rmhoward at omninet.net.au
Mon Aug 6 04:06:52 EDT 2001
Toby Hemenway wrote:
> > Otherwise there's a lot of farmers who couldn't
> > undertake minimum tillage.
> The "beauty" of Roundup is that it is absorbed primarily via leaves, and
> almost not at all by roots; it also doesn't inhibit seed germination much.
> Thus there can be plenty present in the soil when the next crop is planted,
> with little effect on plant growth. So just because plants grow in a field
> formerly sprayed with Roundup doesn't mean that the glyphosate has broken
> down. Researchers found that in a field sprayed with Roundup and planted a
> year later with lettuce, the lettuce contained significant amounts of
> Roundup (don't make me dig up the paper to see what "significant" means!).
> So if you use Roundup on food crops, you're eating it.
Whoa - this does not make sense - Roundup is specifically toxic to Shikimic Acid
pathways in plants - how can any plant especially one largely comprised of leaves like
lettuce have 'significant' quantities of glyphosate in it's leaves and not be dead -
unless of course you sprayed it on to kill it - but this usually only happens with
> Soils with high organic matter and thus very active soil life will break
> down toxins quickly, but I suspect that if you use Roundup, you won't have
> good soil life for very long--it, and the surfactants it contains, are
> toxic to soil life (less so, of course than, say, diazinon). And I assume
> most people using Roundup are also using chemical fertilizers, thus they
> probably don't have high organic matter.
> > We should not jump to conclusions about the safety and hazard of Round up
> > based upon reports from Columbia
> The research I've seen, and that cited in the factsheet, all comes from
> legitimate, peer-reviewed scientific journals such as Pharmacology and
> Toxicology, Weed Science, Journal of Wildlife Management, etc. or from
> documents that Monsanto presented to the Feds.
I'm not in favour of Round Up but several of the links posted have referred to horror
stories about animals dying, skin diseases etc. in Colombia. Agent Orange was not the
same formulation as 2,4 _ D or 2,4,5_T sold over the counter in U.S.A. or Australia -
for one thing it had about 100 times more dioxin present. I don't know how toxic the
surfactants used in Columbia. Surfactants are detergents most are no more toxic than
the stuff under your average (non-green) kitchen sink. I wouldn't drink them either -
but the greatest environmental risk they pose is the phosphorus they contain - not
whether drinking surfactant is good for you. It's not. Big deal.
Round Up is deadly to frogs because of the surfactants in it.
The problem with surfactants is whether they break down. This has been known for a
long time. Early household detergents manufactured in the 50's and 60's contained
branched chain hydrocarbons which didn't break down -> lots of foam in the water.
Later compounds don't have branched chains. But neutral anion detergents which are in
common use today also present similar problems. It really does depend upon what the
specific detergent (surfactant) being used is and what the data on biodegradability
says and on what the by products are.
Soil bacteria and fungi will consume just about any source of carbon including
intractable waste like dioxins given the right environment.
Minimum tillage is far better for Oz soils than previous methods of crop growing. Of
course repeated application of glyphosate will affect the soil. If the same routine is
applied again and again in the same paddock. As far as the farmer is concerned what
s/he is likely to notice is not reduced fertility but Roundup resistant weeds
appearing. But this is an argument for crop rotation - and ultimately for leaving land
fallow once every few years. Of course this goes against the profit motive and that's
Weeds are just plants we haven't found a good use for. In the meantime whether I kill
them with a rotary hoe or chemical spray like round up the real question to ask is not
- how should I kill the weeds but how can i find a use for them. .
Regards Bob Howard
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