Agriculture Reference
In-Depth Information
6.
Food wastes
are readily available wastes that are expensive to dispose
in landfills or elsewhere and provide a good medium for growing earthworms if some
form of bulk material such as paper waste or compost is mixed with them to lower the
moisture contents.
or
restaurant wastes
7.
produced by mechanical separation, pressing, or sedimentation of
solids from the production washings. These solids are really excellent material for any
growth of earthworms, and there is no need for preprocessing or additives. They are
particularly suitable for outdoor windrow processing systems because they form a crust
over the bed that minimizes water loss at the same time it allows water to be added.
Paper pulp solids
are
8.
Brewery wastes
need no modification, in terms of moisture content, to grow earthworms.
Earthworms can process brewery wastes very quickly and grow and multiply rapidly in
them. The vermicompost produced from brewery wastes has a good structure and nutrient
content.
9.
Spent mushroom compost
is a good medium for growing earthworms, which are able to
break down the straw it contains into small fragments and produce a finely structured
material. However, the vermicompost produced may be low in plant nutrients.
10.
Urban garden wastes,
including grass clippings and tree leaves, are good growth media
for earthworms, particularly when they are first macerated and thoroughly mixed before
use (Huhta and Haimi 1988; Edwards 1995a,b). However, their production and avail-
ability tends to be seasonal, which makes production of a standardized vermicompost
year round difficult.
SPECIES OF EARTHWORMS SUITABLE FOR PROCESSING
ORGANIC WASTES
B
E
S
E
S
IOLOGY
AND
COLOGY
OF
UITABLE
ARTHWORM
PECIES
Many species of earthworms have potential for use in organic waste processing, but relatively few
have been used on a widespread scale and researched adequately. The species used most commonly
include
Eisenia fetida
and
Eisenia andrei
(brandling or tiger worms),
Eudrilus eugeniae
(African
night crawler),
L. rubellus
(red worm),
Dendrobaena veneta, Perionyx excavatus,
and
Perionyx
hawayana.
in sewage sludge has been
studied in detail (Neuhauser et al. 1988). These researchers concluded that all these species have
a range of optimum temperatures between 15 and 25
The growth of
E. fetida, E. eugeniae, P. excavatus,
and
P. hawayana
A
C for growth in sewage sludge, and all four
species produced most cocoons at 25
A
C. Over a period of 20 weeks,
P. excavatus
had the slowest
rate of increase in weight, and
E. fetida
grew slightly slower. Both
P. hawayana
and
E. eugeniae
reached their peak biomass in about 10 to 12 weeks, and
E. eugeniae,
which grew much faster,
began to lose weight after 14 weeks.
D. veneta
increased most in weight and took 16 weeks to
achieve maximum weight.
P. excavatus
produced the largest number of cocoons, and
D. veneta,
which produced the lowest number of cocoons, did not start producing cocoons for 10 weeks. The
other three species,
all produced similar numbers of
cocoons, with peak cocoon production occurring after 10 weeks.
It is also important to evaluate the number of live young earthworms that emerge from the
cocoons of each species. Cocoons from five species of earthworms,
E. fetida, E. eugeniae,
and
P. hawayana,
D. veneta, E. fetida, E. eugeniae,
P. e xcavatus,
were collected and allowed to hatch (Edwards 1988). Individual
cocoons were kept in organic waste under nonstressed conditions at 25
and
P. hawayana
,
C and were checked twice
per week to determine the number of cocoons that had hatched and the number of earthworm
hatchlings that were produced per cocoon. They concluded from their data that
A
E. fetida
produced
6 cocoons per earthworm per week (19 young earthworms),
D. veneta
produced 5 cocoons (19
young earthworms),
E. eugeniae
produced 11 cocoons (20 young earthworms),
P. e xcavatus
