Vermiculture in Egypt: - FAO - Regional Office for the Near East and

3.4. Vermicompost „teas‟ in Ohio, USA
These aqueous vermicompost extracts or „teas‟ are much easier to transport and apply,
than solid vermicomposts, and can duplicate most of the benefits of vermicomposts
when applied to the same crops. Additionally, they can be applied to crops as foliar
sprays.
Work at The Ohio State University has shown that vermicompost „teas‟ increased the
germination, growth, flowering, and yields of tomatoes, cucumbers, and other crops in
similar ways to solid vermicomposts. The aerated, vermicompost „teas‟ suppressed
the plant diseases Fusarium, Verticillium, Plectosporium, and Rhizoctonia to the same
extent as the solid.
Vermicompost „teas‟ also suppressed populations of spider mites (Tetranychus
urticae) and aphids (Myzus persicae) significantly.
Additionally, they had dramatic effects on the suppression of attacks by plant
parasitic nematodes such as Meloidogyne on tomatoes both in terms of reducing the
numbers of root cysts significantly and increasing root and shoot growth and Physicochemical
characteristics of the feed and optimum worm density are important
parameters for the efficient working of a vermicomposting system. The results
showed that E. fetida growth rate was faster at higher stocking densities; however,
biomass gain per worm was faster at lower stocking densities. Sexual maturity was
attained earlier at higher stocking densities. Growth rate was highest in 100% cow
dung at all the stocking densities when compared to textile mill wastewater sludge
containing feed mixtures. A worm population of 27–53 worms per kg of feed was
found to be the most favorable stocking density. Even when the physical conditions
(temperature and moisture) and quality of waste (size, total organic carbon, total
nitrogen, and total available phosphorus) are appropriate for vermicomposting,
problems can develop due to overcrowding of earthworms. This study clearly showed
that when E. fetida was allowed to grow at different stocking densities the worms
grew slowly at higher stocking densities. The maximum body weight of earthworm
was higher at lower stocking densities. Maturation rate was also affected by stocking
rate. Worms attained sexual maturity earlier in crowded containers. Worms of same
age developed clitellum at different times at different population densities. The results
indicate that population of 27–53 worms per kg and 4–8 worms per 150 g/feed
mixture is optimum (Garg et al., 2008).
Most of the research on utilization of earthworms in waste management has focused
on the final product, i.e. the vermicompost. There are only few literature references
that have looked into the process, or examined the biochemical transformations that
are brought about by the action of earthworms as they fragment the organic matter,
resulting in the formation of a vermicompost with physicochemical and biological
properties which seem to be superior for plant growth to those of the parent material.
It has been reported that the storage of organic wastes over a period of time could
alter the biochemistry of the organic matter and could eventually lead to the
stabilization of the organic waste. Nevertheless, we hypothesize that adding
earthworms to the organic wastes would accelerate the stabilization of these wastes in
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