From: Taber@bio2.com
Subject: Biosphere 2 Agriculture
X-Added: Forwarded by Space Digest
Organization: [via International Space University]
Original-Sender: isu@VACATION.VENARI.CS.CMU.EDU
Distribution: sci
Date: Sun, 3 Jan 1993 23:22:17 GMT

 
 
 
 
My name is Jane Poynter, the Biospherian in charge
of the Field Agricutlure Systems inside Biosphere
2.  Taber MacCallum has given progress reports on
Biosphere 2 and given general outlines.  I thought
I would give a brief outline of the Agriculture
Biome of Biosphere 2.  What I write here are my
own opinions and not to be taken as opinions held
by Space Biospheres Ventures.
 
The Biosphere 2 Agriculture covers an area of
approximately 0.5 acres, which includes the field
agriculture, orchard and domestic animal barns.
It was designed to produce enough food for the 8
biospherians and domestic animals (goats and
chickens), to be non polluting and totally
recycling.
 
Our main staples are beans (mostly a tropical
variety called hyacinth bean, or lab lab), rice,
wheat, sorghum, sweet potatoes, taro, bananas
(green as a starch and ripe as a fruit), papayas
(also green as a vegetable and ripe as a fruit),
peanuts (which give us a large percentage of our
daily fat intake), and of course all sorts of
vegetables such as carrots, squash, eggplant,
tomatoes, chilis, bell peppers, beets and lots of
greens.
 
>From the animals we get mainly milk and eggs.
Meat is quite a luxury, eaten once a week and for
feasts.  We currently have 4 African Pigmy does,
one buck and 2 kids, 10 hens, 2 cocks and 3
pullets.  There are also tilapia fish in the rice
paddies which live off the azolla (a small water
fern which grows on the surface of the water) and
the small crustacea and insect larvae in the water
and mud.  At the outset of the experiment we had
included a breeding pair of Ossabaw Ferrel Swine,
which are a medium sized pig, somewhat larger than
the Vietnamese Potbellied Pig, but much smaller
than a farm pig.  The boar weighed 110 lbs.
However, it became increasingly clear that this
pig, and probably any pig, is not suitable for
this agriculture system at its current level of
production.  There was no starch available for the
pigs, as had been thought there would be when the
decision was made to include the pigs.  I am sure
that this agriculture system will go through many
phases of evolution as we discover what works and
what does not, and how to improve on existing
systems.
 
We use no polluting pesticides to control pest
outbreaks.  We use soap and other such sprays
where necessary, and use many of the commonly used
methods of integrated pest programmes.  We also do
not use chemical fertilisers, but recycle waste
products.  Animal wastes and crop residues not fed
to the domestic animals are composted, human
waste, the wash down from animal barns and the
waste water from the human habitat is cycled
through a marsh waste recycling system.  Our
nutrient recycling in the agriculture is therefore
essentially a closed loop.  There are some
nutrients that may be tied up in forms
unretrievable by plants in the long run, and this
is a possible problem that we may have to face in
the future.
 
As in all new ventures there have been problems
which we are currently attempting to solve, and
doubtless there will be many more challenges along
the way to reaching the afore mentioned goals.
Some of our main problems have been in pest
management which has led to problems with crop
diversity.  Light levels are also of concern as
the plants receive approximately 45% ambient
light. This is because of the shading of the
structure and glass.  The pest problems have
arisen because, despite efforts to introduce a
wide variety of predators and parasites on several
occasions, before closure and once during closure,
the food web is by no means complex enough to
handle the fluxes in pest populations.  We have
also seen the development of damaging population
levels of broad mites which we did not see before
closure at all. This tiny mite has devastated
white potatoes, and is now attacking our sweet
potatoes, despite efforts to control it by
spraying vegetable oil (which we have found to be
the most effective non-toxic spray to date) and to
lower levels of relative humidity as far as
possible as this seems to be the most effective
method of population control.
 
Because of this and other pest and disease
problems our species diversity has been diminished
in the agriculture which of course does not help
in itself.  We begin to rely on fewer and fewer
crops for our main staples, which is not a healthy
situation to be in, especially when one's lively
hood relies upon the crops' success.  Species
diversity is an important factor to consider in
any agriculure system as it is necessary to have
several crops that perform the same funtion in the
diet (such as white potato and sweet potato).
Unpredictable growing conditions may arise and one
crop may do well where the other may fail.
Diversity is also important to maintain an
interesting diet, one aspect of keeping high
morale among the crew of any long expedition.
Both the pest problems and the species diversity
are problems that we are currently trying to
solve, but will also be a large part of the work
being done during the transition phase betwen this
2 year experiment and the next one year
experiment.
 
Then there is the problem of light: the plants
will indeed grow and produce under the existing
light levels, but it makes the plants somewhat
etiolated and much more susceptible to disease and
prone to pest infestations.
 
People have often asked what the Biosphere 2
Agriculture system has to do with space
exploration, habitation.  There are several
answers to that question, but the general answer
is in long term colinization of planets, and
eventually even the totally man made space
colonies as in Gerard O'Neill's vision of the High
Frontier.  There are indeed many methods of
growing plants.  NASA is doing great work in the
realms of hydroponics for maximum efficiency and
reliability in the production of food and have
succeeded in obtaining extraordinary yields,
making the production of food a viable option
during spaceflight.  However, this kind of system
is as yet non-recylable.  The nutrient solution
itself can be recycled, but no way has been found
to date to recycle the nutrients that have been
taken up by the plants themselves.   Hydroponics
will most probably be the way to go for space
flights needing to get materials up out of a deep
gravity well, like that of Planet Earth's, but in
situations where there are materials at hand with
which to make the main bulk of the growing medium,
like on Mars, or possibly larger asteroids, then
the soil based totally recycling, non-toxic, intensive
agriculture approach may well be more viable in
the long run. I will say, however, that I think
domestic animals will be a long time in arriving
in space and are not an essential part of our
system, either for nutrient recycling, or for food
production.  They are currently essential for a
good portion of the fat in our diet, but this can
be remedied by the inclusion of other oil crops.
 
Another aspect of the food production systems
used in space, is the diversity that can
be produced for the human diet.
Living inside Biosphere 2 for 15 months has
shown that food, and the cuisine aspects of the
daily meals, is an extremely important aspect of
group morale.  If someone cooks a poor meal, or if
there is a period of time when the number of
species which end up on our plates is low, or very
monotonous for a period of time, people become
grumpy and somewhat dispondent.  However, feasts
have become very important, where we all make
great efforts to produce favorite dishes like
cheesecake and sweet potato pies, stuffed
chickens, ice creams, rice and peanuts, chutneys
and crepes.  Whilst humans can, for the most part,
tolerate poor living conditions for periods of
time, they do nothing to contribute to group
morale, and high morale on any long space
expedition will be extremely important to ensure
success.
 
In any food production system in space there must
be room for unpredictablility and failure.  Plants
will be plants.  They will grow very differently
with only very small changes in evironmental
parameters, and problems will arise that were not
seen before, or planned for, as we have seen with
the Bisophere 2 agriculture system.  Although many
crop and variety production trials were run under
conditions as close to those in Biosphere 2 as
possible many plants have acted quite differently
under actual Biopshere 2 conditions.  Bananas have
become an extremely high producer for us in here,
which we did not experience in our test beds.
 
Pests are of great importance to consider.  Even
in NASA's environmentally controlled chambers
where they take great precautions against the
inclusion of pests they have seen problems with
pests.  Learning how to exclude pests completely
from a system is very important but there needs to
be a back up system of pest management if
unexpected pest populations do arise.  This
non-toxic integrated pest management approach,
with complex food webs, is an important aspect of
the resarch being done in Biosphere 2.
 
Energy is a big concern in space, both the
acquisition of the energy for artifial lighting
etc. but also the dealing with the heat load
created by electric motors, lights etc.  Using the
sun's photons as far as possible seems the obvious
way to go, but some artificial lighting may be
needed for periods of time or for general
supplementation.  Finding the optimum light levels
for food production, which may not necessarily be
the ideal levels for maximum production/unit area,
is another important area of research which needs
to be carried out.
 
There are many questions to be answered about food
production systems and many yet to be asked that
have not been thought of, but you might say that
the Biosphere 2 Agriculture system is a
step towards the total system's approach to space
agriculture.  This approach and the as yet
non-recyclable systems of hydro and airoponics
have very different applications, just as the
different rocket propulsion systems have their
pros, cons and very different applications.
 
I would welcome food production as a new
thread on the net.
 
Jane Poynter
Biospherian in charge of
Field Agriculture Systems in Biosphere 2