permaculture

[paul wheaton <paul@richsoil.com>]

Wow, this is so crazy frustrating.  Ever since I posted that video, I
am getting swamped by folks that refuse to believe what is right in
front of their eyes.  And then they contact me to try to help me
understand why I am wrong.

I really don't think I can be more clear.  All I can do is repeat myself.

Here, I will try to say it a different way:

A bioassay can indicate certain levels of persistent herbicides.  So
if you do 100 bioassays with one type of compost, and then you do 100
bioassays with virgin topsoil with IDENTICAL FERTILITY, and you have a
50% death rate in the first set compared to the second set, then YES,
you most likely have a  persistent herbicide problem.

**BUT**

If you have 0% death rate, then you need to grow it out to adulthood.
If the samples in the first set are the same size, then your compost
is clean.

Here is the problem: nearly every bioassay I have ever seen done was flawed:

A)  There was no control at all.  If some peas germinate and grow,
this could indicate that there are persistent herbicides, but not
enough to kill the peas.  Just enough to stunt their growth - but you
have no control to compare to, so you don't know if the growth is
stunted.

B)  The control also has persitent herbicides, or the control is
crappy dirt.  The control must have soil that is equal in every way
with the exception that you KNOW for absolute fact that it contains no
persistent herbicides.  Getting this control soil can be very
challenging.  And I have yet to see ANYBODY doing a bioassay do this
step.

THEREFORE:  every bioassay I have ever seen first hand was useless.
Every single one.

Look at the raspberries in the video.  Note how the raspberries on the
left are NOT DEAD!  They are stunted.  Granted, there are far too many
variables here to qualify as a proper bio assay - but that is not what
she was attempting to do.  She ran out of contaminated material and
finshed the job with non-contaminated material.  She probably applied
the exact same amount both sides.  So this video shows typical
stunting of growth:  a level of persistent herbicide that doesn't
KILL, but stunts.

Summary:  nearly all commercial compost contains persistent herbicide.
 If you can get peas to grow in it, then you have demonstrated that
the level of persistent herbicide is not high enough to kill your
plants, but I would say that there is a 98% chance that it is in there
and WILL stunt your plants.  Plus there is a 98% chance that food you
eat from it WILL contain herbicides.   Rather than bother with a
bioassay, I recommend that you not use commercial compost.

A bioassay that would be worthwhile:  test 20 different commercial
composts and 20 different home made composts.  I think those results
will be fascinating.  In theory, a "professional" compost should
greatly outperform an "amateur" compost (I could fill a book talking
about this space).  But I suspect that the #15 home compost will come
out way ahead of the #1 commercial compost.

On Thu, Aug 19, 2010 at 12:01 PM, Jerome Rigot <jfrigot@gmail.com> wrote:
> Yes, but when doing a bioassay, one must use plants that are particularly
> susceptible to herbicides, particularly the herbicide tested.
>
> For example, for Clorpyralid, a persistent herbicide that can be found in
> municipal compost, the most sensitive plants are red clover, sunflower,
> peas, and tomato, which can then be used in bioassay (
> http://ohioline.osu.edu/aex-fact/0714.html).
>
> Peas, beans and tomatoes are particularly susceptible to aminopyralid. More
> details about this herbicide and of the type of bioassay to perform to test
> compost and even your soil for contamination:
> http://whatcom.wsu.edu/ag/aminopyralid/
>
> Jerome
>
>
>
> On Thu, Aug 19, 2010 at 10:11 AM, paul wheaton <paul@richsoil.com> wrote:
>
>> In the video, check out the raspberries.
>>
>> When you do a bioassay, you can get 100% germination in a soil that is
>> tainted with persistent herbicides.  There is just enough herbicides
>> to not kill, but to stunt the growth of your broadleaf plants.  So
>> your plants still take up the herbicide - they just don't die.  Your
>> food then contains herbicides.
>>
>> These types of herbicides generally have zero impact on germination.
>> Their mission is to weaken the plant - usually by emulating the plant
>> growth hormone auxin.
>>
>> Here is the blurb from the sales page for aminopyralid:  "translocates
>> throughout the entire plant and accumulating in meristematic tissues,
>> including the roots. It disrupts plant growth metabolic pathways
>> affecting the growth process of the plant."
>>
>>
>> On Wed, Aug 18, 2010 at 12:56 PM, Steven & Margaret Eisenhauer
>> <eisenhauerdesign@earthlink.net> wrote:
>> > Hello,
>> > My understanding is that a sprout test will indicate if a medium is good,
>> > bad or ugly. Herbicide residues will be indicated by fewer seeds
>> sprouting
>> > in the medium.
>> >
>> > -----Original Message-----
>> > From: permaculture-bounces@lists.ibiblio.org
>> > [mailto:permaculture-bounces@lists.ibiblio.org] On Behalf Of paul
>> wheaton
>> > Sent: Wednesday, August 18, 2010 10:56 AM
>> > To: permaculture
>> > Subject: Re: [permaculture] commercial compost and persistent herbicides
>> >
>> > This is an excellent test to see if the level of persistent herbicides
>> > is high enough to kill your plants.
>> >
>> > This test does very little to tell you if there is a level of
>> > persistent herbicides to stunt the growth of your plants or make them
>> > more susceptible to getting sick.
>> >
>> > On Wed, Aug 18, 2010 at 8:52 AM, Steven & Margaret Eisenhauer
>> > <eisenhauerdesign@earthlink.net> wrote:
>> >> Hello,
>> >> I have learned from various sources that one needs to look at every
>> >> amendment with caution.  To evaluate whether compost is healthy or bears
>> >> toxic residues one needs to do a sprout test.  Place seeds in between
>> wet
>> >> cloth or paper towel-unbleached and wetted with non chlorinated water as
>> >> your control and then plant the same type and number of seeds in the
>> > compost
>> >> in a flat and keep moist. Just compare your sprouting percentage in the
>> >> compost with the control and you will know whether the compost is clean
>> or
>> >> toxic.  The beauty of this test is that it only takes 3 - 5 days to
>> >> complete.
>> >>
>> >> Steven Eisenhauer
>> >>
>> >> -----Original Message-----
>> >> From: permaculture-bounces@lists.ibiblio.org
>> >> [mailto:permaculture-bounces@lists.ibiblio.org] On Behalf Of paul
>> wheaton
>> >> Sent: Tuesday, August 17, 2010 10:06 AM
>> >> To: permaculture
>> >> Subject: [permaculture] commercial compost and persistent herbicides
>> >>
>> >> Many people think their commercial compost is great because stuff is
>> >> doing better with it than their stuff did with cement-like dirt.  That
>> >> compost probably has persistent herbicides in it that is stunting
>> >> plant growth. But the only way to know for sure is to grow a bunch of
>> >> plants next to same species/variety plants that are grown in compost
>> >> that definitely doesn't have it.
>> >>
>> >> http://www.youtube.com/watch?v=GunQ9mB0ywU
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