Seth Borenstein has the lowdown on the planet's dirt problem. Yes, there's a dirt problem:

As seeds get better, much of the world's soil is getting worse and people are going hungry. Scientists say if they can get the world out of the economically triggered global food crisis, better dirt will be at the root of the solution.

Soils around the world are deteriorating with about one-fifth of the world's cropland considered degraded in some manner. The poor quality has cut production by about one-sixth, according to a World Resources Institute study. Some scientists consider it a slow-motion disaster. ...

A generation ago, through better types of plants, Earth's food production exploded in what was then called the "green revolution." Some people thought the problem of feeding the world was solved and moved on. However, developing these new "magic seeds" was the easy part. The crucial element, fertile soil, was missing.

The situation in sub-Saharan Africa—where nearly one million square miles of cropland is rapidly eroding—helps make the point. In theory, genetic improvements to corn should make it possible to grow 9,000 pounds per acre, but many Africans only manage 500 pounds per acre, thanks to poor soil conditions. Fertilizer can provide a short-term fix, but even that's in short supply in many countries. (Malawi's one notable exception.) Sadly, most aid donors don't spend a lot of time thinking about how to make better dirt, so the issue usually gets short shrift.

What about the long term? I'd imagine sustainable farming techniques will have to play a bigger role. That seems to be the conclusion of the UN's recent 2,500-page report on global agriculture, at least. In a similar vein, this old piece in the Seattle Post-Intelligencer notes that the United States is quickly running out of topsoil, too, and explores a few potential conservation strategies (no-till agriculture and organic farming, in particular). Anyway, seeing as how we have a number of commenters that know far more about soil than I do... what say you?

--Bradford Plumer