[APWG] Allelopathy knowledge can save a lot of timewhenweeding+restoring areas

Mon Aug 29 16:35:39 CDT 2011

All:

I appreciate Craig's reference, and would be interested in further details 
from anyone that would facilitate my updating. I'm far too lazy to try to 
catch up with all of the literature since the last millennium (and even then 
I didn't keep up with everything).

One thing straw can do is take nitrogen away from weeds; another is shade 
out emerging seedlings. But I am still curious about which particular 
chemicals are active against weeds, and which ones. I think we all have a 
responsibility to avoid grand proclamations and cherry-picking facts. I have 
made my share of broad claims, but have always been open to specific 
information that could prove them wrong.

Many years ago, I shredded up several acres of coastal chaparral and soil 
and applied it to a restoration site. I noticed that most weeds were quite 
stunted the first year. The first thing I thought of was allelopathy, and I 
visited C. H. Muller and asked him what caused the Salsola kali to be only a 
few inches high on the project while those within a couple of feet of them 
off the project were so big (2 or 3 feet or more). He didn't have an answer. 
I still don't. But I suspect nitrogen reduction caused by decay organisms 
working on the shredded vegetation mixed into the surface soil. The project 
went on, without any further fussing around, to be my first truly successful 
ecosystem restoration worthy of the name. So I'm always eager to learn 
something specific and well-researched in the area of allelopathy (whatever 
that is).

WT

----- Original Message ----- 
From: "Craig Dremann - Redwood City Seed Company" <Craig at astreet.com>
To: "Wayne Tyson" <landrest at cox.net>
Cc: "Ty Harrison" <tyju at xmission.com>; <apwg at lists.plantconservation.org>; 
<rwg at lists.plantconservation.org>
Sent: Monday, August 29, 2011 11:36 AM
Subject: Re: [APWG] Allelopathy knowledge can save a lot of 
timewhenweeding+restoring areas

>
> Dear Wayne and All,
>
> Probably the Journal of Chemical Ecology, including all of Dr. Liu's
> articles that he was the lead author or co-authored, would be a very good
> place to start for general information on the current research.
>
> However,  as an ecological restoration practitioner for native grassland
> restoration in California with all of our weed issues, by the 1990s had to
> spend the time and effort to invent a mathematical modeling for
> allelopathic interactions between plants, just to get our projects to work
> right the first time and every time.
>
> It is like knowing how much of an antibiotic, and what kind of antibiotic
> to add to a petri dish of pathogenic bacteria on a macroscopic
> scale--instead of your petri dish being 4 inches in diameter, it might be
> 600 acres, like you can see at http://www.ecoseeds.com/greatbasin.html
>
> Sincerely,  Craig Dremann (650) 325-7333
>
>> I'd like to be brought up to date on allelopathy research. "Back in my
>> day,"
>> there was C. H. Muller at UCSB and another guy at UCB who argued the
>> issues
>> back and forth a lot. Steve Lincoln did a master's on one of my very 
>> early
>> projects (1968-69), but didn't come to any conclusions that would be
>> useful
>> (in my view, at least) in ecosystem restoration practice. The problem 
>> then
>> was, as it often is in ecological research, too many variables. The
>> "chemicals" needed to be identified; perhaps they have been, and have 
>> been
>> demonstrated to be effective in lab tests. Muller noticed that, for
>> example,
>> where cows rolled in stands of black mustard, recruitment of indigenous
>> species would occur, so he had a graduate student roll around in some of
>> his
>> study plots. This might be analogous to laying the straw down, but I am
>> not
>> certain whether or not other factors (other than "chemicals") are
>> involved--or, for that matter, not a significant factor at all.
>>
>> WT
>>
>> "There are strange things done in the midnight sun, by the men who moil
>> for
>> gold . . . " --R. Service
>>
>> PS: Olivia, I have long been "unsubscribed" from rwg too, through no act
>> of
>> my own . . . I don't know that I need to be.
>>
>>
>> ----- Original Message -----
>> From: "Ty Harrison" <tyju at xmission.com>
>> To: "Craig Dremann - Redwood City Seed Company" <Craig at astreet.com>
>> Cc: <apwg at lists.plantconservation.org>; <rwg at lists.plantconservation.org>
>> Sent: Friday, August 26, 2011 10:53 PM
>> Subject: Re: [APWG] Allelopathy knowledge can save a lot of time
>> whenweeding+restoring areas
>>
>>
>>> Craig et al.:  It will be interesting to see the results of your Nasella
>>> pulchra straw mulch on the germination of the exotic annual weeds in
>>> Palo
>>> Alto.  Might I suggest scattering the straw prior to the soaking fall
>>> rains which trigger the annual's germination, rather than waiting for
>>> them
>>> to germinate and then applying the native grass straw mulch.  I think
>>> that
>>> allelochemics work in various ways (both germination inhibition as well
>>> as
>>> radicle growth inhibition) but I suspect that having the germinating
>>> weed
>>> seed exposed to the chemicals leached into the soil during the
>>> germination
>>> process may give better control.  This is like the classical alllopathic
>>> seed germination assay tests on moist filter paper but doing it in the
>>> soil (microbes and all).  Regards,  Ty Harrison
>>>
>>> ----- Original Message -----
>>> From: "Craig Dremann - Redwood City Seed Company" <Craig at astreet.com>
>>> To: "Craig Dremann - Redwood City Seed Company" <Craig at astreet.com>
>>> Cc: "Ty Harrison" <tyju at xmission.com>; "Craig Dremann - Redwood City
>>> Seed
>>> Company" <craig at astreet.com>; <ialm at erols.com>;
>>> <apwg at lists.plantconservation.org>; <rwg at lists.plantconservation.org>
>>> Sent: Saturday, August 20, 2011 10:34 AM
>>> Subject: Allelopathy knowledge can save a lot of time when
>>> weeding+restoring areas
>>>
>>>
>>>> Dear Ty and All,
>>>>
>>>> Knowing which native plant give off the strongest herbicides and which
>>>> are
>>>> the strongest weeds, can make you weeding life so much easier, and you
>>>> can
>>>> have the native plants help you as allies in your efforts.
>>>>
>>>> For example, yesterday I drove 400 miles round trip, just to pick up a
>>>> single bale of Stipa native grass straw, Nassella pulchra, whose straw
>>>> contains one of the strongest herbicides of our native grasses.  It was
>>>> like buying a 5 gallon bucket of Roundup in a bale.
>>>>
>>>> I am working on some test plots in the hills of Palo Alto, a beautiful
>>>> 70
>>>> acre canvas that is currently solid exotic grasses, and I want to see
>>>> what
>>>> can be done, to get it back to 99.5% native plant cover.
>>>>
>>>> So in test plots last year, I looked at the interaction between adding
>>>> fertilizers to modify the weed cover, and also adding California
>>>> poppies,
>>>> that you can see photos at http://www.ecoseeds.com/arastradero.html
>>>>
>>>> The ideal situation is if you are left with any weeds, you want to get
>>>> all
>>>> perennial rye plants, rather than any wild oats, ripgut, blando,
>>>> foxtails
>>>> or zorro grass, because the perennial rye has the weakest herbicide
>>>> effects of the six grasses.
>>>>
>>>> So what I am going to do, is wait until the first rains bring up the
>>>> weed
>>>> seeds, scatter a thin layer of Stipa straw on top of them, add poppy
>>>> seeds
>>>> plus fertilizers, and wait 3-4 months and see what I get, like baking a
>>>> cake but it takes a little longer.
>>>>
>>>> What I am hoping for is no foxtails, zorro, ripgut, blando, or wild
>>>> oats,
>>>> maybe <5% cover of perennial rye and 95% cover of the poppies.  Then
>>>> next
>>>> autumn, start sowing in the local native grass seeds, like the Stipa
>>>> itself.
>>>>
>>>> So I am going to give the weeds a double dose of allelopathy, first
>>>> with
>>>> the Stipa straw, then with the poppy plants producing it in their
>>>> roots--
>>>> especially effective against annual grasses.
>>>>
>>>> You can think about this allelopathy issue, as the land is one big
>>>> giant
>>>> petri dish.  And all the plants, all of the natives and all the weeds,
>>>> are
>>>> each giving off herbicide-like chemicals like antibiotics at a greater
>>>> or
>>>> less amount.  We need to go out and see what the relationships are, and
>>>> use them to our advantage.
>>>>
>>>> Many of our Endanagered plant and animal species in the West are
>>>> grassland
>>>> species, and knowing which weeds are the most toxic against the native
>>>> plants, and knowing which native plants are the strongest against the
>>>> weeds, can help save a lot of time and effort when managing or
>>>> recovering
>>>> those species.
>>>>
>>>> Sincerely,  Craig Dremann (650) 325-7333
>>>>
>>>>
>>>>
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>>>
>>>
>>>
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>>
>>
>>
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>>
>> Disclaimer
>> Any requests, advice or opinions posted to this list reflect ONLY the
>> opinion of the individual posting the message.
>>
>
>
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