For every dollar a barrel of oil rises, a poor farmer somewhere in the world finds he can afford less of the industrialised inputs his productivity relies on.

Marginal farmers can definitely find themselves in trouble.

The Question is: Why doesn't the price of his crop rise to offset the increasing costs of his inputs?

Here's what you often find:

(1) There is a grain surplus in his home nation. Essentially his services, as a marginal farmer, are not required. Awful, but true.

(2) He is denied access to world markets. Or, at least, denied anything like fair access. Subsidies that other rich countries use to pad their farmers' wallets keep the price too low. This is a biggie. And the developing world complains about it all the time, as they should.

(3) He faces outright price controls for his produce.

That said, my comments in previous posts apply to nations where fossil fuel use in agriculture is only a tiny fraction of total use: the developed world.

If a country uses fossil fuels mainly for agriculture, they could be in real trouble post peak. No argument there. Unless, they have completely unimpeded access to global markets (fat chance!), they would have to begin the wrenching transition to another form of agriculture, a transition that may well be a century distant for developed nations.

Another way of putting it would be: We have seen the end of cheap oil. But the age of cheap food continues (at least for now. But observe Mexico). And that's what's killing the marginal farmer.

It's also happening due to ethanol. In essence, we are diverting oil and other fossil fuels away from food to a substitute for oil. We are clearly making the judgement that our cars are more important than our food or those who would otherwise be importing our food.