Gauteng Smallholder Gauteng Smallholder August 2017 | Page 37

From page 33
IN THE GARDEN
of things. He said, “It
may be doubted
whether there are many
other animals which
have played so important
a part in the history of
the world, as have these
lowly organized crea-
tures.”
Earthworms are some-
times known as 'ecosys- Indigenous earthworms differ from those used in worm farms, or vermiculture
pasture soils, decomposing
organisms. Increased
tem engineers' because they
dung
and
plant
litter
and
microbial activity facilitates
significantly modify the
processing
literally
tons
of
the cycling of nutrients from
physical, chemical and
organic
matter
per
hectare
organic matter, so nutrients
biological properties of the
each
year.
They
also
recycle
such as phosphorus and
soil profile. These modifica-
nitrogen become more
tions can influence the habitat leaf litter under trees and
shrubs.
readily available to plants
and activities of other
after digestion by earthworms
Although earthworms derive
organisms within the soil
and being excreted in
their nutrition from micro-
ecosystem.
organisms, many more micro- earthworm casts.
They are important recyclers
organisms are present in their Earthworms can move large
of organic material.
faeces or casts than in the
amounts of soil from the
Earthworms, along with
organic matter that they
lower strata to the surface
bacteria and fungi, decom-
and also carry organic matter
pose organic material. So they consume. As organic matter
passes through their intes-
down into deeper soil layers.
are important in the process
tines, it is fragmented and
Their burrows also alter the
of making compost, but
inoculated with micro-
physical structure of the soil.
earthworms do the same in
35
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They open up small
spaces, known as pores,
within the soil.
When earthworms are
introduced to soils devoid
of them, their burrowing
can lead to increases in
water infiltration rates of
up to ten times the
original amount. This
brings water and soluble
nutrients down to plant
roots. Burrowing also
improves soil aeration
(important for both plants and
other organisms living in the
soil) and enhances plant root
penetration. At the same
time, the burrows minimize
surface water erosion.
Plant and crop residue are
gradually buried by cast
material deposited on the
surface and as earthworms
pull surface residue into their
burrows.
Earthworms, like all creatures,
are part of food webs. Their
Continued on page 37