Pedro Sánchez won the World Food Prize in 2002 and a MacArthur Foundation award in 2003 for his pioneering work in raising food yields in developing nations. The director of the tropical agriculture program at Columbia University's Earth Institute, Sánchez is also co-chairman of the Hunger Task Force of the United Nations' Millennium Project, which has set ambitious targets for reducing poverty, hunger, disease, illiteracy, environmental degradation, and discrimination against women by 2015. Sánchez spoke recently about his work with Elizabeth Royte.

Why should people in the United States care what happens to African farmers?
Land resources are more threatened in Africa than anywhere else in the world. There is very little forest left outside of the Congo basin. The loss of biodiversity has been tremendous. And environmental destruction equals poverty. The people who can fix the problem are the farmers. They're the ones in charge of the biggest chunk of arable land.

You won a MacArthur fellowship in large part because of your work with agroforestry -- improving food crop yields by planting trees. How does that work?
When you plant leguminous trees such as peanuts and peas and other fast-growing trees after a corn harvest, they take tremendous quantities of nitrogen from the air during the dry season and make it into useful nitrogen in the soil. In Kenya, I'm aware of maybe 150,000 farm families who say they are no longer hungry as a result of this approach. The trees also provide an important secondary benefit, which is firewood. About one acre of fallow land produces sufficient firewood for a family for a year. So that eliminates long treks for women who have to go to the bush and carry back enormous loads of firewood -- which also depletes the remaining biodiversity.

The first green revolution led to an enormous increase in food production, but at a very high environmental cost. Could that happen again in Africa?
The original green revolution of the sixties and seventies was one of the most amazing achievements of humankind in the last century. Production tripled in the developing world. In India, 200 million people were going to starve to death, and now India is a food exporter. But in those days we weren't conscious of environmental issues. Fertilizer was so cheap, especially in the United States, and we applied too many pesticides to control insects and diseases. Forty years later, we know a lot more. We know the importance of organic fertilizers, of zero or minimum tillage to decrease erosion, and of plants taking carbon dioxide from the air and sequestering it in the soil, not only to negate global warming but as the basic energy source of microorganisms. We've learned that there are beneficial bugs, that not all bugs are bad. So the kind of green revolution we are advocating in Africa now is one that is ecologically sound.

Still, some environmentalists criticize you for favoring the use of genetically modified seeds in Africa.
Quite a bit of Bt [Bacillus thuringiensis] corn and cotton is being cultivated in Africa right now because it cuts down on insecticide use, just as it does here. So far, the scientific evidence shows no detrimental effect from genetically modified crops that hybrid crops have not shown. This is very important. In an open-pollinated crop like corn, with separate male and female flowers, the male pollen, like a sperm, has to reach the female flower. It's wind-dispersed. So it can fertilize some of the native female corn flowers. But that has been happening since we've had hybrid corn, for almost 90 years. My emphasis is on using biotechnology and conventional breeding for traits that the poor like and need. The poor do not need [Monsanto's herbicide-tolerant] Roundup Ready soybeans. But they certainly could use a drought-tolerant corn. And there are some important advances in conventional breeding and biotechnology that seem to be headed in that direction. In India, which has a lot of saline soils, breeders are putting genes of mangroves, which grow in saltwater, into rice to make it salt-tolerant.

But how can farmers be self-sufficient if they need genetically modified seeds?
We're not going for self-sufficiency. We're going for ecologically sound, profitable farming. I want the woman with five kids to be well nourished and get out of poverty. But you're not going to get rich. I don't care how much corn you can grow on one hectare of land. It just isn't big enough.

What if all that woman wants to do is to feed her family?
She wants to get rich! There's no lack of motivation here. Some of these farmers in Kenya suddenly realized they could put only part of the farm into corn because it was yielding three times as much per hectare. So they planted kale, onions, and tomatoes that they could sell to the markets. They began to make money. Then they diversified and got a milk cow, and that changed everything. We have farmers now who have two or three cows. They sell the milk to their neighbors and they're making money. They're even selling manure.

Your recommendations have implications beyond individual prosperity, don't they?
Getting these people out of poverty and making them trading partners is good business for everyone. We're turning them into consumers. And we're talking about a market in Africa of about 800 million people. But it's not just economics. In a globalized world the poor can watch CNN and see how well others live; this is a cause of unrest, and of migration. To address the root causes of terrorism you have to eliminate poverty. So increasing agricultural production and eliminating poverty is good for everybody. It's good for business. It's good for security. It's also good for us to feel like human beings, and that's one of the reasons I got into this business.
-- Elizabeth Royte