Quoting from the post above:
"And we three are not alone. David Blume writes:
On approximately two acres— half of which was on a terraced 35 degree slope—I produced enough food to feed more than 300 people (with a peak of 450 people at one point), 49 weeks a year in my fully organic CSA on the edge of Silicon Valley . If I could do it there you can do it anywhere.My point is not that everybody gets yields like this, but that yields like this are not exceptional. Do they take place on a larger, continental scale? Yes. Sharashkin, Gold, and Barham, “Sustainable Growing Practices in Russia,” University of Missouri – Columbia:
In Russia, microscale ecofarming is an extremely widespread, time – tested practice. Despite the minuscule size (600 m 2 ) of individual plots and absence of machinery, cultivators have demonstrated exceptional productivity, producing more potatoes, vegetables, berries, fruit, milk, and meat than commercial agriculture’s output of these products. Currently, with 35 million families (70% of Russia’s population) working 8 million [hectares] of land and producing more than 40% of Russia’s agricultural output, this is in all likelihood the most extensive microscale food production practice in any industrially developed nation.So, 35 million into 8 million hectares is a bit less than a quarter hectare per patch, or an eighth of an acre (my size). And they get very good yield. (These numbers also suggest that my friend, David Bruce, and I are in no way exceptionally skilled.)
So, do these numbers scale up globally? On the back of the envelope, they do. From Prairie Soils & Crops Journal [PDF]:
In July 2009, the world population reached 6.790 billion and the global arable land area is estimated as 1.351 billion hectares (3.339 billion acres). This implies that arable land per capita on a global basis is 0.20 hectares per person (0.49 acres per person).So, if Big Oil and Big Ag vanished from the face of the earth tomorrow — as perhaps, for the sake of mitigating climate change, they should do — we at least have the arable land to support 6.790 billion of us, on the back of the envelope; and if we consider I could support myself on 0.125 acres, and the Russian yields come with a growing season of around three months, we could have considerable margin. (See also here, here, and here.)"
I suggest reading the whole post for those in class interested in this issue as this small portion doesn't do justice to it.