D: On our Farm
Basics time we’re going to
talk about soil microbes. We
got a question on Ag PhD
Radio the other day about if
pesticides hurt soil
microbes or if they actually
help them. B: Well this is
an interesting debate
because I want you to think
about, “What are
pesticides?” If we talk
about herbicides, they kill
weeds right? So what are
soil microbes? They’re going
to be bacteria or fungi. So
is a herbicide going to kill
a bacteria or fungi? No. How
about an insecticide? No.
It’s just when we get down
to the fungicide. Will a
fungicide kill soil
bacteria? Well no, obviously
not. But would a fungicide
kill soil fungus? It’s
possible, but not every
fungicide kills every fungus
out there. D: No, and also
you have to kind of keep in
mind “where are we applying
this?” Like let’s say for
example you put a fungicide
right out there in-furrow
and you put it in a narrow
little strip. Is it going to
kill soil fungus right
around that? You bet it is.
But when you think about the
whole volume of your soil,
if we’re talking about one
narrow little strip out
there it’s not going to have
a great impact on your soil
fungus. Now, I try and to
equate it like this - if
you’re putting something out
to kill nematodes like many
farmers are doing this year
they’re dropping something
in the furrow on soybeans to
try and kill nematodes, they
aren’t going to make one bit
of difference for that whole
field, they’re just trying
to influence that seed zone
and that’s it. B: And these
products are short lived. So
a fungicide, we usually
figure 1-2 weeks residual,
that’s it. So if you do this
1 time per year is it really
that big of deal? Probably
not, especially when you
consider we’re not killing
that many strains of fungus
that are out there. But then
you start thinking about,
“Alright what’s really doing
some good for these bacteria
and fungi that are out
there?” Well one of the
biggest things that’s
helping them is when plants
kick sugars out into the
soil. When they kick more
sugars out then more
bacteria and fungus, it
multiplies. So I would say
using a pesticide to control
weeds, to kill insects, to
kill certain diseases -
that’s going to help make
the plant yield more which
means we’re probably going
to have a lot more root
mass, we’re going to kick
more sugars out, and I think
the soil population of
microbes is going to
increase. D: Well that’s an
interesting debate and
here’s one of the things.
Farmers really aren’t
measuring how many exact
microbes there are in the
soil and which types are out
there. B: No, but we know
they’re important. D: Well
we do know they’re
important, but we also know
there’s good ones and
there’s bad ones. B: Yeah.
D: And with many of the good
ones, farmers are starting
to put more biological or
natural type products in the
seed furrow and on the seed.
So putting the good strains
of fungus and the good
strains of bacteria right
there around your seed zone.
Well many of those strains
that farmers are putting out
have been thoroughly tested
to be able to be compatible
with fungicides that farmers
are using on the seed or in
the furrow. So we’re putting
fungus out that’s not going
to be killed by these very
specific fungicides that
we’re using to control
harmful diseases. B: Yep and
the main reason we wanted to
talk about this in our Farm
Basics time today is there
are a lot of people that
have many misconceptions
about pesticides. They think
the pesticides kill
everything in the world.
Well pesticides are very
focused, very specific, and
actually because of the use
of pesticides, in most
cases, we have healthier
food, we have a much more
abundant food supply, and we
have more soil microbes. D:
Impact on soils is very
important but so is weed
control. We’ll show you how
to stop this tough weed
later in the show.
