On Sunday, June 26, 2016 at 10:02:46 AM UTC-6, a425couple quoted, in part:
> Can we grow food on Mars?
Lunar material was found to be good soil in which to grow plants, although of
course one would have to fertilize it from scratch.
I can see _one_ reason why this might not work as well on Mars.
Mirrors to concentrate sunlight, domes to keep the air in - or even systems to
reflect sunlight into underground caverns, if radiation is too much of a
problem - are easily enough achieved. Yes, an underground chamber would be a
big heavy engineering project, but if it's needed, the supplies can be sent to
Mars.
But one would expect to _at least_ be able to use the Martian soil. Mars also
has a lot of water, we now know. Pemafrost is messy to deal with, but it can be
dealt with; extracting water from muskeg is not worse than extracting oil from
the tar sands.
Mars is short of nitrogen. That will have to come from Earth. Eventually, once
a space presence of the appropriate type is established, it could come from
comets.
But Martian soil is obviously not good for one thing. It's not good for making
optical glass. It has *lots and lots* of iron in it.
Bad news for the Martian optical industry, even a little iron makes glass green
instead of clear.
Bad news for the Martian semiconductor industry - iron is a particularly bad
contaminant when making silicon microchips.
I don't know how iron in soil affects plant growth, but I suspect it could also
cause problems there.
John Savard