Roger Pielke blogs a chart on the Decoupling of Food and Land.
One of the comments references an entry on Peak Farmland by Matt Ridley from a couple of years ago.
The concept is fairly simple in that, apart from the insanity of taxpayer-subsidized corn-based ethanol fuel, more people can be fed from less acreage than used to be the case. Some of that is a function of GM crops, about which I am ambivalent. New equipment, technologies and techniques allow land to be more productive. Replenishing nutrients through fertilization is an advanced and highly informed process these days. I suppose more efficient usage of space for livestock and poultry is also a factor.
Some of this is undoubtedly good. We don't want to see people go hungry. It gives us a little breathing room to prevent starvation, but we need to keep in mind that it is very energy-intense, petrochemical-based farming. Without a ready and reliable supply of fossil fuels, agricultural land usage would have to expand, perhaps dramatically, to meet the demands of the planet's human population.
We might have seen some moderation in food prices had it not been for the inflationary policies of the Federal Reserve.
It's funny how stupid government tricks keep messing up the wisdom of a free market.