Jessie Quill wrote:
Farming is a very interesting topic. In reality, there are actually quite a few ways to make soil viable to grow foodstuff in.
The question I was trying to keep in mind is, what ways are there to make
Martian soil viable. Which is like if you had a volcanic island that had just risen out of the ocean and was immediately enclosed in a force-field that kept all life out except what you carried in on your boat, including plants, animals, birds, and even bacteria and fungi. Except that Mars is millions of miles away, and you have to pay to get anything up to Earth's escape velocity before you can even aim for Mars.

Jessie Quill wrote:
To keep it fertile, you can:
-Set up a drip system that circulates irrigation water between a fish tank and the soil, whatever water doesn't get absorbed by the plants drains back into the irrigation. The fish release whatever they release into the water, then that goes into the planters and the plant/soil filters it to make it clean and go back to the fish. You can do this with hydroponics or soil.
While interesting ... it doesn't seem like this would scale all that well. The more soil you're trying to treat or plants you're trying to grow, the more water you need ... and the aridity of Mars is one of the main constraints.
Jessie Quill wrote:
-(This might seem obvious but is effective if you know what you're doing.) Make compost by having a bin for organic waste and fill it with a ton of Earthworms. They'll break the garbage down into soil. You can do it without Earthworms but it takes longer for the garbage to break down and isn't as nutrient-dense, as far as I know.
I've been presuming that this has been going on essentially constantly (though I'd not thought to mention earthworms, which are indeed notable), or that maybe even some genetically engineered microorganisms (or worms) were doing the conversion even more efficiently than we usually get here-and-now. But on Earth, we have marginally-viable soil to start with; the Martian environment is essentially actively hostile to life.
Jessie Quill wrote:
-If you were to use animals for compost--and you let them roam around the garden--you can easily just use small animals like chickens and turkeys.
Another constraint that I brought up before that is extremely relevant here is environment-controlled space. A "garden" has to be heated, pressurized, oxygenated (and otherwise gas-balance-corrected

), radiation-shielded, and artificially lit, even before you start thinking about soil and fertilizer. And letting an animal roam around the garden on its own---an animal you've imported from Earth (or descended from animals imported from Earth; as with most things in economics, what's at stake is the cost of replacing it, not how much it cost) at ruinous expense, around a garden that was similarly ruinously expensive ...

Jessie Quill wrote:
-BUGS. Those are easy to import. ;-)
But tricky to import just the ones you want, and then keep those
alive. Technology has advanced since the Age of Sail, when bees (and silkworms) were shipped across oceans at great expense, but the distances are orders of magnitude greater and the dangers more perilous.
Jessie Quill wrote:
Just a few examples, but I have lots of Youtube videos I can find that talk about taking very poor quality soil and building it up into rich topsoil on a large scale.
One of the points I've been trying to make is that Mars makes "very poor quality soil" look like "rich topsoil" in comparison, while every such process I'm aware of uses resources that are freely available on Earth (sunlight! heat! air rich in oxygen and nitrogen!) or fairly cheap to purchase and transport in bulk ... none of which is readily available on Mars except at
very great expense.
Though I willingly admit everything I say comes from what I've read in bits and pieces over the past decade or so and has gotten rolled around in my brain, so it's quite possible that I'm wrong on some or all of my points.
(On the other hand, I'd be interested in some links, because I use this sort of thing in the development of my strategy game, Strategic Primer.)