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Agroecology -- An alternative to herbicides and genetics
by Rebecca Roberts
November 20, 2000


The Green Revolution in agriculture, which began in the 1940's and hit full swing in the 1960's, employed specific techniques: focusing on a few key crops, and heavy use of pesticides and chemical fertilizers. Those techniques successfully averted mass starvation a generation ago. But now, green revolution practices are threatening the food supply for future generations. One of the promises of genetically modified food is that it helps minimize the need for pesticides and fertilizers, and may help reduce the threat to future food supplies. But opponents of GM food say that solution poses more problems than it solves. In the third installment of our series on genetically modified food, Rebecca Roberts visited a farm where an alternative is being tested..


It's an unlikely place for a farm -- this vacant lot at a busy intersection just off the highway east of San Francisco. And it's unusual looking, too -- no neat rows of uniform vegetables, but several different plants all mixed in together. Colorful flowers sprout up between the vegetables. Clover covers the ground. But there's method in this madness -- and it's the method of Chilean born Miguel Altieri, a professor of environmental science at the University of California at Berkeley.

Altieri: So what we do here, we're doing experiments where we're mixing the cauliflowers, for example, with fava beans. And fava bean is an important plant because the fava bean is legume that fixes nitrogen. So therefore by fixing nitrogen they can connect with the roots of the broccoli and therefore do a transfer of nitrogen into the plant and you don't have to use a chemical fertilizer.

It's called agroecology -- and it's not new; in fact, it's been used by small farmers for centuries. The premise is that every challenge in agriculture can be met with a natural, organic solution, instead of fertilizer, pesticides, or the new kid on the block, genetic modification. Does your cauliflower need fertilizer to get nitrogen? Plant it next to fava beans, which trap nitrogen. Is your tomato crop plagued by aphids? Surround it with cosmos flowers, which attract hoverflies, whose larvae feed on aphids. Plagued by low yields because of weeds? Plant clover before your intended crop. There won't be any room for weeds to grow. But agroecology is hardly a simple approach. Even Altieri's half-acre plot needs careful and constant attention from a group of dedicated graduate students.

Altieri: These systems are a little bit more complicated to manage, they're more information intensive, and you have to take care of a lot of the management requirements of the crops. So they're much more information intensive, rather than input intensive. And many farmers don't have time for this sort of thing, so they go the easy route, which is just plant one thing and spray according to instructions and then you don't have to worry about anything.

You have to worry about a lot in agroecology, and that may be what keeps it from being a practical alternative to the promise of genetically modified seed. For agroecology to work, farmers need accurate information about the impact of planting one crop next to another. With GM seed, you simply buy it and plant it. Richard Manning, author of "Food's Frontier, the Next Green Revolution", describes how local biologists in India developed a genetically modified chickpea, a major source of protein in the subcontinent.

Manning: The biggest problem, the reason that the average Indian has about a third of protein he ought to have is that there's an insect that attacks their chickpeas. So these three middle aged women, figured out a way to take a gene from windbean, that confers a natural resistance to that insect. And they put it into that, and then they distribute the seed free to the people in their country. And that will increase the protein content and decrease reliance on insecticides. I really can't find a downside to that.

Manning considers himself an environmentalist, and began the research on his book expecting to disagree with GM food as a solution to the negative aspects of the green revolution. But the more he studied it, he says, the more he began to see GM as a practical alternative.

Manning: Agriculture is probably the greatest environmental damage that we do on the planet. And that's been true for ten thousand years. We've done incredible damage with green revolution technologies like chemical fertilizers, like pesticides, like irrigation. And so in that context, if we can view some limited public interest genetic engineering as a way to take the hard edge off those other technologies, then I think it's appropriate.

Miguel Altieri disagrees. Not only do genetically modified crops pose unforeseen environmental threats, he says, but over time GM can squelch any alternative farming methods.

Altieri: On the one side you have contamination with pollen for organic farmers, which is a problem. But then the other problem is that when the insects are exposed to that toxin become resistant, then those resistant insects will move to organic farmers fields, and organic farmers will not be able to control them.

The growing use of GM seed is obvious even at Miguel Altieri's experimental farm. He shares his land with a genetically modified corn project funded by biotech giant Novartis. Last year, anti-GM protesters destroyed the corn crop, but left Altieri's agroecology experiments untouched. This year, the high tech corn crop is protected by guards and security cameras. Altieri worries that the pollen from the GM corn may contaminate his experiments. But on a larger scale, he's concerned that in the rush to embrace new technologies, traditional farming techniques will be lost.

Altieri: Unfortunately today I think that modern scientists look at traditional farmers as ignorant and people that don't have much idea. I think that that attitude is very wrong. Because the key to developing sustainable farming systems for the third world lies in the indigenous systems that unfortunately modernity is destroying. And we need to rescue that knowledge very very quickly before it's lost.

And that's what Altieri is trying to do. He has no illusions that he's going to transform modern agriculture as we know it -- instead he works with non-governmental organizations to teach his techniques to struggling farmers in the developing world. His current project is in the Dominican Republic, where he's sharing techniques for controlling soil erosion during hurricane season. For the World, I'm Rebecca Roberts.


copyright Exploratorium 2001