From: Barbara Lamar (barbaralamar@sanmarcos.net)
Date: Sat Aug 23 2003 - 14:14:49 MDT
Robert B wrote:
> I would like to see someone cite some Google references on the actual
> land area required to produce 2500 calories per day. (There seems
> to be a lot of hand waving going on here).
I responded with a reference to John Jeavons's book but forgot to mention my
own experience. I've found that in central Texas, a person can grow most of
the food needed by two people on 1/2 acre. This includes raising chickens
and rabbits (I've heard that guinea pigs and iguanas are also efficient meat
animals). I had to supplement what I grew with purchased grain and
occasionally some purchased beef and fish in order to get enough calories
and protein, and I've never personally seen anyone grow 100% of their food
on 1/2 acre, but I've heard people (including Jeavons) claim that it can be
done (in fact, I believe Jeavons claims it can be done on something like
1000 square feet per person). I initially had a pond stocked with perch,
bass and catfish, but we had a severe drought. The level of the pond got so
low that the great blue heron who dropped by every day for breakfast could
wade across the whole thing. If I'd had a well stocked pond or tank, I think
we probably could have gotten along without purchasing additional food.
Ponds are incredibly efficient food producers, since the entire volume is
productive, not just the surface area. However, by layering crops, you can
achieve something of the same effect on land (e.g. growing lettuce and other
somewhat shade tolerant vegetable crops under fruit trees and by training
vining plants such as squash and melon on trellises or fences).
Seed crops, although they have a high calorie content per pound of grain,
are not square foot efficient (although some grain crops, such as hemp,
might be square foot efficient when you consider the fiber value as well as
the value of the seed [the medicinal or recreational value of hemp leaves is
artificially high and would be negligible in the absence of drug laws]). One
of the most square foot efficient calorie crops here is the sweet potato
(especially if the vines are trained up a trellis or fence). Irish potatoes
aren't bad either, although we have a limited growing season -- gets too hot
from May on, and you can't set them out in the spring until February,
because they're frost sensitive. Mesquite beans are also efficient if you
consider that the roots of the mesquite tree fix atmospheric nitrogen in the
soil, and the leaves produce a very light shade, so you can grow other crops
directly underneath. Of course agribusiness farmers consider mesquite trees
to be the work of the devil, because they're almost impossible to kill, and
they interfere with the heavy equipment.
Barbara
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