[Market-farming] Controling quackgrass organically?
STEVE GILMAN
stevegilman at verizon.net
Wed Apr 2 07:37:11 EDT 2008
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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