It's instructive to remember that until the very recent past,
all humanity farmed "organically"--that is, without chemical
fertilizers or synthetic pesticides--AND we showed ourselves
quite capable of
degrading the environment without the aid of chemical
inputs. Using horses, oxen, hoes, goats, sheep, legislation
and various other non-chemical means, we managed to foist upon
the earth soil loss that only geological time can remedy.
A good book on this subject is Carter and Dale's Topsoil and
Civilization (Univ. of Okla. press).
The point, I believe, Mr. Hall was trying to make is that good
farming cannot be prescribed from afar. Good farming doesn't
come in a can or a list of prohibited and acceptable substances.
Good farming is committed and performed by good farmers. We
cannot legislate good farming!
More specifically, Mr. Hall was saying that reliance on culti-
vation for weed control opens up the soil to potential soil
erosion. In fact, it is almost impossible to leave the soil
surface without cover and not suffer some erosion. On the
other hand, an herbicide dessicated ground cover protects the
soil from erosion. You may think that such herbicide use
necessarily pollutes the environment, but it is not that simple.
Not all chemicals are created evil. It seems absurd that I
should even have to say it. Yes, there are some chemicals that
are so toxic that they should probably not even be produced--
and some of these are probably in the average home owners garage
or under their sink in the guise of cleaners, paints, varnishes,
etc. But the point is that the chemicals are "good" or "evil"
depending mostly on HOW they are used. The same goes for
tractors, tillers, hoes, horse-drawn cultivators, etc.
Some herbicides are more persistent in the environment than
others. Some are specific in their mode of action so that
their toxicity to non-target organisms is negligible. Some
(the pre-emergents) are toxic to emerging seedlings. Some
(the post-emergents) are toxic to existing vegetation. It
is specifically the judicious use of a post-emergent herbicide
that Mr. Hall was referring to. I'll give you an example
of what I consider an ecologically-responsible use of a
post-emergent herbicide. There is an herbicide on the market
called Scythe, and the active ingredient is pelargonic acid,
a naturally occuring acid (one of the fatty acids in soap) that
breaks down readily in the environment. The pelargonic acid
removes the waxy cuticle of leaves that it is sprayed on,
and the leaf dessicates. It does not affect woody tissue.
I use Scythe in my fruit tree nursery. I have very sandy soil
with low organic matter, and tillage further accelerates the
loss of organic matter. So I deliberately allow the weeds to grow
up to 6-8 inches before knocking them back with the Scythe
which leaves a soil-protecting mulch in place around my young
There are many other examples of organically-acceptable practices
that are not sustainable--use of plastic mulches, mining and use of
minerals like copper (as a fungicide), etc, etc. In short,
organic is not equal to sustainable