passes over the female pores, eggs are laid inside it, and as it passes over the spermathecal pores sperm cells are released to fertilise the eggs. The worm continues to work its body out of the ring, and as the ring passes over the snout its two ends are closed so as to form an oval egg case or cocoon. The cocoons are deposited in the soil and the fertilised eggs then develop and grow into small worms, taking something like 2 to 5 weeks to hatch, depending very much on the temperature. The number of eggs per cocoon is variable, but usually only one or two worms succeed in developing and emerging from a cocoon. The n umber of cocoons produced per worm varies greatly from species to species; for tiger worms it may be several hundred per pair per year. Common introduced species have two main breeding periods during the year, usually in late winter-early spring and autumn. Young worms of the most common species grow to maturity in about 6 to 9 months. In laboratory conditions they live for several years, but in natural conditions their life span is probably much shorter, probably not more than about a year.

In some species reproduction can be achieved by self- fertilisation; such species include some that apparently do not mate at all and some that are able to reproduce with or without mating.

27

There are two main groups of earthworms in Australia, one including many species, mainly native to this country, the other including only a small number of species that have been introduced (accidentally) by man.

The native species are not easily identified. Most of them are found only in a reas with native vegetation that have been little disturbed by farming, horticulture or intensive settlement, although a few species of this native group are common in man-influenced environments. A few tropical species of the same general type were, it seems, introduced by immigrants long ago and are now widespread in man-influenced environments of tropical and subtropical regions of Australia.

A rather small number of species of the earthworm family Lumbricidae has been introduced in the last two hundred years, from western Europe. The same species are now found in most temperate regions of the world, and they are the dominant species of man-modified habitats throughout southern Australia.

Below is· a checklist, which will help you to identify some o f the most common species of earthworms that you may find in pastures, croplands and gardens in Australia. You should understand that these are introduced species and that the checklist will not enable you to identify the native species that you are likely to find in forests or other little-disturbed habitats.

It is very difficult to identify earthworms unless they are adult individuals. Adults may be distinguished by their clitellum or saddle, a band of tissue, usually slightly swollen and different in colour from the remainder of the body, that forms a ring or saddle-shaped thickening around or across the top and sides of a few segments of the body. It is always closer to the head than to the tail, so this makes it easy to tell the head from the tail.

You will find it helpful to have a magnifying glass (5x or 10x magnification would be suitable) to see more clearly the features used in the checklist to distinguish species.

So, if you want to identify earthworms, begin by selecting individuals that have a clitellum. You will have to count some of the segments of the body. The segments are the ring-like

sections, separated by grooves, into which the body is divided. CHECKLIST

Follow the numbered steps. Step 1. Start from the head and count how many segments there are before the beginning of

the clitellum. If there are less than 17 segments in front of the clitellum, i.e., the clitellum begins

quite close to the head, go to step 2 in the checklist. If there are more than 20 segments in front of the clitellum i.e., the clitellum is about a

third or more of the way along the b ody, go to step 4 in the checklist. Step 2. You have a native species or one o f the related introduced tropical species.

Look very carefully at the segments behind the clitellum, using your magnifying glass if necessary.

Is there a zone of the body, about a quarter of the total length from the tail end, where there are a few very narrow segments that are paler in colour than the segments behind or in from of them?

Look also at the arrangement of the setae (see previous section of this booklet on the anatomy of earthworms) on segments near the tail. Can you see, on each successive segment, pairs of setae (each pair is on a slight swelling) arranged in an alternating pattern as shown in the diagram.

If you can see either or both of these things, the species is . . . Pontoscolex corethrurus.

You can check this identification by looking carefully at the clitellum, which begins about segment 15 and extends to about segment 23; it nearly surrounds the body on

28

these segments, but is not developed over a small proportion of the earthworm's ventral (bottom) surface.

This species is common in tropical and warm temperate regions of Australia, especially in cultivated lands. It is sometimes the only species present and it may be found in large numbers.

If you can not find these features go to step 3 in the checklist. Step 3. Is the clitellum very distinct, ring-shaped and completely surrounding segments 13-16

or 14-16? If you collected the earthworm in the southern cool temperate regions of Australia, in

pasture, croplands or gardens, it is probably ... Microscolex dubius or Microscolex phosphoreus.

These are small worms, usually not more than about 70mm long and 3-4mm in diameter. They are pale in colour, with a yellow-brown clitellum, and are rather sluggish in their movements. M. phosphoreus, as its name implies, is phosphorescent; if you put living specimens in a very dark place you will see that they glow with a slightly greenish white light.

If you collected the earthworm in pasture, croplands or gardens, in a tropical or subtropical region of Australia, it is probably a species of the Pheretima-group of genera. This is a group with many species and they are very difficult to identify. They are usually strongly pigmented, red, green or brown, with the clitellum paler than the adjacent segments. Some of the common species are very active and will lash their bodies and jump about when disturbed. They have many setae on each segment, closely arranged in a ring, and you may see these with a magnifying glass or feel them as a slight surface roughness if you pass the body gently through your fingers.

Species of the Pheretima-group that are most common in farmlands and gardens have been introduced by man, but there are also many native species of this group, as well as species of other native groups that are closely similar.

Step 4. Look carefully at the upper surface of the body, in front of the clitellum. Is it dark coloured (red, purple, brown, dark grey) or pale (pink, cream, greenish, pale grey)?

If it is dark coloured, go to step 5. If it is pale, go to step 11.

Step 5. Is the colour of these segments a fairly uniform red-brown or purplish-red, with a sheen that is iridescent in bright light?

If so, go to step 6. If not, go to step 9.

Step 6. Is it a small to medium-sized earthworm, with conspicuous white papillae (broad flat lumps), widely separated, one on each side on the under surface of segment 15, and rather similar white papillae on segments 9, 10 and 11 (sometimes also 12) that more or less meet in the middle of the under surface, giving the appearance of a nearly continuous swollen white patch? Does it live near the soil surface, not in permanent well-defined burrows, and produce small casts at the soil suriace?

If so, it is . . . Aporrectodea caliginosa. If not, go to step 7. Aporrectodea caliginosa is the most common earthworm of pastures and cultivated

lands in temperate regions of Australia and of the world. It may be particularly numerous in the soils of fertile pasture lands and it is one of the most important species in improving the structure and the chemical fertility of soils. It is not always pigmented, as described here, and you will see that it appears again in this checklist under step 12 below.

Step 7. Is it a large earthworm, 100-300mm long, with conspicuous white papillae (broad flat lumps), one on each side on the under surface of segment 15, but lacking the prominent papillae on segments 9-11 ( or 12) described above for Aporrectodea caliginosa? Does it have a deep burrow with an obvious surface opening marked by one or more large casts?

If so, it is . . . Lumbricus terrestris.

29

This is the classical "text-book" earthworm. It is not widespread in Australia, but is known from southern New South Wales, Victoria and Tasmania.

If not, go to step 8. Step 8. Is it an active worm, 30-110mm long, lacking papillae on segment 15 as described above

for L. terrestris? Does it live near the soil surface, but not in a distinct deep burrow marked by surface

casts? If so, it is almost certainly .... Lumbricus rubellus. This species is widespread in farmlands and gardens in the better-watered regions of

temperate Australia. Very small specimens that correspond to this description may be Lumbricus castaneus.

Step 9. Does the worm have a very distinctive banded colour pattern of alternate red and yellow, especially visible when the b ody is stretched out?

If so, it is . . . Eisenia fetida. This is the "tiger worm", common in compost heaps and manure heaps, and widely

supplied as fish bait. It is very useful as a decomposer of compost or manure, but is not a useful species to introduce into farmlands or gardens.

If not, go to step 10. Step 10. Is it a large, dark grey or grey-brown, active worm, with a sheen that is iridescent in

bright light, up to about 150mm long, living quite deep in the soil, but with no distinct burrow opening at the surface?

If so, it is . . . Aporrectodea longa. Step 11. Is it an unusually thick, pale grey or bluish-grey sluggish worm, with a prominent cream

or brownish-cream clitellum and a distinct yellow tip to the tail? If so, it is . . . Octolasion cyaneum. Octolasion cyaneum is usually found in pastures or gardens of rather low fertility in

the more humid regions of southern Australia. If not, go to step 12.

Step 12. Is it a pale pink, greyish-pink or greenish worm with a pink head, and with prominent pale papillae {broad flat lumps) widely separated and one on each side on the under surface of segment 15? Does it have rather similar white papillae on some or all of segments 9, 10, 11, 12, 13 that more or less meet in the middle of the under surface, giving the appearance of a nearly continuous swollen white patch?

If so, it is either . . . Aporrectodea caliginosa or Aporrectodea rosea or Allolobophora chlorotica.

It is not easy to separate these species. They have rather similar habits and are common and often very numerous in pasture, croplands and gardens in southern Australia.

Allobophora chlorotica is sometimes green, and is then readily distinguished from the other two species, but it may be pink or greyish-pink. It tends to coil tightly and lie still when disturbed, while the other two species will move away from any disturbance.

30

Biology of Earthworms. CA Edwards and J.R. Lofty, 1977 (Chapman and Hall)

The World of the Soil. E.J. Russell, 1959 (Collins/Readers Union)

The Earthworm Book. Jerry Minnich, 1977 (Rodale Press) Earthworms: Their Ecology and Relationships with Soils and

Land Use. K.E. Lee, 1985 (Academic Press) Earthworm Ecology from Darwin to Vermiculture. Edited by

J.E. Satchell, 1983 (Chapman and Hall) Worms Eat My Garbage. Mary Appelhof, 1982 (Flower Press,

Kalamazoo)

31

Thanks are due to the following for help in the preparation of the second edition of this booklet: Tildabrook Worm Farm, Caparra, NSW; Earthworm Supplies Queensland, Bulimba, Old; Wonderworm Farm, Welby, NSW; Bundaleer Worm Farm, Oakford, WA; The Big Fat Worm Farm, Nambucca Heads, NSW; Wrigglers of York, York, WA; Vermiculture Industries, Camperdown, NSW; David Stephen, Taroona, Tas; Mike Temple-Smith, Launceston, Tas; John Greenslade, CSIRO Division of Soils, Canberra; Cindy Snyder. CSIRO Division of Soils, Brisbane; Alister Spain, CSIRO Division of Soils, Townsville.

Text Kevin Handreck, Ken Lee Line Drawings: Pam Brinsley Photo credits: The Big Fat Worm Farm, Nambucca Heads, NSW-

Cover, pp. 11, 13; Wonderworm Farm, Welby, NSW-pp. 9 ( upper), 15; Bundaleer Worm Farm, Oakford, WA-p. 9 (lower); Vermiculture industries, Camperdown, NSW-p. 10; Chris Payn, Organic Growing (magazine), Tas.-p. 7; Stewart McClure, CSIRO Division of Soils- PP- 16, 17, 22, 23; Cliff Hignett, CSIRO Division of Soils-5; John Coppi, CSIRO Division of Soils-2, 9 (margin), 14, 15 (margin), 18, 19. 20.

,

Cover: Admiring a beautiful native Australian earthworm

411lt CS I RO

AUSTRALIA ISBN O 643 04237 7