Maximum Yield Australia/New Zealand March/April 2020 | Page 44

Nematodes act as a taxi cab for
other bacteria and fungi. They carry
microbes on their surface and in their
digestive system as they travel along
roots in the soil.
HOW TO SUPPORT SOIL
MICROORGANISMS
Protozoa stimulate bacterial
populations. When they graze
on bacteria, much like when
you prune a tree, growth is
enhanced. They also suppress
plant diseases by competing
with and feeding on pathogens.
They themselves are an important food
source for other soil organisms.
Protozoa live in the rhizosphere next to
roots, where there are plenty of bacteria
to eat. Moisture is important for
protozoa because they travel by water.
“
NEMATODES
Nematodes act as
a taxi cab for other
bacteria and fungi.
They carry MICROBES
on their surface and
in their digestive
system as they
travel along
roots in the soil.”
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Maximum Yield
Nematodes are non-segmented worms
that are only about 0.05 mm in diameter
and 0.05 mm long. They feed on a wide
variety of soil organisms. Some strains
feed on bacteria and fungi while others
consume plants, algae, and other
nematodes. When they eat bacteria or
fungi, ammonium is released into the
soil in a form plants can use.
Their grazing stimulates bacterial
growth, however, too many nematodes
can reduce bacterial populations,
which in turn decreases plant
productivity. Predatory nematodes, soil
microarthropods, insects, and parasitic
bacteria and fungi keep nematode
populations in balance.
While some nematodes can cause
plant diseases, others suppress them by
feeding on disease-causing organisms.
In fact, you can purchase beneficial
nematodes as a biocontrol agent at
most garden centres.
Beneficial soil microorganisms
thrive in soil that has
plenty of organic matter
and has not been
tilled. While tilling initially
releases a burst of nutrients,
it also destroys established
fungal networks. Over time,
organic matter becomes
depleted and microbial
populations shrink because
they have lost their food
source. Under no-till conditions,
small amounts of nutrients are
released every year and high levels of
organic matter are maintained.
Fall is the ideal time to add organic
matter to your garden so that it can
decompose over the winter. For great
results, simply mulch with compost,
straw, leaf litter, manure, or wood chips.
You can also chop and drop your spent
plants, and either leave them on top
of your soil or turn them under. Doing
this with legumes will add plenty of
nitrogen to your soil.
Cover crops also feed soil microbes.
There are 1,000 to 2,000 times more
microbes living around roots then there
are living in bare or tilled soil. Planting
a winter cover crop to a no-till field
will prevent nutrients from being lost
through erosion and leaching, and give
beneficial microbes a place to call home
with plenty of food nearby.
Synthetic fertilisers and pesticides
can do serious damage to microbe
populations. The salts in fertilisers
and chemicals in pesticides harm
microbes. Better to add organic matter
and amendments to the soil if you want
a thriving microbial population. When
your soil contains a diverse population
of microorganisms, you’ll find pests
tend to be less of a problem. However,
if problems do arise, organic pesticides
such as neem oil or soap sprays will
effectively treat infestations without
harming soil biology.
If you create an environment that is
favourable to beneficial microbes in
your soil, they will do many of your
garden chores for you. They will recycle
nutrients and create rich soil that will
grow a happy, healthy garden.