Agriculture Reference
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4.Methods of harvesting and processing of earthworms into animal feed protein, fish,
poultry, and pig animal feeding trials and use of earthworms in toxicological tests
(Edwards 1985; Edwards and Niederer 1988; Edwards and Bohlen 1992).
5.Development and testing of a range of technologies and systems of production of
earthworm protein and vermicomposts (Edwards 1985, 1988, 1995a,b).
6.Studies into the production of plant growth media processed by earthworms from organic
wastes, greenhouse plant growth trials, and their utilization on field crops. Amendments
of these growth media produce maximum plant growth (Edwards 1983; Edwards et al.
1985; Edwards and Burrows 1988).
Five main earthworm species were identified as potentially useful species to break down organic
wastes. These were
E. fetida
(or
the closely-related
Eisenia andrei
),
Dendrobaena veneta,
and
Lumbricus rubellus
from
the tropics. The survival, growth, mortality, and reproduction of these species were studied in detail
in the laboratory, in a range of organic wastes, including pig, cattle, duck, turkey, poultry, potato,
brewery, paper, and activated sewage sludge. All the species tested could grow and survive in a
wide range of different organic wastes, but some were much more prolific, others grew rapidly,
and yet others attained a large biomass quickly; these were all characters contributing in different
ways to the practical usefulness of the earthworms in producing vermicomposts or animal feed
protein. However, there were many species-specific differences in the biology and ecology of these
earthworms.
Most organic wastes can be broken down by these species of earthworms, but some organic
wastes have to be pretreated in various ways to make them acceptable to the earthworms, and not
all organic wastes will grow earthworms equally well. The characteristics of the different wastes
that have been tested are as follows:
from temperate regions and
Eudrilus eugeniae
and
Perionyx excavatus
1.
Cattle manure solids
are the easiest animal wastes in which to grow earthworms suc-
cessfully. Except when they are very fresh, they usually contain no materials unfavorable
to the growth of earthworms. Solids can be used, but it is much easier to produce good
vermicomposts in solids separated mechanically from slurries of cattle manures, which
are rich in nutrients for plant growth; moreover, the liquids can be added back to the
solids at a later stage in vermicompost production.
2.
Horse manure
is an excellent material for growing earthworms and needs very little
modification other than maintenance of good environmental factors in the waste. How-
ever, the earthworms do not grow as rapidly in horse manure as in pig or cattle wastes.
3.
Pig manure solids
are probably the most productive organic waste for growing earth-
worms. If the waste is in the form of a slurry, it is better if the solids are separated in
mechanical presses or by sedimentation. Pig wastes tend to contain relatively large
amounts of ammonia and inorganic salts, and unless these are washed out, the waste
may have to be composted thermophilically for about 2 weeks or longer before to
inoculation with earthworms. Pig wastes sometimes have a content of heavy metals,
particularly copper (Edwards 1988; Wong and Griffiths 1991). The processed pig waste
vermicomposts are high in nutrients for plant growth.
4.
Poultry wastes,
including chicken, duck, and turkey manures, contain significant amounts
of inorganic salts, urea, and ammonia, which may kill earthworms in freshly deposited
wastes. However, after removal of these materials through composting, washing, or aging,
earthworms grow well in them, and the vermicomposts produced are high in nutrients
for the growth of greenhouse or field plants.
5.
Potato wastes,
in the form of peel from the processed potato and frozen potato
industries, make ideal growth media for earthworms and need few modifications in terms
of moisture content or other kinds of preprocessing (Edwards et al. 1985).
usually
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