What's the least amount of land that will support a family of 4?

I was reading some forum someplace, and there was a question posed which I thought was interesting:

"How much cropland and stock animals required for US family to sustain itself?"

And while that's an interesting question, it's pretty big.  Like, how do you account for the cotton in the clothes you wear, or the leather in your shoes, or the rare earths in your cell phone, or any of the million other inputs we all have in our modern life.  The fact is, the typical american requires this entire planet to live like we do.

So I'm going to go for a simpler question:

What's the smallest area of land that can provide food for a family of 4?

The first thing to do is figure out how much food we need.  For most folks, a 2000 calorie diet is good; kids eat a little less, adults a little more.   Modern corn varieties yield 2.47 tons per acre; you'd need about 450 pounds of corn per person per year... so your family would need about 1800 pounds of corn.  I'm going to round that up to 2000lbs to account for wastage and rodents.

Now what kind of life would that be?  Well.. it's actually how quite a few people in africa live right now.  When I was traveling in Zambia and Zimbabwe in the mid-90s I ran across quite a few tiny farms that had their corn patch, and the primary, staple food was a corn meal mush Zambians call nsima, and Zims called sadza.  It was present at every meal, and was the bulk of the calories eaten.  Most of the time the primary goal of most of the farmers was to get something to flavor it with -- a bit of dried fish, or chicken, or some bush meat.

I mention that here because it's entirely possible that your family of four could really, honestly live entirely on the corn produced on a 3/4 acre parcel.  Catch the occasional squirrel or rat or bird for flavoring, and you're all set.

Salt helps, of course.  Everything is better with salt, but in a pinch, having your stomach full is a big plus and if it's a bit bland... well, you're not hungry.

I read variations of this question all the time on homesteading forums; and you get answers all over the boards.  Sometimes it's 2 acres, or 5, or 20, or 50...  some solutions have permanent wood lots for supply heating wood, some include animals, some don't.  

What's interesting on this is that most of the people start with the basic assumption that you're going to be able to supply from your own patch of land what we take for granted in our average local supermarket.  Sorry to say, it's not going to happen.

Subsistence lifestyles, which is the basic question posed, often mean that you have one staple crop.  rice, corn, potatoes, wheat.  And the bulk of your time and energy is spent growing that single crop.  If you manage to make enough to feed your family, then you can think about adding something to that staple crop to make it taste better.  Like salt.

Now if you're able to produce a surplus consistently, then you start thinking about things that you don't normally eat.  Like sugar.  Or spices.  Or Butter...  yes, butter is a luxury.  Think about what you have to do to produce a pound of butter.

In the dark ages people did keep cows, oxen, but the primary use of the oxen was for drawing carts and plowing.  Oxen were very hard to keep; pastures, meadows, places where hay could be cut and stored, were precious, and claimed, and you had to be pretty wealthy to own enough land to be able to support an ox, or a team of oxen.  You didn't keep them for milk, as we do now.   You kept them as your tractor.  And if you got some milk, that was a bonus.  But not the main purpose.

So if we're talking about a subsistence lifestyle, you're going to be focused on your crop.  And for corn, that means you're out there with a bucket watering it.  And a cane chasing off the deer.  And with your hands picking the bugs off it.  Because corn (or wheat, or potatoes, or rice) IS your life.  Without it you'll cease to exist.  Keeps you pretty focused.

And planting corn becomes pretty important because corn doesn't really keep very well; it's not like wheat that can go for thousands of years and still sprout.   So every year you have to have a good harvest, and you have to put enough of that away that you can replant.

And when you plant corn becomes really important.  If you plant it too early, it may die.  If you plant it too late, it may not ripen.  And if it's not ripe at harvest, you have nothing to plant.

And you start seeing why all of the ancient corn civilizations got really, really good at astronomy.  They used the stars to tell them the seasons, and when to plant, and how long they had.  The weather wasn't reliable enough, but the stars were.  And you can see exactly why they had to know.  They would cease to exist if they made the wrong decision in any given year.  Huge pressure.

The early contacts in the americas between european settlers and native tribes ended with reports from them that each tribe that grew corn would usually have a 3 year supply of it in their village.  If the crop didn't work out this year, they'd just dip into the surplus.  This sort of "sloth" on the part of the tribes struck the early settlers wrong, and there are many accounts of attacks on the indians storehouses to destroy the surplus, to get the indians to work harder.

But there's a reason for a reserve.  Right now, our society uses virtually all of the corn we produce every year, for one thing or another.  Ethanol, animal feed, raw material for various products, and food for humans.  So we do have a surplus in a sense -- if our corn supply falls below some level, there are things we can reduce to provide more food for humans.  But when you look at it on a global scale, we don't have anything like a 3 year supply of food.  I've heard it said that we've got on average, a 3 day food supply in every city in america.

So we're three days from a subsistence lifestyle.   Do you own a hoe?