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For Steve Stewart re #650
Thanks for this informative and provocative post!
In a closed environment, nothing is lost.
However, the study done by Bryce Myer provides an important datapoint for those who might be planning a closed life support system for humans away from, Earth. It would appear to be necessary to use extra energy to recover needed atoms from where they end up.
Can I offer you the challenge to try to see how that might be done? Obviously it must be done, because there are few destinations like Mars, where an open cycle system might work.
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NASA conducted an experiment at the Johnson Space Center a number of years ago. Called "Advanced Life Support", this experiment sealed one person in a chamber with plants gown. The goal was to produce enough food to feed that person on a vegetarian diet, and balance O2. It included a bed, sink and shower, and an incinerating toilet. They found plants sufficient to feed one person would produce 3 times as much oxygen as that person consumed. And yes, that means one person does not produce enough CO2.
Basic chemical formulas.
Photosynthesis (overall):
6 CO2 + 6 H2O → 6 O2 + C6H12O6
That last large molecule is a simple sugar called a polysaccharide.
Cellular respiration in humans or any animal:
6O2 + C6H12O6 → 6 CO2 + 6 H2O
Notice cellular respiration is exactly the opposite of photosynthesis. Since it's a closed loop then how can plants produce 3 times as much O2 as humans need? The answer is you're not looking at the whole system.
Much of the plants are not edible by humans. There's leaves, stems, roots, etc. If you were to consume all of that, then oxygen/CO2 would be balanced. So how to do that? Biosphere 2 was an experiment in the desert. A small group of people locked themselves into a large glass greenhouse with simulations of several ecological systems. They had a separate farm or garden to grow food. Because it was built in a desert, they tried to cut cost by using local soil which was mostly sand and mix in some imported twigs. As the twigs rot they become organic matter in the soil, feeding crops. However, they forgot to take into account oxygen consumed by the bacteria that rots the twigs. The bacteria consume O2 and produce CO2. There wasn't enough O2 for the humans so they had to intake a large and measured amount of air. They also had a problem with food. They counted on beans supplying most of their protein. But the bean crop failed due to blight. They tried to clean the soil of blight, but every time they thought they succeeded, as soon as the plants were about to produce beans, the blight came back.
My point is if you include composting unused plant material, that will consume O2 and produce CO2. Also any system we discussed is not pure vegetarian. We have often discussed aquaponics. That's hydroponics integrated with aquaculture. A pure hydroponic system requires nutrient solution. A simple means to make that solution is to dissolve fertilizer in water. If your source of fertilizer is Mars dirt, then it's an open system. And industrial processing requii to extract and purify fertility from Mars dirt would require more effort and energy than just treating Mars dirt to become arable soil. Use soil in trays in a greenhouse, let plants extract the nutrients themselves. However, with aquaponics you feed the fish with parts of the plants that humans do not eat. Fish poop is used as fertilizer in hydroponics. I doubt aquaponics can provide all food humans require, but can provide a significant portion. But now factor in O2 consumed and CO2 produced by those fish.
For the Large Ship, I proposed using electrolysis across a semipermeable membrane to extract salt from human urine. On Mars you may want to extract salt from Mars dirt. Before electrolysis, a membrane would extract most but not all water. The remainder would be decomposed by bacteria. Urea is CO(NH2)2, which combines with one molecule of water to form CO2 and 2 molecules of NH3 (ammonia). The ammonia is further broken down by different bacteria to become nitrite, NO2-. Still other bacteria break that down to nitrate, NO3-. Nitrate is nitrogen fertilizer for plants. The process takes months. Uric acid and creatinine are more complex. These are most of what makes human urine but there are other compounds. You must factor CO2 produced by bacteria to breakdown urine.
Then there's human feces. For the ship, processing feces is too complex. Either composing feces or grey water sewage processing can turn feces into fertilizer. Either takes months and uses multiple species of bacteria. Something not practical on a ship, but can be done on Mars. Again, factor in CO2 produced by that bacteria.
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For RobertDyck re #652.... speaking of NASA...
https://www.yahoo.com/news/nasa-awards- … 34415.html
United Press International
NASA awards $2.3 million to study growing food in lunar dust
Mark Moran
Wed, November 22, 2023 at 1:16 AM EST·1 min read
3UPI
An illustration depicts NASA's Viper rover making tracks in the lunar dust as it travels near the moon's South Pole. Image courtesy of NASA
Nov. 22 (UPI) -- NASA has awarded $2.3 million to scientists to study how to grow vegetation in lunar soil as human exploration prepares to go beyond Earth's atmosphere, scientists said Tuesday.Researchers say their priorities are advancing work that will grow organisms in lunar soil as part of the Thrive in DEep Space, or TIDES, program.
"The ultimate goal of the TIDES initiative is to enable long-duration space missions and improve life on Earth through innovative research," NASA said in a statement. "Space Biology supported research will enable the study of the effects of environmental stressors in spaceflight on model organisms, that will both inform future fundamental research, as well as provide valuable information that will better enable human exploration of deep space."
The projects will test how lunar soil, also known as regolith, works as a "growth substrate" for crop-producing plants "including grains, tomatoes and potatoes," NASA said.
Researchers will also work to understand how growth in lunar regolith influences plant and microbial interactions, and how in turn, these interactions affect plant development and health. They will identify and test bioremediation methods and techniques to enhance the ability of regolith to act as a growth substrate, and understand how lunar dust exposure impacts host and microbial interactions "in human-analogous model systems under simulated microgravity conditions," the NASA release continued.
11 grants have been awarded to ten institutions in nine states
The research, which will run from 2024-2027, will focus on the same type of regolith NASA has located at potential landing sites for future moon exploration missions.
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What to plant in a greenhouse: 10 top crops to grow
1. Chilies
Chilies are a fabulous ingredient in the kitchen, adding a kick to curries, stir-fries, pasta dishes, and everything in-between. And if you're short on space and have opted for one of the best mini greenhouses then they're a brilliant addition.
Learning how to grow chilies is relatively simple. They love bright light, shelter, and warmth, which makes them the perfect match for greenhouses. Start off the seeds in a heated propagator if your greenhouse is unheated, or indoors on a sunny windowsill, covered with a clear plastic bag. Once germinated, remove them from the propagator (or take away the bag). Transplant seedlings into individual pots when leaves appear. The RHS advises to keep them at a temperature of 60–64ºF (16–18ºC) and water regularly.
From the ferociously hot Scotch Bonnet 'Animo Red' to the sweet and mild 'Trinidad Perfume', there are all kinds of varieties to try. And don't forget that as well as using them fresh, you can dry them to add to dishes all year-round.
2. Tomatoes
Learning how to grow tomatoes is an easy skill that will reward you with the most delicious summer fruits. As they are tender plants, they do very well in greenhouses, offering a longer growing season than those grown outdoors.
You can choose between bush or cordon varieties. Bush ones don't require staking or pinching out, so are often the best type to start with if you're a beginner. Whichever you choose, providing some sort of shade in the very height of summer can be useful to prevent tough skins.
Put pots of sown seeds on a warm, bright windowsill or in a propagator to encourage them to germinate. When it's time to transplant them into their final positions, gardening expert Monty Don of Gardeners' World advises to plant them deeply – 'at least up to the first leaves.' This will encourage them to grow more roots.
3. Cucumbers
Learning how to grow cucumbers is another top choice for what to plant in a greenhouse. These delicious veggies are perfect for summer salads or sandwiches. Plus, homegrown ones taste so much better than ones bought in the shops.
It is important to note that there are two types of cucumbers: ones suitable for growing in greenhouses and ones that are grown outdoors. Greenhouse varieties provide long, smooth cucumbers. If you opt for an 'all female' type, you won't need to pinch out the male flowers (these are the ones that don't have immature fruits growing behind them).
Cucumbers are another crop that can be trained upwards, saving on space. Don't let them get too cold – the RHS recommends keeping the plants above 53–59°F (12–15°C).
Best time to plant: Mid-February to mid-March if you're growing them in a heated greenhouse and April for unheated greenhouses
4. Aubergines
There are lots of decisions to be made when it comes to choosing a greenhouse. If you opt for a heated one, you can start some crops earlier. In the case of aubergines, this can be as early as January.
Transplant plants to their final position in spring. You'll need to provide stakes for most varieties to support the heavy fruits. Mist the leaves and water regularly, and feed periodically with a high potassium fertilizer when fruits begin to appear.
They're a delicious and versatile ingredient and can be the real star of the show in many vegetarian dishes.
Best time to plant: January if growing in a heated greenhouse, otherwise February onwards.
5. Potatoes
If you learn how to grow potatoes in your greenhouse during the leaner months, you'll give yourself and your family a supply all year long. Plus, the greenhouse will keep them frost-free.
If your greenhouse is a smaller design, you can grow potatoes in bags, containers, or a barrel. You do need to chit them first – this is when you encourage them to sprout before you plant them in your greenhouse. You can do this in January and February, then plant them in your container about six weeks later when the shoots are about an inch high.
Best time to plant: Early spring
6. Brussels sprouts
They may have had a bad rep over the years. But with some simple cooking skills, there are ways to transform the humble sprout into a delicious side dish. Plus, Brussels sprouts are a great source of vitamin C and folate, and the 'Brodie' variety has good holding ability and is disease resistant.
Sow seeds in a greenhouse for a head start. You can then plant them outdoors in early summer. There's more advice on how to grow Brussels sprouts in our guide.
Best time to plant: February
7. Peas
If you sow peas early enough, they will be ready for your plate in early spring. Sow them alongside other hardy plants like leeks and sprouts, so that once the warmer weather appears you can plant them out.
Peas do like a bit of warmth to aid their growth, so investing in a heated propagator could be worth it. This particular variety of pea pictured above can also be used in salads and is highly nutritious and easy to grow. It also provides a second crop a few weeks later.
Best time to plant: February onwards
8. Kale
Full of nutritional value and called a 'superfood', this dwarf variety of kale was introduced before 1865 and produces an abundance of tender and delicate densely curled green leaves, of which the younger ones are perfect for salads.
For salads, you can sow it all year round in your greenhouse. But, if you want it to mature then you should transplant seedlings five weeks after sowing into rich firm soil outdoors, with plenty of well-rotted manure dug in.
Best time to plant: Early spring if aiming to plant out
9. Cabbages
If you start your summer cabbages off in late winter, they'll be ready for planting outdoors in the spring. They are a 'cool season' veg, which means they do well in greenhouses when it's colder.
Rich in vitamin C and antioxidants, some varieties are delicious eaten raw as well as cooked. All you need to do is sow some seeds in a tray with compost, water well, and watch them grow until they are ready for transplanting into larger pots.
As the weather gets warmer, get them accustomed to outdoor temperatures by placing them outside during the day, then plant them out around 18in (45cm) apart in raised garden beds.
Best time to plant: Late February to early March
10. Melons
A slice of juicy, fragrant melon is a real treat on a summer's day. These crops thrive in heat and humidity. So, if you have a greenhouse, it's not too tricky to grow your own.
They need fertile and moisture-retentive soil. If space is at a premium, consider growing your melons vertically. Keep watering regularly, until the fruit begins to ripen, then reduce. Similar to growing tomatoes, provide shading if it's very sunny.
It's also important to provide ventilation when the plants are in flower – this will allow the crops to be pollinated, as the RHS explains.
Cantaloupe are firm favorites with their sweet, orange flesh. Alternatively, how about learning how to grow watermelon with our guide?
Best time to plant: Early to mid-spring
Its not just about what to grow as how much to plant and when so as to get the best of the food for the diet that we willl have to deal with.
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I ran into this yesterday: Plant(Azolla): https://www.msn.com/en-us/health/nutrit … r-BB1iwSjO
Quote:
Common plant could help reduce food insecurity, researchers find
Story by Jeff Mulhollem • 2d
https://www.bing.com/videos/riverview/r … &FORM=VIRE
Quote:
Azolla (Azolla caroliniana) - A Water Plant You Need to Know About!
The plant is a bit like duckweed in its life cycle, but can fix Nitrogen which could be important on Mars.
It also does not need soil, which could be an advantage.
Done
Last edited by Void (2024-02-21 11:15:52)
Done.
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40 years of crop research shows inequities
Asystematic analysis of 40 years of studies on public crop breeding programs found that cereal grains receive significantly more research attention than other crops important for food security, such as fruits and vegetables; only 33% of studies sought input from both men and women household members; and there is significantly less research in South America, the Middle East and North Africa than in sub-Saharan Africa.
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