Topic: PSD Update on Testing For the Presence of Aminopyralid

[ceres]

PSD issued an update yesgterday:

http://www.pesticides.gov.uk/garden.asp?id=2529

"It has been difficult to find examples of damage where details of the source of the manure and how much might have been derived from treated grassland are known with any certainty. In the first example that went some way to meeting these criteria, the manure had been supplied over a number of years by a single farmer. Dates are not precise but after purchasing in January 2008 and digging in or rotavating during February-March, various crops were planted in April. Samples of the remaining manure, treated soil, and affected potatoes and tomatoes were taken in July and analysed by the government’s Central Science Laboratory.

Crop samples of potatoes and tomatoes contained trace amounts of aminopyralid. The levels were below the Limit of Quantification (LOQ) of 0.02 mg per kilogram. The LOQ is the lowest level at which quantifiable residues can be measured.

The unused manure sampled in January still had trace residues below the LOQ.

It was not possible to find aminopyralid in the treated soil taken. This reflects the bacterial decomposition that begins to act on the pesticide after free aminopyralid is released from plant material in the manure in the first few weeks after digging in."

[Trevor_D]

So does that mean that the advice to dig or rotovate affected manure is actually sound and the best way of dealing with the problem?

Or does it mean that nothing serious actually happened at all and that we should go home and stop worrying??

(They are going to do more than one test, aren't they?)

[asbean]

Find it hard to believe that they had difficulty in finding examples.  A lot of people still don't even know about the problem, I was asked for more info only last week by someone on another plot who gets manure locally who's had dying crops, it's going to continue for ages.

So if the crop samples they took had traces in them, even so low that it doesn't hit their scale, and is therefore unimportant, does that make it OK and the crops can then be considered "organic"?  I think not.

[ceres]

I think what they were trying to do was conclusively prove the link between aminopyralid being sprayed and damaged crops.  So they had to find examples where a farmer would confirm that he had sprayed with aminopyralid and that he fed the sprayed material to his animals and that the resulting manure was the manure that ended up damaging crops.  That farmer would effectively be owning up to breaching the Pesticides Regulations and therefore breaking the law.

I don't really think that finding only trace amounts is the issue.  The amounts, however small, have got into the food chain which wasn't supposed to happen.  The trace amounts have still caused damage.  So I doubt if Dow are getting any comfort from the tests.  On the contrary, the link has now been proven.

I think that not being able to find it in the soil is good news so digging over/rotovating affected areas is good advice. 

[Eristic]

I think that not being able to find it in the soil is good news so digging over/rotovating affected areas is good advice. 

No! This is bad. The reason it is not in the soil is because it has washed out into the water courses, or by spreading it over a wide area it simply becomes too small for scientists to bother measuring.

There is no proof of the stuff biodegrading but lots of proof of the chemical migrating to neighboring plots.

[ceres]

I think that not being able to find it in the soil is good news so digging over/rotovating affected areas is good advice. 

No! This is bad. The reason it is not in the soil is because it has washed out into the water courses, or by spreading it over a wide area it simply becomes too small for scientists to bother measuring.

There is no proof of the stuff biodegrading but lots of proof of the chemical migrating to neighboring plots.

Can you offer some evidence please?

[growmore]

Nice one ceres for following this one up..
So despite it being below the  Limit of Quantification (LOQ) of 0.02 mg per kilogram, which sounds as though this is the lowest level they can measure.
We still don't know if  the areas treated with the contaminated manure may still have the same effects on our broadleafed crops  next year as it did this year... 
Or have I understood it wrong?

[ceres]

hi growmore
I think all they proved was that weedkiller in manure causes damage.  I don't think there is any way of measuring or working out how lfor ong the weedkiller might still be causing damage after applying the manure.  For the manure to be neutralised, the sprayed plant material needs to completely rot away and then the soil organisms break the aminopyralid down into harmless compounds in around 3 weeks.  It's the rotting away part that is unquantifiable as it depends on too many variables - temperature, moisture content, soil type etc. etc.  Trevor_D's experience is that they still have some damage in year 2.  But the expert advice on digging over/rotovating affected areas as many times as possible over the winter seems to be the best hope for minimising any damage in year 2.

[growmore]

Hi ceres, Many thanks.

[tonybloke]

I think " if in doubt, plant a squash in your manure heap" this should let you know if it's o.k. to spread on your plot next year.? (please correct me if that's bad advice)
Tony

[ceres]

Hi Tony
Squashes aren't one of the plants sensitive to aminopyralid so even if the weedkiller was there, they may not show damage. 

[tonybloke]

Ah!