Re: Glyphosate

Martin Brown wrote:
> neil@[EMAIL PROTECTED]
 wrote:
>> On 15 May, 18:57, "Emrys Davies" <m...@[EMAIL PROTECTED]
> wrote:
>>> I have read that glyphosate is deactivated when it comes into contact
>>> with the soil.   Does that mean that you can spray weeds with
glyphosate
>>> one week and then safely plant shrubs in the same area of land a few
>>> weeks later without there being any fears of the glyphosate which was
>>> originally used?
> 
> Short answer is Yes.
> 
>> Actually this is a slightly dodgy claim. It actually depends on the
>> soil. The glyphosate isn't destroyed on contact with the soil, which
>> is often how it gets repeated but it gets attached onto clay
>> particles. If you don't have clay particles because your soil is
>> primarily peat or sand then it can't happen.
> 
> For this to be a serious problem you have to be on wind sorted desert 
> sands or a perfect pure peat bog. Even a trace of fine clay will provide

> enough surface area to lock it down. Extreme cold and darkness will slow

> down the final decomposition too.
> 
>> Also this can't be as
>> instantaneous as the marketing speak seems to suggest. If it were it
>> would constitute a risk of fire or explosion. It will take a while
> 
> "A while" for physical adsorption onto clay is a fraction of a second on

> contact. It is the same sort of thing that makes activated charcoal take

> out impurities in tapwater and on about that sort of timescale.
> 
> If you want to test it spray some glyphosate onto your soil, take a 
> sample of the newly sprayed soil and add mustard & cress seeds. If they 
> grow OK then you have your answer (may fail on peat based composts).
> 
> To test the limits you could try planting mustard and cress and using 
> glyphosate spray immediately for their first watering. I don't know if 
> they can survive that since it will leave active residue on the seeds 
> surface.
>>
>> If your soil contains clay,as admittedly most soils do, then you are
>> probably OK a week later.
> 
> A trace of clay and the soil will lock up and deactivate the glyphosate.

> The molecules persist for a while but they cannot do anything.
> 
> Regards,
> Martin Brown
> ** Posted from http://www.teranews.com
**

So, do you reckon injection by syringe is an effective delivery method 
for glyphosphates? I'm thinking particularly of borage where I could lop 
off the top of the plant and inject into the main stem as I go. This 
would presumably not deliver much volume of liquid but at least it would 
be accurately placed. The roots are about a foot long so digging out 
isn't really an option.