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  • From: STEVE GILMAN <stevegilman AT verizon.net>
  • To: market-farming AT lists.ibiblio.org
  • Subject: Re: [Market-farming] Controling quackgrass organically?
  • Date: Wed, 2 Apr 2008 07:37:11 -0400

Hi Martin,
I'm fortunate to be part of a SARE Ecological Weed Management project led by Dr Charles Mohler at Cornell. What's below is small part of a presentation I gave at the Long Island Ag Forum this winter -- and I'll have an expanded version that I'm presenting at this summer's NOFA Conference in August in Mass.

A comprehensive manual is slated to be published in late 2009 by SAN after extensive review from workshop presentations -- its working title is: “Manage Weeds on Your Farm: A Guide to Ecological Strategies” and is co-authored with Toni DiTommaso, who is also in the department of Crop and Soil Sciences at Cornell University. An entire section is concerned with how to think about weeds, along with successful cultural management practices of how to deal with them.

At root, an organic-ecological approach to managing weeds uses an understanding of the biology of weeds to outsmart them by exploiting their weaknesses. This is therefore an information-rich rather than an input-intensive approach. Some of the precepts are quite easily grasped, while the deeper-down management paradigm shift may require some considerable between-the-ears adjustments. Also, this understanding may help farmers to come up with further innovative weed control strategies and practices.

-- Wandering perennials such as quack grass and hedge bindweed are often the hardest type to control. They spread by underground rhizomes or horizontal roots, sending up daughter plants above ground. Because they have the ability to renew themselves vegetatively as well as produce windborne seed they can persist for years, their clones becoming nearly immortal if left to their own devices.

Perennial weeds that propagate vegetatively require vastly different strategies. Some perennial weeds may persist for years and years because they have buds on their roots or underground stems that sprout when the plant is damaged. The rhizomes of wandering perennials such as quackgrass are simply thickened stems that store nutrients horizontally underground, although they look more like roots than stems.

Roots and rhizomes form buds at regular intervals that remain dormant due to hormones that are released from the growing tip of the underground stems. As the distance between the buds and the growing tip grows longer, the hormone concentration diminishes so that the previously suppressed buds sprout and become a new above-ground shoot. As anyone who has tried to tackle an area of quackgrass knows – initial tillage a good way to rapidly increase the number of shoots and thereby spread the plant.

That’s because the cutting up of the roots and rhizomes by tillage releases the buds from their hormonal suppression, causing them to sprout. But the sprouts have less nutrient reserves to draw upon from the segmented underground stems, and their growth is less vigorous. And this is the key to the control of wandering perennials. The ideal point to impact the plant is when the new emerging shoot has used up most of the reserves of the original rhizome fragment – and before the shoot forms new storage roots or rhizomes. With quack grass the minimum size when the rhizome segment is at its weakest is usually reached when the shoot has formed three leaves – and that’s the key time for another round of tillage to finally kill the plant.

Hope this helps,
Steve
Ruckytucks Farm





From: market-farming-bounces AT lists.ibiblio.org
[mailto:market-farming-bounces AT lists.ibiblio.org] On Behalf Of Glen Eco Farm
Sent: Tuesday, April 01, 2008 9:20 PM
To: Market Farming
Subject: [Market-farming] Controling quackgrass organically?



I know this question has probably been asked several times before on this
list but i am too busy (lazy?) to go dig it out of the archives so I am
going to ask it again. Just what are certified organic farmers doing to
control quackgrass?

I've been spot spraying with glyphosate for a number of years now and I may
as well quit because it isn't working. The stuff just keeps popping up all
over the place. I lay out my crop ground in alternating strips with grass
so I can have a form of crop--noncrop rotation and soil building with grass,
legumes, and various perrenial weeds growing in the non crop areas. I keep
these areas mowed and rotate them back to crop strips every couple of years.

I am resolving this year to try and be a better boy by repenting of some of
my past sins of using forbidden materials (even on a limited basis) such as
glysophate (aka Roundup), some salt based fertilizers (side dressed or
foliar sprayed), and some broad spectrum insecticides and fungicides for the
worst infestations. It's kind of like drinking beer. One can easily
justify drinking a little every now and then--after all beer is not that
high in alcohol and it won't hurt you if you don't overdo it--right?
Trouble is after awhile you find your self drinking more and more. If you
really want to play it safe just stay away from the stuff!

Of course I can go out and diligently dig it up--or cover it up with several
layers of black plastic--yeah right! It's really getting itself established
in the current noncrop strips and is going to be a real mess in a couple of
years when I try to rotate it back to crop strips. The only thing I know to
try right now is to get a better chisel plow, rip the hell out of the
infested spots, and hope for another drought this summer. If that doesn't
work I guess the next thing will be to look for another farm.

Marlin Burkholder
Shenandoah Valley
Virginia



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