>The secret to reducing pesticides in no-till is cover crops, crop rotation,
>long-term no-tillage, and to do your own spraying. I've seen cover crop
trials
>that still gave weed control effects 2 years later. I've considered growing
>soybeans w/o herbicides by growing a good stand of rye, rolling it a couple
>times with the rolling stalk chopper and no-tilling them. Organic $22 food
grade
>beans IS attractive! Right now Rodale Institute has a food grade bean
trial on
>our farm so I'm getting a good look at the varieties. I used very little
>herbicide in the trail plot and the beans are perfectly clean -which I don't
>need to have. Of course we all know the benefits of crop rotation. Long term
>no-tillage helps in reducing the "planting" of seeds with tillage. I've
found
>my worst weed problems are when I'm weaning a field off tillage. Since I
do my
>own spraying I treat each field with it's own perscription. Some areas don't
>need any pesticides and I shut the sprayer off. I call this "low tech"
precision
>farming.
>
Steve's observation points to a key feature of this issue/controversy. We
tend to cast things in terms of "weed control" and end up "fighting" weeds
by any means at our disposal. This logic inevitably ends up with herbicides
mainly because they are less work. But if we step back from the daily
grind of "fighting weeds" a bit then we have to realize that the real issue
is ecological succesion, or in plain language, *which* weeds are growing
there? Succession is the change over time in soil and plants on a given
parcel. One season's vegetation prepares the soil for the next season's
vegetation and there is a gradual change over time. In farming, it depends
primarily on our cultivation techniques, including intercropping, and "weed
control". If we plant a cover crop one year that entirely covers the soil
and then don't do anything and just watch what comes up next year (an
interesting experiment) we will notice that the composition of the "weed"
patch is often dramatically different from the pre-cover crop field. If we
spray Round-up and do the same thing we will observe a very different weed
patch the next year. Some weed patches are much nicer to farm with than
others and these tend to be the weed patches that result from cover crop
management--at least that is my experience from observing this in the
Mexican tropics for many years. The purpose of cover crops, no till and
organic weed management is not to eliminate weeds or to reduce herbicide
use but to direct ecological succession to a desirable state. Our
expereince is that herbicides, even in "reduced" amounts, are totally
counterproductive to this effort as they provoke the presence of weeds that
are difficult to control. Thus totally eliminating any herbicide use as
soon as possible (or avoiding it to begin with) is definitely the best
policy. This sometimes involves work. Herbicides just make noise and
prolong the process of getting ecological succession on our fields under
control. In this, we have found that strict organic techniques are far
superior to hybrid "no-till". Conditions vary and history of use makes a
difference, but we have found this conclusion to be pretty universally
valid--but, I repeat, it takes work, no way around it.
Ronald Nigh
Dana, A.C.
Mexico, D.F. & San Cristóbal de Las Casas, Chiapas
Tel. y FAX 525-666-73-66 (DF)
529-678-72-15 (Chiapas)
danamex@mail.internet.com.mx
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