[APWG] Allelopathy knowledge can save a lot of time when weeding+restoring areas

[Ty Harrison]

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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