The Rural Voice, 2003-11, Page 321
Rhea
Hamilton -
Seeger and
her husband
live near
Auburn. She
is a skilled
cook and
gardener.
Gardening
Relationships below the soil
By Rhea Hamilton -Seeger
Gardeners all recognize good soil
when they sink their hands into it.
Cool, moist but not wet, smooth,
silky, almost oily.
We understand the workings of
compost and try valiantly to keep
things balanced and working away,
encouraging bacteria to break down
all that material so we can feed our
plants with what mother nature
intended. With the rich compost
comes the worms and more bacteria
working and living together entwined
into the eco system. But beyond what
we can see with our naked eye and
know from our studies there is still
yet another facet to this wonderful
interconnected world: fungus.
I can tell you are picturing
mushrooms in your lawn, fungus on
your old trees, even puffballs in the
forested sections (how lucky). But
the fungi I speak of are more minute
and more integrated than we could
ever imagine. Dr. Larry Peterson,
of the Universityof Guelph, spoke at
the technical update for Ontario
Master Gardeners in Burlington this
fall on the Mycorrhizea: symbiotic
association of fungus to plant roots.
Well that's a mouthful. But once he
got started he had those gardeners
listening intently.
The fungi we are familiar with
grow above ground or in the forests.
These species also form symbiotic
relationships and are part of a higher
order of fungi.
Dr. Peterson has spent years
studying healthy plant -fungus
relationships. Mycorrhizal fungi
have a mutualistic association
which enhances plant growth.
The relationships between fungi
and plants are so physically
interacted, so necessary, that their
28 THE RURAL VOICE
distinction becomes blurred.
There ate five types of
mycorrhizae fungi. They all basically
infect the roots of the plants with a
mass of fine fungal filaments. They
penetrate the cells of the host and
form a finely bunched network. The
mycelia of the fungi act as extended
roots for the plant, drawing in
nutrients at distances beyond those
reached by
the roots
and root
hairs, but
they do not
change the
shape or
structure
of the
root.
The
fungus
grows with
the cells of
the root. It
does not kill them
or parasitize them.
The fungi can't
photosynthesize their own food
so a remarkable exchange of nutrients
takes place — the plant gives
carbohydrates to the fungus and the
fungus gives proteins to the plant.
They absorb 20 to 30 per cent of a
host plant's sugar. This is not a one-
sided relationship. The fungi also
secrete organic acids that release
bound potassium, iron and
magnesium from the soil for the
plant to take in.
As my grandmother would say
that's nice but what does it mean?
Mycorrhizae, especially important in
nutrient -poor soils, aid in the
decomposition of litter and
movement of nutrients, especially
nitrogen and phosphorus, from the
soil into root tissue. Mycorrhizae
increase the ability of roots to absorb
nutrients, provide better absorption,
growth regulators, and mobilize
nutrients in infertile soil and make
available other nutrients bound up in
minerals. The study into this
relationship led to the no -till method
of working farmland. The tilling
breaks up the fine network of fungus
mycelium disrupting an important
feature in the soil structure. Why
disturb an element that improves with
age? As more time is spent studying
this relationship between plant and
fungi, more clues are unearthed (bad
pun) that can help us repair and
improve damaged lands.
Research has uncovered fungi that
bind heavy metals in the soil enabling
tree seedlings to establish in
polluted soil. This
association also protects
seedlings from root
pathogens. Eighty per
cent of the plants on this
earth share a mutualist
association with a fungi
species.
So how does this
equate in our gardens? I
have a garden that I have
not been "into" in three
years. I have been edging it
and pulling the occasional
weed but on the whole the soil
and perennials have been left
undisturbed. During the dry period it
held up remarkably well. I gave
credit to the the large trees for
sheltering the garden from the
drying sun of late afternoon, the
good soil, and the closeness of the
perennials. Mulch was a factor in
the beginning but had since
decomposed.
Now 1 know that mycorrhizae
fungi have had a hand in my garden
and have aided in keeping the plants
healthy. I have a greater appreciation
for the life teeming below the surface
of my garden. Mycorrhizae fungi are
another element that helps our
gardens to thrive.
As gardeners become more
aware of the complexities of the
soil they understand that gardening
is more than popping a pretty plant
into the ground with a handful of
chemical fertilizer. They are
responding to new ideas. The use
of mulch and organic fertilizers all
aid in the building of a strong soil
and in turn building a healthy web of
life. It is almost like learning how to
appreciate the world around us one
facet at a time.0