Simon Maxwell of the Overseas Development Institute chairs the session with Paul Richards of Wageningen University and Pedro Sanchez, director of the Millennium Villages Project, The Earth Institute at Columbia University.

Sanchez is first up, talking about the African Green Revolution and the Millennium Development Goals, which his Villages project suggested a budget of $110capita/yr to achieve in rural Africa.

At Addis Ababa in July 2005 Kofi Annan called for a Green Revolution for Africa, with agriculture at its centre but with nutrition, making markets, politics and sustainability at its core. And what happened? Sanchez gives Malawi’s experience as an example with a 75% subsidy of fertilisers resulting in an increase of maize production and yield doubling for some small farmers.

The Villages idea captured the idea of philanthropists and raised $150m in six months, resulting in 12 Millennium Villages in Africa. The idea behind the villages is that communities need to be empowered with science-based innovation while tackling hunger, disease and water are the priorities.

Food aid from the US costs $670/ton, locally produced food costs $240/ton but using fertiliser and seeds it costs $77 to produce an extra ton of food, says Sanchez. Malaria bed nets have been used to dramatically decrease the number of malaria cases while a range of small scale entrepreneurial initiatives are aimed at getting people out of the poverty trap.

Paul Richards takes the floor now and promises to offer some real alternatives to Sanchez’s Green Revolution, in fact Richards’ presentation is called Green Revolution Or What? It’s the ‘or what’ – the bottom-up model – that he wants to talk about.

Putting “farmers first” is not enough, says Richards, who believes that we need an approach that puts engineering centre stage. He is interested in developing the theory and practice of unsupervised learning – and believes the Green Revolution is supervised learning. Believing that Artificial Intelligence research can play a central role in alternative models, Richards has been working on the notion of seed systems as neural artificial networks.

So the radical alternative question Richards proposes is whether it could be possible to engineer a genetic network for food security that does not require supervised learning.

Rice in West Africa is his example – interspecific rice (nerica and farmer hybrids). Richards says the Green Revolution induces spread of innovation by showing the seed system the ‘correct’ pattern. But an alternative can be based on unsupervised learning that already takes place, he adds, whizzing through some very big and interesting ideas very quickly, too quickly for your correspondent here to fathom, I’m afraid. So instead you can have a look at his presentation.

And so, to the questions from the floor, the one everyone wants the answer to: are these two approaches complimentary or opposing? The answer, well, Sanchez is polite and says they can be complementary, we want the best of science, whatever that is, says Sanchez.

Richards says he’s talking about organising a network of scientific investigation involving poor people themselves, not about laboratory science. Pressed by Maxwell to say whether he would close down the Villages project Richards says no, there is a role for it. Again, maybe not the answer people were expecting. Financing and incentives and institutions are the things that need to be looked at to make sure that there can be some collaboration.

Robert Chambers of IDS tackles Sanchez about the Villages project, acknowledging the energy and enthusiasm of the project but appealing for alternatives that could spread much more quickly.

Maxwell says that the Villages project is the overwhelmingly successful policy narrative of our day, and if we don’t agree with it then we have to come up with something else. One delegate asks if Villages is a classic 1960s policy, and Sanchez does agree that it is ‘back to the future’, but says: “We are learning, but we cannot wait around. Human poverty can be stripped out in Africa, there are things coming in to place that I have not seen in my entire life and we have to go forward and we can win.”

Richards says he is in favour of the Villages project but wants it to be monitored so there can be some learning at the end of it.

Maxwell urges delegates to keep on with this debate through the Future Agriculture Consortium (an affiliated STEPS project) among other things.