FUNGUS COULD CUT CORN FERTILIZER USE

By TOM BUTTON

Corn growers may soon start planting inoculant
along with their seed so they can produce the same
high yields with less fertilizer.
A federal research team at Ottawa working with a
prototype inoculant is finding it increases yields
an average 20 per cent over a variety of soil and
management conditions.
Soybean growers already inoculate their crops, but
there are important differences. The corn inoculant
is made up of fungi, not rhizobia bacteria. And the
job of the corn inoculant isn't to give the crop a
free source of atmospheric nitrogen: it's to make
the corn a lot more efficient at using nutrients
already in the soil.
The underground linkages between corn roots and the
fungi are also complex, and more must be learned,
says Sherman Nelson, scientist for the agriculture
department's Centre for Land and Biological
Resource Research.
Researchers have learned that soil fungi infect
corn roots in a way that benefits both the corn and
the fungus. The fungi get access to nutrients from
the corn, which accesses nutrients, including
phosphorus and nitrogen, that fungi take up from
the soil with their extensive root-like systems.
Some fungi already exist in virtually all corn
soil, but by adding more and different fungi as an
inoculant in the seed furrow, researchers hope
farmers will be able to manage the microbes for top
yields with lower, more environmentally-safe
fertilizer rates.
With early trials showing a 20-per-cent yield
increase in inoculated plots, Nelson and the Ottawa
team are planning more tests to confirm the yield
benefits across more field conditions.
"We need to get the inoculant into the hands of the
farmers, and we need them to be trying it on their
soils and with their farm practices," Nelson says.
"If we get the right results, we need to consider
how to commercialize the system."
Other tests are aimed at finding out whether the
inoculant works consistently, whether it carries
over from one year to the next, and whether it
works as well in a second year as it does in the
first.
Researchers are also looking at hybrid effects.
Tests show that when exposed to the same level of
fungus, the amount of infected root can range from
eight to 80 per cent, because of hybrid genetics.
But simple infection isn't enough, Nelson says.
Researchers are also learning that some hybrids are
more effective at tapping the nutrient flow from
the fungi, so two hybrids with the same infection
rate may have different yield results.
Researchers also want to learn more about how
farming practices affect the fungi. Tests suggest
that no-till fosters the production of fungi, while
populations of the fungi are lower in heavily
cultivated soils.
"We have seen some encouraging results, but it's a
little too early to predict whether inoculating
will become part of our corn production systems in
the years ahead," Nelson says. "As scientists, we
are very cautious," he says, although the centre
has started discussions aimed at finding
private-sector partners to help in the possible
development of farm-level inoculation.
Nelson thinks farmers would use their planters to
apply the dry inoculant in the seed furrow, rather
than directly on the seed, as with soybean
inoculant. "The quantities are too large to be
applied on the seed," he says.
"We think the main benefit of inoculation will be
to improve production efficiencies."  Our hope is
that with the help of an inoculant, farmers will be
able to maintain their yields even though they cut
back on their fertilizer." 

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