On Thursday, May 20, 1999 1:44 PM, Manale.Andrew@epamail.epa.gov
> Re.: Dan Anderson's comment, "I especially had to stop to think because
> >most of the organic farmers I talk to *do* tend to import N in the form
> >off-farm compost, off-farm manure, etc. Their goal is always not to
> >to do so, but this goal seems difficult to achieve."
> Why should their goal be "not to have to import N onto their farm?" If
> have a reasonably productive system that results in ample N and P
> their farm as part of food or feed, then they must either import N onto
> farm--or include an N-fixing crop in their rotations--or suffer the
problem of N
> and P deficiency in their soils.
What is wrong with the second option, including an N-fixing crop in their
---Clearly nothing is "wrong with including and N-fixing crop in a rotation.
However, if the geographic boundary defining sustainability is drawn wider, then
the N could come necessarily not from the same field but another field or farm
within the geographic area. Expanding the options available to the individual
farmer improves his or her chances of maintaining "economic" sustainability.
The later in turn can lead to breakdown of the
> soils and the loss of organic matter. Why does sustainability have to
> defined in terms of the individual farm?
By definition, if the individual farm is not sustainable, then it will
decline, which means that its resources will be degraded, ending up as
sediment in somebody elses drinking water. I think that the individual
farm has to be sustainable. However, if you mean by sustainable, that the
individual farm has to have no net import of material, nutrients, etc., I
think you are right. It could be possible for a larger box to be drawn and
say that the N or P for that area is stable. However, if the box is drawn
in the right places you might have a situation where there is no net export
of N but that N is being concentrated in one area (within the watershed,
for instance) at a feedlot, but being depleted in the cropped fields
producing feed. Overall the N balance seems good, but I wouldn't say that
the crop production is sustainable, without major expense in non-renewable
fossil fuel to fix N from the air and apply it as fertilizer.
---I certainly agree with the importance of drawing the box in a manner to
maximize the greatest number of farms and area of land and seek to minimize if
not eliminate negative externalities for those outside the box. Where I may
disagree is with regard to fertilizer use. From a net energy and mass balance
perspective, I would argue that burning fossil fuel to fix N which is then used
to increase yield of crops which sequester carbon which adds to the health and
productivity of the soil and offsets any loss of fossil fuel by capturing energy
in the form of biomass makes sense. Not to say that our current system does it
that way. But it could.
Why can't it be defined in terms of
> the watershed or other geographic unit provided that inputs and outputs
> equilibrate? From an environmental perspective, it doesn't matter.
I think it does matter. The details are what is important. If there is no
recycling of nutrients within a watershed then one area ends up nutrient
poor and another overloaded, risking contamination. Sustainability is
much more than reducing inputs, although that can be part of it.
---If the nutrients are maldistributed within a watershed, then, of course, that
does matter from an environmental perspective. But I would argue that
sustainability drawn wider than an individual farm has to be drawn wide enough
to incorporate at least the smaller size watersheds and should not result in
negative externalities to neighboring or downstream watersheds.