Some interesting comments by the panel of economists at an FT blog.

The remedy to high food prices is to increase food supply, something that is entirely feasible. The most realistic way to raise global supply is to replicate the Brazilian model of large, technologically sophisticated agro-companies supplying for the world market. To give one remarkable example, the time between harvesting one crop and planting the next, in effect the downtime for land, has been reduced [to] an astounding thirty minutes. There are still many areas of the world that have good land which could be used far more productively if it was properly managed by large companies. For example, almost 90% of Mozambique’s land, an enormous area, is idle.

Unfortunately, large-scale commercial agriculture is unromantic. We laud the production style of the peasant: environmentally sustainable and human in scale. In respect of manufacturing and services we grew out of this fantasy years ago, but in agriculture it continues to contaminate our policies. In Europe and Japan huge public resources have been devoted to propping up small farms. The best that can be said for these policies is that we can afford them. In Africa, which cannot afford them, development agencies have oriented their entire efforts on agricultural development to peasant style production. As a result, Africa has less large-scale commercial agriculture than it had fifty years ago. Unfortunately, peasant farming is generally not well-suited to innovation and investment: the result has been that African agriculture has fallen further and further behind the advancing productivity frontier of the globalized commercial model. . .

Our longstanding agricultural romanticism has been compounded by our new-found environmental romanticism. In the United States fears of climate change have been manipulated by shrewd interests to produce grotesquely inefficient subsidies for bio-fuel. Around a third of American grain production has rapidly been diverted into energy production. This switch demonstrates both the superb responsiveness of the market to price signals, and the shameful power of subsidy-hunting lobby groups. . .

The ban on both the production and import of genetically modified crops has obviously retarded productivity growth in European agriculture: again, the best that can be said of it is that we are rich enough to afford such folly. But Europe is a major agricultural producer, so the cumulative consequence of this reduction in the growth of productivity has most surely rebounded onto world food markets. Further, and most cruelly, as an unintended side-effect the ban has terrified African governments into themselves banning genetic modification in case by growing modified crops they would permanently be shut out of selling to European markets. Africa definitely cannot afford this self-denial. It needs all the help it can possibly get from genetic modification. Not only is Africa currently being hit by rising food prices, over the longer term it will face climatic deterioration in the context of a rapidly growing population.

Ox, meet gore.

Another issue is the lack of property rights in Africa.

Mr Mbeki, who is deputy chairman of the South African Institute of International Affairs, said that this vision would only be feasible as long as land ownership and political accountability were addressed at the same time.

He cited Zimbabwe, where President Robert Mugabe's government has seized most of the country's commercial farms in the last eight years, as an example.

"We've seen the consequences of the farmer not having property rights in the destruction of agriculture in Zimbabwe," he told the BBC.

"Zimbabwe had a green revolution - for example their maize is hybrid maize, it wasn't just traditional seed they were using but the Mugabe regime took away the land."

I think it is worth emphasizing the cruelty of romanticism. It's merely fashion crime in Europe and USA since the net effects are comparatively small or at least affordable due to great wealth and the more advanced condition of the rest of the economy. But in Africa it is sometimes a death sentence and always a severe hardship.

Not said is that large-scale commercial agriculture is not inherently unsustainable and environmentally harmful. Peasant systems can be more so when the whole system is considered since they can't produce enough to meet demand. Such systems come apart under pressure and lose whatever virtue they possessed. History is littered with examples.

Large-scale commercial agriculture is improving in ways that make it more sustainable, and there is still a large upside, opportunities for continuous improvement. More knowledge of and attention to natural systems and their needs, coupled with increasingly non-intrusive higher technology methods and materials, shows promise of being able to meet out large and growing needs for food and fibre.

I can imagine a future where this is even more human scale, but it will be a result of non-human technologies - ag bots. Roomba for crops rather than carpets. Beyond that I suspect the bots will be replaced by engineered biological solutions. At small scales the difference between biological and mechanical systems diminishes, but I think that biological systems have a competitive advantage and there is already an extensive tool kit to speed development.