Charne Myburgh
ARC-Grain Crops Institute, Potchefstroom
Photo:https://upload.wikimedia.org/wikipedia/commons/6/60/Earthworm.jpg
E
arthworms are mostly
overlooked and greatly
underestimated, and yet
they play a very important
role in the soil. These worms are
referred to as the engineers of the
soil, and with good reason. They
improve soil structure through their
burrowing activity in their search
for food. During this process they
loosen soil particles and form tunnels through the top layers of the
soil. These tunnels assist with the
aeration and water drainage within
the soil. When the earthworms
make these burrows they pull organic material down into the soil,
which in turn improves soil quality.
The organic material which they
feed on is in turn released as plant
available nutrients. Earthworm
casts produce an ideal crumb-like
texture to the soil and studies have
found that these casts contain more
nitrogen, potassium, phosphorous,
magnesium and calcium than the
surrounding soil.
Furthermore, nematode numbers as
well as pathogenic fungi in soil are
controlled in the presence of earthworms when they are ingested together with organic material and
soil.
Microbial activity is stimulated in
the presence of earthworms. The
significance in this is that a good
soil microbiology is very important
as soil microorganisms and enzymes regulate nutrient cycling.
Microorganisms are involved with
the decomposition and mineralisa-
tion of complex organic materials.
Earthworms are also used for scientific evaluations of farming or degraded soil as they are excellent
indicators of pollution and soil
changes. These tests observe the
interactions that exist between environmental chemicals and biota
and focuses on different biological
organisation levels, which is used as
a parameter for toxicity. As these
worms are constantly in contact
with each other, the soil, plants and
microorganisms, they are ideal for
these tests. As soon as any disturbances take place in the soil, the effects thereof will be observed in the
earthworm community in terms of
survival, biomass and reproduction.
A favourable habitat is created for