"Neil Jones" wrote in message
Martin Brown wrote:
In message , Neil Jones
You are being hoisted on your own petard. You continually repeat a
statement which is OBVIOUSLY not truthfull. Glyphosate is not
necessarily inactivated on contact with soil. There are several
studies which show this and I have posted references before. You don't
need studies to show this because it is an OBVIOUS conclusion from the
nature of the chemistry involved.
Whilst there are some "soils" where glyphosate is not immediately bound
up. They are in general so utterly infertile that you aren't likely to
be using weedkiller on them in the first place.
Glyphosate and for that matter several other common weedkillers are very
tightly bound to clays and/or organic material in soils on first contact
and so physically deactivated. The destruction of the molecule takes
longer but the stuff is very effectively tied up on hitting the ground.
I am afraid you are quite wrong on your science. You appear not to have
understanding of the processes involved. If it were to be as tightly
as you claim then id would not be degrated. Basically it appears that it
bound rather as phosphate is by adsorption onto the surface of certain
In fact it pops on and off and the soil doesn't have to be that poor for
of growth to be observed.
This is what just one study says.
" Although glyphosate is commonly thought to exhibit no residual
activity, recent field work with tomatoes has shown that phytoactive
residues can persist, at least in sandy soils. Adsorption may also be
low, and phytoactivity high, in soils with a low unoccupied P-sorption
capacity. This paper reports experiments designed to re-assess the
threat of glyphosate residues to crop plants.
So it may depend on the amount of phosphate present. Very fertile soils
may have a lot and therefore it is not adsorbed.
I bet the effect was at a trivial level, otherwise, since glyphosate is used
on a truly vast scale, its deleterious effects would have made themselves
visible on a macroscopic scale, via, for example, reduced crop sizes.