FNRJH@ALASKA.BITNET (Robert Jessie Hale III) (03/11/89)
As a reminder I will be off the computer for two weeks. March 11-27.
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#24 ACAD3A::FSRRC Thu 09 Mar 1989 23:35 ( 145)
March 8, 1989
ISECCo PROJECT UPDATE #6: Crops cycling.
Background:
Dinner in a small, closed ecology is not a matter of simply choosing
what you want to eat just before you begin cooking, or even a day or two
before: it must be planned months in advance. The diet must be pre-
calculated months in advance of consumption for the food to be eatten
must be grown first. I doubt it will have to be QUITE this strict; if
you could not stand to have carrots & fish for dinner you could get away
with substituting cabbage & worms--but the carrots & fish would have to
be eatten the next night, or shortly thereafter for in a closed ecology
all food must be cycled (and the occupant is the 'cycler'!).
Calculations involve the time required for the desired crop to grow,
quantity needed, calories required and nutritional data. Naturally if
you want to have carrots for dinner a month from now you better already
have them in the ground or you won't be able to harvest them on the
desired date. Quantity needed for each crop is determined by a balance
between the calorie requirement, the nutrient requirement and what else
is to be eatten. Calories are easy to look up, as is nutritional
information. These calculations may or may not be performed in actual
biosphere operation--since we will be gradually building up the ecosystem
we should be able to maintain a balanced diet by careful attention to
planting schedules. We may, however, wish to write a computer program to
do these calculations so as to maintain more complete records and so we
can more easily trace any problems which may occur.
Crops take a preductable length of time to grow from seed to
harvest. This time, combined with the rate of consumption determines the
rate at which the plant should be planted. Since plants do not have to
be harvested on a fixed date, but rather over a range of dates, plantings
of somewhat larger batches than that for a single meal may be used.
However the overall effect will be a continuous planting schedule, rather
than the usual method of planting all your 'acerage' at once--and then
harvesting all at once.
Food storage in the Biosphere is very limited due to the fact that
food is, in essence, essential elements locked up as the foodstuff.
Those elements are required by the biosphere to continue operation. An
example is carbon dioxide (not quite an element, I realize, but it makes
the point); a single potatoe will require more carbon dioxide in it's
growth than there is in the atmosphere in the biosphere. Should you then
put that potatoe in the 'fridge and save it you have, in essence, removed
all the carbon dioxide from the air. Naturally there are other things
going on to replentish the carbon dioxide, but the amount you have
removed will decrease the efficency of the system and should more
potatoes be added to your storage bin you will quickly run into trouble.
Therefore food storage, beyond a very short period, will be quite
limited.
Current status:
We have begun a gradual build-up of hydroponic food production.
Our method aims to be providing enough food to support one person by the
time the Biosphere shell is finished. Since this is likely several years
away we are progressing slowly; there is no reason to finish the
hydroponics systems and have no place to put them!
This is not to say we are not progressing. We are well on our way
towards our initial goal of producing 25% of the food required for one
person; the hydroponics boxes are built and in place and some of the
watering systems have been built. We have planted 37 plants, 17 of which
have germinated (the potatoes, which are the furthest along, are
'crawling' all over everywhere!) Crop plantings shall proceed on a
regularly in the desire of producing a constant flow of food from the
hydroponics. This crop cycling usually is not practical in an unenclosed
environment due to weather considerations. In a controlled environment
it is not only possible but desireable for it increases the productivity
by allowing plants of a given size to occupy only the space needed for
photosynthesis--in a natural environment moving the plants around so they
occupy a minimum of space is impractical (to say the least!).
Since we are not working with a total system yet ridged cycling of
planting dates is not yet needed. We are planting on a 2-3 week cycle
right now, though not everything being grown is planted at each planting.
As the system works towards completion these planting dates will become
more and more frequent and less and less flexibility can be allowed as
the consumption of these plants provides more of the person's diet. When
the system is complete plant cycling will be fairly fixed, especially in
terms of calorie & nutrient production requirements. Thus, while any
given crop may be substituted the total production must result in a
sufficient number of calories and nutrient for the Biosphere inhabitant.
Conclusion:
Most plants require 75-100 days to mature in an ideal environment.
This requires that each plant to be eatten must be planted that far in
advance of the desired date of consumption. Animal food sources must be
similarly managed. While not completely inflexible this requirement
shall require considerable forethought in order to maintain an adequate
diet.
Larger systems will provide increasing flexibility, but in a system
the size we are constructing crop cycling becomes of prime importance in
the regulation of food supply. Improper planning will result in an
inadequate diet. This is the reason we are begining to plan crop cycling
and management this soon in our efforts; while not needed now it will
become critical as the crops move toward providing one person's food. A
good cycling schedule should be implimented from the beginning to assure
a minimum of 'peaks' and 'valleys' in food production.
ON other matters:
Our contract to lease the land on which the Biosphere is to be built
is moving ahead, and it is expected to be signed well in advance of the
May deadline.
While we have not done too much on aero-space craft design since the
last report on it we are devoting the majority of our next meeting to
mapping out a strategy for design of our test model. While this project
is not currently active, and will not be for some time to come, we feel a
that the complexity of the project requires much advance planning for it
to succeed. Therefore we shall continue to have occasional meetings to
address the problems which will slow or prevent this project so that when
we have the necessary funding to proceed we will have a good idea the
direction we will need to proceed in!
After considerable though I have come to the conclusion we will need
to build the Biosphere shell in such a fashion that we can use it in both
a pressurized mode and a de-pressurized (partially, of course!) mode. I
would hope we could attain +/- 5 psi, though we may have to settle for
slightly less. The reason for this is the conflicting data I have found
which is sufficiently confusing to allow me to question what is the best
pressure. To add to the confusion some kinds of plants may prefer higher
pressures while others may prefer lower. Building the Biosphere shell so
that it can do both will nkwhat complicate the airlock but I feel that
the added experimental flexibility will be well worth it.
While not directly related to ISECCo, my project of re-building my
airplane, a Piper Super Cub, I though I would give a little update on it
since many of our members have expressed interest in the project. (Rides
are a distinct possibility to those who are dedicated members--and can
get here!) Over the winter I have progressed from aiming to do a simple
recover job of the fabric to doing a complete strip job of the plane. I
had been planning on getting it back in the air and then doing the rest
of the job in a year or so, but once I got it all apart in the garage I
figured I probably should do everything and save myself from having to
tear it apart again. (Not to mention I had some unexpected free time
this winter!) I am (finally) at the point where things begin going back
together again; I have stripped the frame of everything, sandblasted it
and it is ready to paint. Then I shall put the new tin I made in, re-
fabric it, put the engine back on, paint it, paint the wings, put the
wings back on and...look, is it a bird? Naw, just Ray out playing eagle
again...(unfortunately to accomplish these tasks shall be rather time-
comsuming--I am into the project around 800 manhours already, and by the
time I'm done it may top 1100!)
Any of you who haven't yet joined and are interested do get in
touch with us. Our minimum membership is only $5 for an entire decade.
Anyone who wants to join can just send Robert, FNRJH@ALASKA, or myself
a note on here (PLEASE include a regular mail address: we have had a
number of responses which we have been unable to answer over BITNET!)
and we'll send you a letter with the information we'll need. Alternatively
you can write ISECCo, P.O. Box 60885, Fairbanks, AK 99706.
--Ray :: President, ISECCo
[end]
Robert J. Hale III
ISECCo Director