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[compost_tea] Re: in-furrow soil insect prevention?
Thanks, Elaine. I will study this more using the sites you
recommended. I got this idea from a consultant in Canada, but he
wouldn't give me the rates, something about it being propriatary
information. Jerry
--- In compost_tea@yahoogroups.com, soilfoodweb@a... wrote:
> Why would wet sugar make a hostile environment for any insect?
>
> Consider what we know about sugar, kelp and lignite added to soil.
Is this a sufficient set of conditions to have teh desired result?
>
> No. These additions will not work under certain conditions. When
will addition of these things be sufficient to have the desired
effect? You need to understand something more than just adding
sugar, kelp and lignite.
>
> Do you have to add all three? And how much? You need to understand
WHY they MAY have an effect. What are the conditions that allow for
success, what conditions mean no benefit should be expected?
>
> Simple sugars are bacterial foods. As bacteria grow using the
excess simple carbon that was added, they suck up all the other
nutrients, like N, P, S, etc. You get an area where anything else
needing these nutrients is SOL. Bacteria win in competition with
anything else when they have enough simple sugar. Of course, you
have to have decent bacteria, so an inoculum is a good idea (as in
good aerobic compost), especially in chemically treated soils.
>
> Add enough sugar, you'll kill your plants simply because there are
no nutrients left for them to grow. What is the right amount of
sugar? Kelp is added to provide nutrients, but what's the right
balance?
>
> The nutrients in kelp supply which set of organisms with
nutrients? The bacteria and fungi. Plants can't access the
nutrients in kelp material. How do you get the nutrients in kelp
into a plant available form? You have to have the protozoa,
nematodes and microarthropods present to allow that to happen.
What's the right balance of bacteria and fungi, and protozoa,
nematodes and arths?
>
> Where can you find out this information? Soil Foodweb. The Soil
Ecology Society. Applied Soil Ecology. Biology and Fertility of
Soils. Univ of Georgia's Soil Ecology program.
>
> But think about this - if you add enough sugar, the soil in these
areas will go anaerobic as the bacteria grow and use up the oxygen.
>
> If you have wire worm, cut worm or other obnoxious pests, you might
be able to drive them away, since these pests need some oxygen. But
then the soil is anaerobic. Bad news for seed germination and root
growth.
>
> Will the soil stay anaerobic? Depends on the health of your soil.
If you have good soil strucutre, then life will be ok, as the oxygen
returns, the normal set of organisms will revive and life goes on
only a little hammered.
>
> But what if you don't have good soil structure? Then your seed is
in trouble. You might even say, "See, the cut worms and grubs are
hurting the seeds" when in fact the pests have been driven away from
the seed by the anaerobic conditions and aren't responsible for this
damage.
>
> What if the soil is anaerobic only in the zone you added the
sugars? Then the pests just go a little ways and hang out until the
root arrives. And the root may be weakened from the anaerobic
conditions.
>
> These pests also like reduced oxygen conditions (how reduced?
Probably in the range of 5 to 6 ppm, but I don't know of any hard
data on this - does anyone?). Why do the pests like the reduced
oxygen conditions?
>
> The bacteria that grow in aerobic conditions make the environment
unpleasant for these pests. If you are careful to add only enough
sugar to help the beneficial bacteria, soil structure will be
improved as these bacteria make glues, form microaggregates, and help
oxygen diffuse more rapidly into the soil. The critters that eat the
pests move back into the soil.
> Get some fungal and bacterial species that prey on the pests to
grow - but they require aerobic conditions, or at least not-reduced-
to less than 6 ppm oxygen.
>
> What does the kelp do? Micronutrients, some plant growth factors
(which the bacteria and fungi consume quite rapidly, probably long
before the factors make it to the root. If the soil is healthy, the
bacteria and fungi that these things grow are probably the real
answer to why kelp growth factors work well). Kelp also contains all
the foods normally in plant cytoplasm, and so good growth foods for
bacteria and fungi. Probably more bacteria than fungi, but some
really great fungi. So, the nutrients are made plant-available
because the biology is functioning.
>
> Lignite is a source of very complex foods for the fungi. Only
after fungal enzymes start chewing on the lignite will any bacterial
food be released. Which fungi and bacteria grow on these materials?
There's a whole area of research that needs to be addressed, and
people are addressing it. SFI is part of that work.
>
> So, again, is too much of these foods are added in, the soil can be
driven anaerobic as the organisms start to grow faster than oxygen
can diffuse into the soil. If the soil has good structure, then this
problem is less likely to occur.
>
> I had to laugh when I read something the other day that said that
molasses or sugar causes root-feeding nematodes to explode. Really?
And what's the mechanism there? Root-feeding nematodes have no
mechanism to take-up sugars from the soil solution. They eat plant
cellular liquid. Sap-suckers, if you will. They like reduced oxygen
conditions. They have thick cuticles that prevent bacteria from
having much affect on them. Could root-feeders get drunk on the
alcohol produced when lots of sugar is added and the bacteria and
fungi (yeasts) grow? Maybe that's the mechanism. But some data on
that would be useful, because then you would need to know that sugar
addition only works on root-feeders when the soil is badly
compacted.
>
> Please, make sure you understand that I'm trying to point out lack
of knowledge here - do not go around saying that Elaine said alcohol
kills root-feeders. We don't know that.
>
> I'm saying we need to know the mechanism by which SOMETIMES
molasses addition reduces pests. It does not work in all cases, and
until we understand WHY it works sometimes, we will never be able to
predict when additions will work and when they will not.
>
> It isn't appropriate to claim that sugar kills pests, because there
are many conditions where it doesn't work. When does it work? We
need to understand these things first, or these statements lead
people to believe that organic ag, or sustainable ag, does not work.
>
> So, to understand when this group of soil amendments have an effect
on soil pests, you need to understand the life in your soil.
>
> Elaine Ingham
> President, Soil Foodweb Inc.
> SFI Corvallis, OR
> SFI Port Jefferson, NY
> SFI Lismore, NSW, Australia
> SFI Hilversum, The Netherlands
> SFI Cambridge, New Zealand
> www.soilfoodweb.com
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