From: Terry Kok To: Dean Calahan, FoB Subject: digest 10 Date: Wednesday, May 10, 2000 4:15 PM

Date: Thu, 13 Apr 2000 19:26:28 +1000 From: Conolly Subject: [Civ-Culture] (AGR) Aust native bees

[ To Mars Society Civilization & Culture Group ] [ from Conolly ]

For anyone interested in the possibility of using Australian native (stingless) bees for crop pollination in a greenhouse, the Native Bee Research Centre and Dr Anne Dollin have kindly sent me some informational booklets and I've done a bit of reading.

Here is a quick summary of these bees and a few of the major pluses and minuses of the social species of Australian native bees. SPECIES TYPES There are about 10 species of social bees in Australia, of these, three are common: Austroplebeia australis is found in the sub-tropical regions of northern NSW and Queensland. Trigona hockingsi is common in the tropics of NE Queensland and the Northern Territory. The third species, _Trigona_ _carbonaria_ may be the most likely candidate for greenhouse pollination, since it is found as far south as southern coastal NSW, so tolerates cooler temperatures in the range of 18-30 degrees C.

POLLINATION OF CROPS Research on the commercial/agricultural potential of T. carbonaria is unfortuantely still in the early stages. Most of the investigations have focussed on the pollination of native Australian plants, but a few species are known to be pollinated by T. carbonaria and they include tropical plants such as mango, macadamia, coconut and pawpaw (papaya), as well as a broad range of herbs. So far, research has focussed only on plants that the bees would be likely to encounter in their natural environment, but it's worth noting that this species doesn't appear to be too fussy in it's foraging - mango, pawpaw, choko (chayote) and coconut are not endemic to Australia and are definitely pollinated by native bees. Several appendicies to _Crop Pollination With Australian Stingless Bees_ show that native bees will visit a wide range of crop plants (onion, strawberry, peach, plum, sunflower, cucumber, watermelon, coffee etc), but, because these studies were performed in the wild, native bees were also competing with imported honeybees, so it is difficult to prove that native bees were the pollinators.

There are a few plants that T. carbonaria, which is only 8mm long, cannot pollinate, simply because it lacks the strengh the "buzz pollinate" [grasping the plant and vibrating it to shake loose pollen], or because it's simply too small to reach into the plant. Among these are tomato, passionfruit, lucerne, bananas and brazil nut. Investigations show that stingless bees prefer to visit plants with white or yellow flowers (might be good for beans?), and flowers that appear in bunches.

SPECIAL GREENHOUSE REQUIREMENTS Native bees, which prefer subtropical weather, won't forage if the temperature is too low. So a greenhouse would need to be heated to at least 18 degrees C. The bees are more active as the temperature rises, up to about 26-28 degrees. Depending on what the ambient temperature of the greenhouse is intended to be, native bees may thrive in conditions where honeybees would die. They also perform a spiraling flight to orient themselves as they leave the hive and Dr Dollin has found that this means a 2m high ceiling is too low, so the greenhouse may need to be 3 or more metres in height. To prevent the bees, which are quite small, from drowning, the greenhouse walls must not drip with condensation, though this profligate use of water isn't likely to be as big a problem in martian conditions.

HONEY PRODUCTION: Although these species do produce honey, it is not as abundant as from honeybee hives. Generally they only produce about 1.5kg/year, much of which is needed by the bees themselves. So, native bee honey would tend to be a rare treat (no mead, sorry)! On the up side, I understand it's much more fragrant and flavourful than regular honey.

OVERALL Pluses: Doesn't sting. Not a fussy forager. Resistant to honeybee diseases. Prefers to forage close to home (<100m). Thrives in a tropical climate (as in a greenhouse). Forages well in a greenhouse (honeybees don't). Native bee species do not swarm away, since the queens don't fly.

Minuses: Beekeeping with native species is in its infancy - little hard research. More trials are needed to prove that stingless bees will pollinate the food crops we have in mind. Currently, it's difficult to acquire hives of native bees (though they seem to reproduce well). So, we'd need to do some research with other food crops, particularly with legumes and salad-type plants, but it does sound promising. Keeping Martians fed through the wonders of modern entomology, Bev Conolly Janis Jaunbergs - 11:10am Jan 1, 1999 (5.1) University of Cincinnati pollination Cereals are pollinated by wind. Potatoes don't need any pollination. I don't know about beans. The only plants that I know for sure are pollinated by bees, are certain fruit trees.

John Creighton - 11:30am Jan 1, 1999 (5.1.1) pollination Are you saying a paint brush doesn't work?

John Creighton - 09:26pm Jan 1, 1999 (5.1.2.1) Pollination Hey, I was just testing what he said and by the way I am not sure my question was answered anyway. To show further my ignorance in agriculture, I would like to inquire what percentage of greenhouses use bee's as a method of pollination. And obviously, as the size of the crops grow you are going to want more efficient means of pollination. And of course I can obviously see other advantages of bee's like another food source for us or another part of our (crops/(eco chain)?) (I think I heard something like cows can easily brake down alcohol for an energy source and they don't get drunk). Well if we are going to use bee's early, we may want to check the crew for allergies. [Oh thought I'd throw in paintbrush pollination allows selective breading.]

Janis Jaunbergs - 01:33pm Jan 2, 1999 (5.1.2.1.1.1.1) University of Cincinnati plant nutrients & pH Potassium and phosphorus are present in Martian dust and rocks. Nitrogen fertilizer can be either produced from hydrogen and Martian atmospheric nitrogen, or appropriate crops can be grown that utilize nitrogen gas (certain legumes). For pH to shift considerably away from neutral there must be some reason. On Earth, it is acid rain or too much limestone in the soil, that shifts pH to acidic or basic, respectively. Silicate rocks by themselves are neutral. If Martians find some salt deposits, they can produce both sodium hydroxide and hydrochloric acid (and chlorine for making PVC). With easily available hydroxide and acid you can adjust whatever pH you wish. Once you start growing crops, there will be enough disposable biomass to make organic soil with good pH buffering properties. If you don't see how terrestrial methods can be used on Mars, that doesn't mean there are no solutions at all.

Janis Jaunbergs - 03:19pm Jan 2, 1999 (5.1.2.1.1.1.1.1.1) University of Cincinnati earth worms yes, they are good for food, some native peoples eat them. By heavy processing lots of various cheap meat substitutes could be produced from earthworms. Imitated hamburgers or imitated shrimp, choose whichever you like, if you can forget about their origin. Or feed fish with them. Allen Bryan - 10:00pm Jan 3, 1999 (5.1.2.1.1.1.1.1.1.1) Furthermore.... earthworms provide vital soil turnover/replenishment: very good for long-term farming initiatives.

Joseph Lee Barlow - 06:58pm Jan 4, 1999 (5.1.2.1.1)

My apologies for getting off subject Ansewer to question of bees in greenhouses.Bees are not needed in greenhouse operations here because ornamentals are crops grown.Food crops are grown in open fields.Some crops require pollination to reproduce,but you get the harvest first.Some crops require pollination to produce the harvest.Black loam top soil is needed to produce crops without fertilize.Options are to plant things that will grow in poor soils then plow them back in allowing earth worms to incorperate the vegitable matter into the soil.It will take many crops to build soil up enough.Only edible crop that I am aware of that will grow in poor soil is prickly pear cactus.The other option is to provide chemical fertilizer this is true for aquaculture also.The chemicals needed will have to be processed from air or mined from planet.What is current ph of martian soil,it did rain there once. Fish farming is more difficult,water would require airiation or fish would die.Some soils will not hold water, may have to line pond.Fish also require a certain ph balance.Algee and planton produce oxygen and some fish feed on those plants,not necessarily the ones you would like to eat,but prefferable to worms.

Joseph Lee Barlow - 07:24pm Jan 6, 1999 (5.) Algee farm Pond raised red algee is edible.Chinese have grown it for ages.Question is are there enough nutrient in soil to be used by algee.Algee pond doesn't have to be pressurized,just covered to prevent evaporation and provide enough heat to keep it liquid.

Christian Marriott - 06:00am Jan 7, 1999 (6.) Atmospheric composition I was wondering what Atmospheric pressure and composition would be most appropriate for a Martian greenhouse ? Option 1: 3.8 psi is the absolute minimum that a human could tolerate so one possibility would be a 3.8 psi 100% CO2 atmosphere, this would allow the 'farmers' to work with an oxygen mask only. Option 2: another possibility would be 4.75 psi O2 + 0.25 psi CO2, this would allow the 'farmers' to work without pressure suit and oxygen mask but I am not sure if the CO2 level is high enough for plants to grow. If the CO2 needed to be increased then the O2 will also have to be increased proportionally. As we need to use as little greenhouse material as possible then option 1 appears to be preferable.

Janis Jaunbergs - 08:34am Jan 7, 1999 (6.1) University of Cincinnati Greenhouse atmosphere. We have got only 0.04% CO2 in Earth's atmosphere. Plants grow best at about 1% CO2 on Earth, that would translate to about 0.13 psi of CO2. Plants need some oxygen, too. Significantly more CO2 than .13psi would be harmful to both plants and humans. Therefore, something like 4psi oxygen atmosphere with 3% CO2 might be optimal. Also, it is probably not wise to put humans under marginably breatheable atmosphere - human performance will suffer. Maybe it makes sense to initially use oxygen masks in the greenhouse, and inject about 0.1psi CO2, 1 psi oxygen, plus 3 psi total of nitrogen and argon, the inert gases of Martian atmosphere. Then plants would produce the rest of oxygen, that could be later supplied to the living quarters.

Joseph Lee Barlow - 05:50pm Feb 10, 1999 (6.1.1) Inert gases WAVAR gets water from atmosphere,the return vehicle will gather carbon dioxide from atmosphere to make methane.What type machine will be used to collect nitrogen from atmosphere and how long will it take to collect usefull amount.

Joseph Lee Barlow - 06:25pm Jan 7, 1999 (6.2) Algee farm Why not use robotic harvester.Pressure can be kept low.Only enough pressure to keep water in pond and stimulate algee growth.Algee is simple crop,if tire of algee, edible snails or carp could be introduced which would feed on algee.

Janis Jaunbergs - 09:01am Jan 8, 1999 (6.2.1) University of Cincinnati snails and fish What is the tolerance of various potential food animals for low pressure? Animals are better than robotic harvesters, they would eat algae or whatever plants are grown, and multiply for human consumption. Robotic harvesters are less reliable and have to be manufactured. Anybody has an idea, what oxygen pressure (above the water) is necessary for carp?

Joseph Lee Barlow - 06:03pm Jan 8, 1999 (6.2.1.1)

Oxygen one problem Oxygen above water important,but you may not understand why.Fish consume oxygen out of the water they swim in.On earth natural forces,rain and wind,replenish the water with oxygen.On Mars machines will have to do it,just like they do here during summer droughts.Fish die without oxygenated water.Second problem fish like carp eat vegitable matter.This is good except for the fact that to stimulate plant growth you have to fertilize pond.AS I have tried to explain to you for any type food production to take place on mars you will need many thousands of tons of fertilize mined from planet before you attempt to build first greenhouse.If you use plants that will grow in poor soil to build up organic matter in soil,it will take many years to build up soil enough to plant food crops.Don't take my word for it.There must be someone out there with a degree in agriculture, since the only ones you listen to are other scientist.My only experience is real world gardening to help feed my family.A step by step plan needs to be established with priorities in proper order,to make food production on mars a reality.

Janis Jaunbergs - 03:29pm Jan 9, 1999 (6.2.1.1.1) University of Cincinnati fertilizer It doesn't take thousand tons of fertilizer to feed a base (how much do you use to feed your family?) I have some experience with agriculture, too. You only need as much fertilizer as you are removing with food from the system (exporting it to other bases, for example) Everything else goes in a closed cycle - nitrogen, phosphorus and potassium cannot disappear just like that. For the startup you need only as much fertilizer as the total biomass is going to contain. If we have got ten tons of plant biomass for each Martian, that would be few hundred kilograms of fertilizer. That amount could probably be extracted from Martian soil by plants, without a need for large scale mining. The exception is nitrogen: plants (more exactly, certain bacteria living on plant roots) can absorb nitrogen gas directly, or else we need a portable ammonia production unit, from hydrogen and Martian atmospheric nitrogen. About tundra: it is not very productive ecosystem. The low temperature advantage would be outweighted by the need for much larger area. Ponds are probably close to the best, both because of high productivity and good heat capacity (to buffer day/night temperatures). And, about fish: Of course, they use oxygen that is dissolved in water. That oxygen is produced by algae (in amount, equivalent to their food value.) Oxygen pressure above water merely indicates the oxygenation level of water, and there would be net flow of oxygen out of water, since edible biomass is removed from the pond. You don't need to oxygenate the pond artificially.

Joseph Lee Barlow - 08:44am Jan 24, 1999 (6.2.1.1.1.1) Reply to Janis I use 500 lbs. of 13-13-13 per year.Still spend lot on groceries because family refuses to eat same thing day after day.On mars vegitarian diet likely.Crop choice essential to nutritionaly balanced diet.Crop choice limited by fertility of soil and temperature of soil.

Janis Jaunbergs - 09:01am Jan 24, 1999 (6.2.1.1.1.1.1) University of Cincinnati fertilizer Don't forget that most of the fertilizer applied in terrestrial agriculture get washed away in groundwater. Martian greenhouse would be a closed system in this sense, the only loss would be what is incorporated into those plant products that are exported from the base. You can recycle a very limited amount of phosphorus, nitrogen and potassium, and still have them in the system at pretty high concentrations.

Joseph Lee Barlow - 10:45am Jan 30, 1999 (6.2.1.1.1.1.1.1)

Fertilizer needs Check this out-http://www.hgtv.com/gby/gby-106.html If you remember U.S. history ,reasons for westward migration,as top soil was depleted farmers moved west in search of better soil.Mars has soil far less fertile than the depleted soil of east coast.Like it or not fertilize will be needed on mars for greenhouse operations to succeed or organic material will have to added to soil until it reaches farmable fertility.

Joseph Lee Barlow - 10:11am Jan 9, 1999 (6.2.1.3) Aquadic farm Hay bale placed in shallow pond decays and provides food for crayfish.Austrailian variety is very large would make excellant food source.Would hay decay in water or would bacterior and nematodes have to be added to pond too aid in decomposition of hay.Grasses for hay cultivation require fertilize.Hay baleing requires machines.

Joseph Lee Barlow - 06:40pm Jan 12, 1999 (7.) Crayfish may not be good choice Creyfish have formidable pinchers and they like to tunnel.If plastic greenhouse is to be used they could cut through bottom.If size of greenhouse is to be limited to 1 acre it may be better to use apple snails and earth worms as source of meat protien.They both feed on vegitation but do not compete.worms perfer matter incorporated into soil,snails eat green growing aquatic vegitation.Worms could be raised in beds and fed organic vegitation.This would make harvest easier.If we use ancient channel and row farm technique Apple snails could be raised in channels.Have to pick row crops that apple snails don't eat.With limited space these two spiecies with their high population density and reproductive rate may be best source of food.Grass carp would require lots of space ,have low density per acre,if anyone noticed from web address I referred to in earlier post.

Joseph Lee Barlow - 07:34pm Jan 13, 1999 (8.) Salt would aid survival Cabbage would be good crop,when planted from seed takes 120 days to produce harvest without pollination.Late Dutch variety produce heads size of basket balls.If kept cool will keep for months.However if salt is available and clay churns it can be shredded and made into sour crout.Crout will keep for years.Radish and turnips could provide quick harvest.Brocclie will produce 1 large head,but if fertilized and watered it will produce dozens of smaller heads makeing it very desireable for mars project.Seeds are very small 1lbs. of each properly planted would plant acres.Diet may be limited at first but job of first colony is to survive long enough to open new frontier.

Robert Parker - 09:27pm Jan 26, 1999 (8.1) Cabbage and other leafy greens also provide oxygen Cabbage and other leafy greens are also the best candidates for a bio-regenerative life support system due to their surface area for respiration.

Joseph Lee Barlow - 11:12am Jan 23, 1999 (9.) Potential proplem In reviewing pathfinder results it stated that dust settles out of atmosphere at rate of .33% a day.At that rate how long would it take for dust accumulation to block sunlight entering greenhouse.How can greenhouse design be improved to prevent dust accumulation on plastic roof.

Anthony Santana - 01:33pm May 31, 1999 (9.1) Dust Storms This is not the only problem. Though one solution to the dust problem is John's idea of blowing out long canals or underground rows for the greenhouses. Then one could simply walk along the top of these rows with a large enough broom, or these type of brooms could be mounted on booms on a rover driving along between the canals, and sweep off the dust from the top of the plastic ceilings. The more I look at it, the more sense it makes to put the greenhouses within the regolith, the ground also shields the plants from all radiation that does not come in directly overhead, but providing two 'sides' to the greenhouse, also saving on material. But let me highlight the big problem. DUST STORMS! I have read that sometimes dust storms can last MONTHS on the surface. Fine, they may not have much pressure behind them (or they just might somehow), but they would do a grand job of blocking off solar power collectors, killing off plants that depend on sunlight, and leading to depression among the colonists as months without sunlight progressed. I think we have to devise emergency contingency plans for these storms, such as solar reserve collecting pools that utilize some natural liquid or solid from mars to 'store' solar energy, or ceiling materials that can act as overhead 'mirrors' to reflect light energy that we release from storage over the entire ceiling down, mimicking sunshine. Or at worst an emergency relocation plan for the humans to another outpost.

Joseph Lee Barlow - 03:03pm Jan 24, 1999 (10.) Balanced vegetarian diet Bananas are very nutrisious,tropical plant requires high temp and lots of water.Solar furnace can heat water to 3,630 degrees with aid of radiant heat system should be able to maintain tropical temps even through cold nights.Comptons on line encyclopedia source of info.

Janis Jaunbergs - 05:02pm Jan 24, 1999 (10.1) University of Cincinnati nutritious? I'm not so sure, at least about the common, sweet variety. For me they are not nutritious at all. Eating bananas is like eating starch. People need protein, and not too much of sweet fruit. Try living couple days on banana diet yourself.

Joseph Lee Barlow - 05:29pm Jan 24, 1999 (10.1.1)

Nutrition-Comptons encyclopedia "The banana is a staple food of many tropical peoples. The ripe fruit contains many of the necessary elements that are essential for a balanced diet. Although it is 75% water, the banana contains fat, natural sugars, protein, potassium, and vitamins A, B complex,and C." I would suggest several acre size greenhouses each adjusted to conditions of crop within. Most people tire of limited diet.

Janis Jaunbergs - 09:07am Jan 25, 1999 (10.1.1.1)

University of Cincinnati bananas OK, those are not the sweet bananas that tropical people usually consume. Don't forget, however, that malnutrition is widespread in tropics, not so much in the total energy intake, but specifically the insufficient protein. Bananas contain some protein, but people need balanced protein, not any protein. You've to grow beans, potatoes, cereals, and bananas would possibly be just one of many different crops.

Joseph Lee Barlow - 06:06pm Jan 28, 1999 (10.1.1.1.1) Protein and pollination John's paint brush could pollinate bananas,beans are another story. Beans require bees for pollination,blooms are small,easily knocked off and number in thousands.Bees and therefore crops which require pollination to produce harvest would not be wise at fist.Earth worms better source of protein provided limited space.

Joseph Lee Barlow - 06:21pm Jan 28, 1999 (10.1.1.1.2) Promise of mars agriculture Fruit trees could be tricked into producing two crops per year and would reach bearing age twice as fast as they do here.If efficient means of raising and lowering internal greenhouse temperature can be achieved,trees can be placed into dormancy then fooled into blooming early giving more fruit per year.Healthier fruit with no insects,fungus or diseases to destroy crops.

Anthony Santana - 01:35pm May 31, 1999 (10.1.1.1.3) Bananas I like bananas! ::Now there's an intelligent commentary for you::

Mark Peiffer - 09:56pm Feb 6, 1999 (11.) Plant studies in Greenhouse production I find the discussion presented here to be very exciting. I own a Greenhouse and have talked about developing a kind of small Biosphere project for area schools. I thought I would share some research that I acquired from NASA and the Biosphere follow on projects. food production in a standard Greenhouse is measured by mass per area and time. For our discussion I would propose that we import minerals and vitamins. The Greenhouse would produce Calories and the crops would be described as calories / meter **2/day. Crops considered on earth for temperate climate where time is a concern are: lettuce, radishes, turnips, onion, cabbage, kale, collards, beets, chard Crops investigated that mature slower are wheat potatoes and Strawberries. In warmer conditions soybean, sweet potato, peanuts, and rice can be grown. Given optimum conditions crops grown for nutrition density were studied by NASA. Wheat Soybean Lettuce Potato 11.3 4.2 7.1 16.7 grams/m*m/day edible material This would start the wheat versus potato debate. Picking a potato might be harder and the edible material is the root of the plant. On a final word insects might be a form of food that could be utilized. Much of the unusable plant material could be ingested by a cycle of mold and ant or termite. Their eggs could be processed to provide a vital supplement. I have been told that termite eggs are pretty good in Africa. I haven't actually tried them but at least there would be no legs to deal with.

Janis Jaunbergs - 07:33am Feb 7, 1999 (11.1) University of Cincinnati calories/protein Calories/(square meters x days) is not the best indicator of the usefulness of particular plants. Growing good protein is much harder, that may be the bottleneck. Grams of digestable, balanced protein from (area x days) is the criterion. Lettuce and radish is near useless but for vitamins, which may be cheaper to import from Earth for the beginning. Potato and beans are richer in protein. Potato protein is very balanced. Also, its important to rotate the crops, so the right rotation sequence comes into consideration besides the direct usefulness of specific plants. Rotation decreases fertilizer requirements and helps to control plant pathogens (fungi, viruses, bacteria).

Joseph Lee Barlow - 07:52am Feb 7, 1999 (11.1.1) Promise of mars There will be no fungi,viruses or bacteria that we dont import.It will be farmers paradise with no pestelence to destroy crops.Seed selection will be critical to preventing importation of disease.

Anthony Santana - 01:44pm May 31, 1999 (11.2) BUGS I think insects and worms are definitely the way to go. I am not trying to be facetious here; the truth is that these creatures provide many desirable qualities: First and foremost, many types of worms are great sources of protein, once they've acquired the proteins from decaying plants or the soil. Perhaps species exist that pull the protein right from regolith, for example, that eat raw potassium salts, and so forth. Perhaps from the desert southwest, or that live in the Canadian/Russian tundra. Secondly, insects have very short lifespans, living in the summer months and quickly dying off and breeding so as to return after a long winter. This type of creature is ideally suited to a world with a brief warm temperature period, requiring a life form that will regenerate after a long wintery period. Thirdly, they breed and multiply in large numbers on their own. Assuming the proper critters are found that can eat regolith or blends of dead plant parts and regolith, they could be a great source of biomass, or possibly nutrition. Fourth, their breeding prowess could make them the source of a lot of soil production. What are needed are natural, self-reproducing little machines that can convert regolith to dead biomass, e.g. soil. The right insects and worms could be located to fit the bill, even if they have to live in protected 'greenhouse' environments short term. Note: NO TICKS! lol. Lastly, I am not promoting the idea of eating 'Gagh' or live worms as Klingons do in Star Trek. Dead worms could be easily processed into the type of 'paste' or 'goulash' type meals astronauts eat, and could be canned for long trips as emergency rations.

Joseph Lee Barlow - 07:41am Feb 7, 1999 (12.) Welcome to discussion I am glad to see someone with more agricultural expertize than myself in this discussion.You suggested importation of vitamins and minerals I take it you mean for human consumption.Plants have nutritional requirements as well,the soil of mars is organicly dead.Volcanic soils may have more of nutrients required.Do you know amounts of fertilizer elements required to produce various crops.Nutritional requirements vary from crop to crop.It has been argued here that no fertilizer will be needed to grow vegitables.That the organicly dead mars soil will provide all nutrients and once exhausted the depleted soil would be removed from greenhouse and new soil brought in.Your comments on this would be welcome.As for importation of insects I would urge extreme caution.Termites and ants can be extremely destructive to agriculture whereas earth worms are benificial and good source of protien.Are you familiar with mist type hydroponics where roots are exposed to air and kept moist by nutrient rich mist.Suppose to produce rapid vegitable growth.

Mark Peiffer - 09:44pm Feb 7, 1999 (13.) Replies concerning greenhouse production In response, my understanding of the NASA studies were that corrections were made to reflect the protien content of the study crops. The possible crops would have to be evaluated as to a short term or long term support for nutrition needs. The NASA studies were a short term crop in space. To achieve the complete protien needs a crew would rely on supplements. Or a Mars crew might try an animal crop such as worms -- if determined. The real hope would be to reduce the food component of the payload. To that end calories must be expensive in mass. NASA has focused on a strain of dwarf wheat. Even though a potato crop would produce a larger edible mass. The reasons for this could be that the mass component of edible material would be favorable for wheat. On the surface of Mars this concern would not exist. Another concern may be that harvesting potatos would be more destructive. Again I would think that in the more relaxed space constraints of a Mars greenhouse - potato's would be a better crop. But if the goup would like - I could ask th

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