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

[Michael Schenk]

I have several things to add:

One, I have been using Virginia wild rye and little bluestem (and other Eastern native grasses) against West Virginia stiltgrass for several years. Where the rye and bluestem get established, the stilt grass does not become dominant, and even becomes sparse or rare. This has saved me enormous amounts of work, since I use mechanical methods, not herbicides. 
Two, the selection and use of individual chemicals which are effective in allelopathy would miss the potential synergistic effects of using the whole plant. This is analogous to using a single chemical extract from medicinal plants, as opposed to getting the benefit of the suite of compounds (and their interactions) available in the plant.
Three, I suspect that there is resource competition that favors the perennial native grasses over the weak root system of the stiltgrass. Shoots springing from perennial roots would likely have a competitive advantage, as well.

In short, I think we get more bang for the buck using native grass seed rather than manufactured allelopathic compounds as far as fighting invasives on a large scale goes. I like the idea of paying growers, not factories. However, for a general organic weed killer, the compounds might be useful, so research in that field would be good.

My $0.02 worth,
Michael Schenk

-----Original Message-----
>From: Craig Dremann - Redwood City Seed Company <Craig at astreet.com>
>Sent: Sep 2, 2011 1:55 PM
>To: apwg at lists.plantconservation.org, rwg at lists.plantconservation.org
>Subject: [APWG] Allelopathy knowledge can save time when weeding+restoring	areas
>
>Dear All,
>
>Thanks for your email.  I got a couple of offline questions about knowing
>the id of the active herbicide chemicals in the plants, and why use 2
>inches of the Stipa straw?  I am posting my reply, as it might be of
>interest to all:
>
>Even if we do not know exactly what chemicals in these plants are working
>against the weeds, if we figure out how to use them to our advantage,
>perhaps they could save a huge amount of time and labor for all of our
>weed management or restoration project?
>
>If we think of these chemicals as antibiotics, and we are applying them to
>a macroscopic petri dish, then they could be visualized that way.
>
>Instead of waiting for someone to id the chemicals that were active before
>I could use them,  I thought it was more important to invent a method to
>measure the chemical effects of one plant against another, and give each
>plant a number 1-100 to indicate their power?
>
>Then it becomes like a poker game, where a 8 beats a 3 for example.
>
>I am using 2 inches of Stipa mulch, for its long lasting effect at the
>site, because of the multi-layered dormant weed grass seeds in the soil.
>
>On the site in Palo Alto, there is a 150 year history of the introduction
>of weed grasses buried in layers like an archaeological site, with the
>most dominant grass suppressing the germination of the dormant seeds of
>the next, and so forth, and there are at least 5 layers out there.
>
>So let's say from the pictures at http://www.ecoseeds.com/arastradero.html
>that wild oats is the most dominant layer, so when you suppress the wild
>oat seeds from germinating, then the ripgut grass seeds get to germinate. 
>Then when you suppress the ripgut, the Blando brome is allowed to
>germinate.
>
>When you suppress the Blando, the Perennial ryegrass may by your final
>layer of weed grasses.  But wait--you are not done yet with the dormant
>weed seeds!
>
>Now all the different annual and biennial forb weeds that were suppressed
>by all the grasses will want their turn to sprout, once the suppression of
>the allelochemicals of the grasses has been released.
>
>Before I begin any large scale project, I want to know accurately what the
>allelochemical strength for each weed species and each native species on
>the site.  Then as the team captain for the natives,  I know which natives
>I should pick for my team to beat the exotics.
>
>For the cheatgrass, just planting back the local native grasses will
>permanently take care of that weed nicely, as you can see my photos from
>the 600 acres that were planted in the Great Basin at
>http://www.ecoseeds.com/greatbasin.html
>
>I am going to look forward to others reading these two lists, who will
>experiment with this idea over the next year, and we should share our
>results next summer, and see what strong allelopathic native and exotic
>plants we have come up with in the different parts of the country?
>
>Sincerely,  Craig Dremann (650) 325-7333
>
>
>
>
>
>
>_______________________________________________
>PCA's Alien Plant Working Group mailing list
>APWG at lists.plantconservation.org
>http://lists.plantconservation.org/mailman/listinfo/apwg_lists.plantconservation.org
>
>Disclaimer
>Any requests, advice or opinions posted to this list reflect ONLY the opinion of the individual posting the message.