The fate of pesticides in soil

[Simon C]

I have been direct drilling since 2001 and using the Dale seedhawk drill since 2003 very sucessfully as a dryland operation on 550 mm rainfall.
Until 3 years ago we sprayed off all wheat stubble in the early winter to save moisture for the following spring crop of barley but we have developed some irrigation as a community scheme was coming past the gate. So we now sow annual ryegrass or triticale straight into the wheat stubble without any glyphosate as a cover crop come winterfeed crop for fattening lambs. This crop is then terminated with glyphosate early spring and sown into barley about a week to 10 days later but now have the same issue happening that Simon C has noticed. If the grass is hard grazed and sprayed short the issue is not quite so bad but still there and almost kills the barley if the grass or covercrops has any size to it.
It seems I am creating a huge issue and has me really questioning the use of glyphosate or cover crops. My dryland system still had an application of glyphosate before drilling in the spring but really the weeds were very small and thin so didn't notice the effect that I do now. I will try terminating the green more than six weeks earlier but it will effect the premium we received for our lamps so may make that operation a waste of time and money.
Just thought I would share this with you for the same reason Simon C and others have as I see the use of cover crops is growing and want you all to realise the expensive lessons this may create if not done properly.

@kiwi Thanks for this, it seems your experience is just the same as mine. I did a trial two years ago where I flailed off one tramline in a cover crop in the autumn to give the same effect as grazing. The peas were not quite as bad there as where the cover was left over winter, both being sprayed before drilling, but both bits looked worse and yielded less than the rest of the field that was burnt off in November.

I agree, we need to try some cover mixtures that have no known allelopathic effects on the following crop, then we could be sure about the glyphosate. Monsanto's answer to this is that the problem is being caused by breakdown chemicals of roots and tops (Two Simons), but I am not convinced.

 

[RushesToo]

@kiwi @Simon C On the tops of soil there are algae and cyanobacteria. They both photosynthesise and make amino acids. Glyphosate kills plants by inhibiting a plant enzyme that stops amino acids being created that are essential to plants.

It would be unsurprising if they inhibited or stopped the growth of these 2 minor constituents of soil ecology.

Where this would fit in with the overall health of the soil is worth seeking out - it might be easier to do further tests than try and seek scientific articles as to the mechanisms of Glyphosate, the biochemistry of algae and cyanobacteria, and the effect of removing one of both of these from the ecology.

I think this is called citizen science, empirical evidence or experience.

 

[Simon C]

@kiwi @Simon C On the tops of soil there are algae and cyanobacteria. They both photosynthesise and make amino acids. Glyphosate kills plants by inhibiting a plant enzyme that stops amino acids being created that are essential to plants.

It would be unsurprising if they inhibited or stopped the growth of these 2 minor constituents of soil ecology.

Where this would fit in with the overall health of the soil is worth seeking out - it might be easier to do further tests than try and seek scientific articles as to the mechanisms of Glyphosate, the biochemistry of algae and cyanobacteria, and the effect of removing one of both of these from the ecology.

I think this is called citizen science, empirical evidence or experience.

Yes, interesting. Glyphosate is also a powerful fungiside, so upsetting the balance as well.

 

[kiwi]

RushesToo I agree that it probably has an effect on soil ecology in terms of what you have outlined and as farmers we have to weigh up the benefits versus the cons of using the product. However why do we see such an effect from the use of certain cover crops after we have used glyphosate to kill off those covers off . As has been outlined is it the glyphosate or the combination of using the wrong cover crop prior to a certain cash crop that has almost killed the following cash crop. Or another issue is maybe the temporary tie up of nutrient the covercrop does before the release to the following cash crop. i haven't sown into the grass cover crop without using glyphosate so if I did I may get my answer but then their would be the issue of the grass competition taking the nutrient.

 

[Simon C]

What is baffling is that where glyphosate is sprayed onto bare soil or small young plants there is no noticeable effect, where as where there are over wintered plants, full size or grazed/ flailed, we get a problem. I see it mostly in peas, where I did a trial, you could see to the line between autumn and spring spraying, there was a lower plant population and they were a lighter shade of green. The lighter colour points to nutrient deficiency, whether that is from nutrients tied up in the growing plants or glyphosate interfering with the availability, I don't know.

 

[bactosoil]

Simon - what was glyphosate originally developed for ?

 

[SilliamWhale]

Simon - what was glyphosate originally developed for ?

Your going to tell us its a domestic cleaner or something now.

 

[SilliamWhale]

What is baffling is that where glyphosate is sprayed onto bare soil or small young plants there is no noticeable effect, where as where there are over wintered plants, full size or grazed/ flailed, we get a problem. I see it mostly in peas, where I did a trial, you could see to the line between autumn and spring spraying, there was a lower plant population and they were a lighter shade of green. The lighter colour points to nutrient deficiency, whether that is from nutrients tied up in the growing plants or glyphosate interfering with the availability, I don't know.

But this doesn't happen all of the time either. So it conditions must also have a bearing ie clive drills into and sprays into plenty of green

 

[rob1]

But this doesn't happen all of the time either. So it conditions must also have a bearing ie clive drills into and sprays into plenty of green

Maybe soil types have an effect

 

[SilliamWhale]

Maybe soil types have an effect

Maybe.

 

[bactosoil]

Glyphosate is the active ingredient of the herbicide Roundup, created in 1960 by Stauffer Chemicals, a US company with a business of cleaning mineral scales from industrial pipes and boilers. The mineral deposits (same as in electric kettles) are called scales, and the pipe cleaning chemicals are called decaling agents. Glyphosate was patented in 1964 in the US as a powerful and very broad spectrum decaling agent – a demineralizer.
and yes soil types will have an effect

 

[SilliamWhale]

Glyphosate is the active ingredient of the herbicide Roundup, created in 1960 by Stauffer Chemicals, a US company with a business of cleaning mineral scales from industrial pipes and boilers. The mineral deposits (same as in electric kettles) are called scales, and the pipe cleaning chemicals are called decaling agents. Glyphosate was patented in 1964 in the US as a powerful and very broad spectrum decaling agent – a demineralizer.
and yes soil types will have an effect

Is this info on google?

 

[Richard III]

Is this info on google?

https://en.wikipedia.org/wiki/Glyphosate#Discovery

 

[bactosoil]

U.S. patent number 3160632 A,

 

[SilliamWhale]

https://en.wikipedia.org/wiki/Glyphosate#Discovery

Yes thanks

 

[Simon C]

From the Wiki on Glyphosate
A 2009 study using a RoundUp formulation concluded absorption into plants delays subsequent soil degradation and can increase glyphosate persistence in soil from two to six times.[41]

The paper it refers too
http://www.sciencedirect.com/science/article/pii/S0045653509007528

 

[Feldspar]

Has anyone been / going to the NIAB winter conference yet? I'm hoping to go tomorrow and there's a talk from Bayer about biological pesticides. Will be interesting to see what they say.

 

[soilbug]

There is a lot of modern food, fruit and veg which are in reality "empty calories" - as in they do not contain the correct / full range of minerals.
Do you see much black grass on a correctly managed, 20 year experienced / professional organic farm? We are organic and some of our crops are considerably cleaner than our conventional neighbours, but we have plenty of other disasters happen.

I have enjoyed seeing this thread and will read with interest. I have very little knowledge, so can't really help, but am very interested.

Dont worry about lack of knowledge - we are all learning on the hoof when it comes to survival. Interested in your takeup of empty callories - most of everything is in the soil - you just need to find it and get the proportions balanced. I heard from a horse fanatic that a company Forageplus has a soil analysis service which tells you exactly how to do that - far better than the conventional fertiliser guys in white coats. I think human obesity and reduced ability to fight desease, including many metabolic disorders are encouraged by unbalanced food minerals, which also influence crop exposure to pests and deseases as well as yields. More learning to do!

 

[Feldspar]

Prompted by this thread: http://thefarmingforum.co.uk/index.php?threads/where-am-i-going-wrong.113898/#post-2351792, I think we need to seriously question the advantages of ferric phosphate over metaldehyde.

Copying:

This is a very interesting paper which actually finds that ferric phosphate is much more damaging to earthworms than metaldehyde:http://www.sciencedirect.com/science/article/pii/S092913930600031X.

Just ask yourself, what evidence have you seen personally that shows that ferric phosphate is any kinder to the soil biological environment. I haven't seen any.

 

[Feldspar]

Also, think about what evidence you have seen personally that ferric phosphate is more effective than metaldehyde from an unbiased source. This would seem to suggest that metaldehyde might be more effective: http://www.sciencedirect.com/science/article/pii/S026121940100120X.