A recent preprint posted to bioRxiv investigates how chickpeas have been successfully grown in lunar regolith simulants (LRS), marking the first time such a guideline has been established not only for chickpeas, but also for growing food for long-term human space missions.
The study notes, "We report the first instance of growing chickpea (Cicer arietinum) in lunar regolith simulants. We used soil regeneration techniques common on Earth with LRS for the first time, using both AMF and VC. We also achieved the first documented chickpea yield in an LRS mixture. Our results show that regeneration methods used on Earth soils can help condition lunar regoliths. Despite promising results, all plants in LRS showed signs of chlorophyll deficiency."
It is on the Moon, it knows it can die due to decompression at any moment and we completely screw up it's circadian cycle with 30+ days. Of course it will be anxious, no need to prove it.
I do not understand the point of these experiments. They're nitrogen fixing with Arbuscular Mycorrhizal Fungi. Why not just do it hydroponically? It's not like you're going to try to fix atmospheric nitrogen on the moon to create soil.
Hydroponics requires biologically available nitrogen too and it has to come from somewhere. The point of these experiments is to explore a wide variety of scenarios. Hydroponics as a growing method has some drawbacks too. Any robust food production scheme in space will likely include a mix of hydro- and geo-ponics (fancy name for soil growing).
Also consider the non-food benefits of living plants and soil. Any long term habitat on the moon or Mars will need living plants for the psychological and air quality benefits. There is a massive body of research that shows the benefits of having trees around. There is even research that shows just smelling healthy soil can be antidepressant.
Let’s say we enclose a large lava tube, one seriously considered approach for long term habitats. Having some greenery would go a long way to staving off Space Madness.
Makes sense that if you can plant plants in a plantable media, over time you may develop that media into something akin to soil, which means you have a more stable grounding for future generations of plants.
(I honestly tried for some alliteration or punnage, this was the best I could do, forgive me 😄).
I am not familiar with what is required for hydropony, but I would guess it requires more equipment. Plus growing them on Lunar soil means eventually you get some elements from the Lunar soil itself and do not need to have full recycling otherwise, which means you don't have to have a fully closed cycle for this.
There is still the issue of the closed cycle for air though (which is where Mars is easier than the Moon for medium term colonies).
I'm not an expert, but as a lay person I agree with you.
However, I'm guessing people running these experiments are just looking at all the options. Hydroponics is pretty much a solved solution, no? I suppose it makes sense to run these experiments to prove what we already know. I suppose there is a hyper slim chance that lunar soil was somehow beneficial for the plant and made growing easier.
I think the nitrogen issue is probably secondary to the water issue. Hydroponics use way less water. Water is heavy and expensive to ship to the moon. Anything to reduce weight will probably be the priority.
I don't see how shipping more soil and more water would be better than hydroponics, but sometimes we write papers for problems we don't have yet, but might have in the future. Some moon colony might be struggling for physical space and need to use soil to grow supplies in an emergency? Might be nice to know they can reserve some moon land and follow these guides to produce food in the soil.
My wife got her PhD in Physics and one of her favorite anecdotes is the critical piece of technology that made her project possible was derived from a mathematical paper written 200 years ago. The dude didn't have the technology or science to know where his math would be useful, but he published it anyways. Eventually, someone needed it and found it useful.
I don't think we'll be shipping water to the moon.
Fortunately it has plenty.
Moreover, it's easier to ship energy sources (e.g. nuclear, which today are small heat generators) and use that energy to get to the water that's there.
I wouldn't ve surprised if there have been numerous studies of how to get full-scale nuclear generation going on the moon, by launching a reactor in modules. I anyone has a link, I'm curious to see what approaches have been considered regarding launching a core, safely.
The one thing the moon does have, thankfully, is water. That means oxygen, water, and hydrogen are provided once you're there as long as you have power. Essentially, the whole point of colonizing the moon can be seen as a source of water outside of the gravity well for engine reaction mass, radiation shielding, and oxygen. Nitrogen and carbon, unfortunately, you gotta ship, though you can get both by recycling it from pee and the air respectively. That's why I mention hydroponics, because getting bioavabile nitrogen from pee is a chemical process.
Granted, I am a nurse. Botany and hydroponics are not my wheelhouse. These regolith experiments people keep doing just seem to be going the wrong way.
No farming on the moon. No mining either. Leave the moon and planets alone. Until we have proven that we can fix Earth, don't go around trashing the solar system.