http://www.thehistorychannel.co.uk/site/tv_guide/HD_full_details/Technology/programme_3276.php

Or buy it at: http://store.aetv.com/html/product/index.jhtml?id=76707

You ever fly over the midwest and see all of those huge circles?  Obviously they are farm areas, but why circles? 

And what does it have to do with Mars?

Watch this Modern Marvels and pay close attention to the section about Nebraska.  There's you answer about what the circles are... so what does it have to do with Mars? 

Listen closely for the mention of how all of those center pivots have already started noticably dropping the watertable and have - no doubt about it - directly played a part in diminishing the pre-historic underground lake that made the midwest 'a food basket for the world'.

Further, listen for how water brought up does not just trickle back down... plants harvested and sold take water with them and also rain and runoff are not enough to replenish the water table.

Farmers want to grow things and have to do so on a huge scale to supply the needs of the population of the planet.  The Nebraska areas are a major supplier.  Farming can't be stopped, can't and shouldn't. However, the resources required are slowly but very surely being used up. 

What's it got to do with Mars?

The demand will not stop.  The supply has to come from somewhere. 

*What's it got to do with Mars, already?*

This

Water is on Mars.  Compared to the Moon it's positively raining (so why again are we going back to the moon, besides uranium and a nice missile launching location?)

What's more Mars has been proven to not only be able to grow terrestrial plants but that its gravity and co2-heavy atmosphere is actually Better for C3 and C4 type crops (from corn to pineapples) than our Earth gravity and atmosphere. 

Now, you may, as I did, say 'whadya mean proven?  The dirt is no way going to support plants, it's volcanic iron rubble'

Ah... not quite so easy.  The Viking mission reported the chemical / plant nutrient makeup of the average Martian soil to be a lot more agrosuited than those knee-jerk thoughts.  Nitrogen was not found in Earth-average supply (which is something that has to be worked out... and logical and established methods appear to be available) but the rest is right in the health range.

Or so I was lead to believe.  Page 142 of The Case For Mars shows the table of Mars nutrients and that section of the book details the possibilities.

But Zubrin is persuasive on so many points that it can almost make you think 'this has to be too perfect' so I went looking to see - taking care to NOT use anything Zubrin related in the google - if all of the more recent landers and probes have changed the Viking stats.

And from the really-recent I got a surprise.  An article in the October 2007 Journal of Agronomy and Crop Science that detailed the results of the University of Adelaide's experiments (yes I paid for it, and if you're interested you might find it worth the $40 too) .

Huh.  Is it me or are points starting to add up?  Mars as a breadbasket?  Sounded scifi before but now...  They said we'd need 'more globes' to supply the needs of this one?  It actually does look like there is extra globe #1 and it is within actual reach. 

But is is cost effective?  It can't be, right?

So far the only popular notion working models on the ecomonic viability of food from Mars are back in Zubrin ... and he makes extremely logical points for it really being cost effective.

I hate to say that but here's the reality of it:  So far, in looking for backups to the things he proposed the later research has proved his Case For Mars case over and over.  So I'm inclined to give him more benefit of the doubts than I was before.  (While always wary of the fake-fakes)

Watch that Modern Marvels, watch for those parts I'd mentioned.  Then go back and hit that Seattle Times / NY Times article again.

Neither the article nor the documentary is talking Mars, but they both pose the question of 'where are we going to get the food that we need?' and the answer when you put both questions together is...?

Yep.