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GLOBAL AGRICULTURE : Technology : Improving on Ways to Live Off the Land : Farmers are combining innovation and tradition to create sustainable systems that yield better production but no damage to resources.


SANTIAGO, Chile — On the rugged, rainy island of Chiloe in southern Chile, impoverished rural communities fight a never-ending battle against a fungus that can wither potato plants and turn harvests into heartbreaking failures.

But since last year, many Chiloe farmers have a new weapon in their fight against blight. They have learned how to make an anti-fungal "tea" by draining liquid from compost and adding casein, a milk protein, to stimulate the growth of certain bacteria. When the organic brew is sprayed over potato plants, the harmless bacteria shields the plants from the fungus.

The anti-fungal tea, developed by European researchers and introduced in Chiloe by Chile's Education and Technology Center, a non-governmental aid agency based in Santiago, is an example of how innovative technology can help farmers control plant diseases without costly and polluting chemical treatments.

"And in addition, this works as a foliar (leaf) fertilizer," said Raul Venegas, a director of the center.

Since ancient times, farmers have combined tradition and innovation to improve agricultural methods and plant stock. Call it Green Evolution. But today, as growing populations put new strains on agricultural land and the natural environment in many countries, it is more important than ever to keep the Green Evolution going forward.

Not only must the land be made to produce more, it must be done in ways that will not damage natural resources and reduce future productive capacity. Use of chemicals is limited. The catch phrase for that concept is "sustainable agriculture." In Chiloe and elsewhere in South America, people are working to develop the concept, introducing new agricultural technology as well as rescuing traditional techniques that have been neglected or forgotten.

In the central highlands of Peru, potato farmers have been learning how to fight the dreaded Andean potato weevil with a combination of old and new techniques. The International Potato Center, based in Lima, and half a dozen non-governmental aid organizations are working with villagers to promote anti-weevil strategies that sharply reduce damage to potatoes without using dangerous and expensive pesticides.

The methods include the innovative use of a fungus, harmless to humans, that repels the beetles when it is applied to potato storage sites. The fungus can be cultivated in homemade containers and is often used in combination with branches of the insect-repelling muna and lantana bushes.

To help break the weevil's productive cycle, farmers also store potatoes in diffuse light, which discourages insect infestation, and turn chickens loose on ground where potatoes have recently been piled. The chickens eat the weevil grubs. In some communities, the strategy has reduced weevil damage to potato harvests from 60% to 5%, according to the potato center.

A center spokesman said the strategy spreads rapidly once a few farmers in a community learn about it. "They choose what they like and they in turn teach others," he said.

Around Lake Titicaca, on the highland border between Bolivia and Peru, farmers are rehabilitating ancient agricultural systems of raised fields and canals called camellones or waru warus. The waru waru canal networks deliver water for crops in the dry season and provide drainage in the rainy season, when much of the lake basin's flat land would otherwise be boggy and unsuitable for farming.

The long, narrow planting "platforms" are flanked by parallel canals. Water from the canals seeps into the root bed from the sides. Rich organic muck from the bottom of the canals is periodically spread on the raised fields for fertilizer, making synthetic fertilizer unnecessary. Meanwhile, the canals are believed to work as moat-like barriers against invading bugs.

The water in the canals absorbs and stores the sun's heat, which, at night, can spare crops from frosts that are common in the Andean highlands.

Radiocarbon dating has indicated that these ingenious agricultural systems were producing abundant crops of potatoes and native Andean grains up to 3,000 years ago. But they fell out of use centuries ago.

In the 1980s, development projects in Peru and Bolivia began helping a few impoverished communities rehabilitate the systems. Tracing the tenuous outlines of canals filled with the sediment of centuries, farmers dug them out and used the excavated dirt to rebuild the platforms. Potato crops grown on the rehabilitated waru warus sometimes have been spectacular, many times normal tonnage yields for highland farming. Much of this land is unsuitable for any planting without an irrigation-drainage system.

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