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.

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.

Archeologists estimate that in prehistoric times at least 200,000 acres of waru warus were built around Lake Titicaca, the largest lake in South America. Remains of similar raised field systems have been found in the flood plain of the Beni River in lowland Bolivia and in several other countries in the Latin American region.

While only a small sector of the ancient waru warus around Lake Titicaca have been rehabilitated so far, agricultural development specialists say the potential for the systems is great.

Elias Mujica, a Peruvian development specialist, said harvest results have proven beyond doubt that waru warus are superior to tractor farming in the Titicaca basin, where topsoil is generally thin. Waru warus conserve and enrich topsoil, while tractor-drawn plows dilute topsoil by mixing it with less fertile dirt underneath, said Mujica, who is writing a book on traditional technologies for water and soil use in the Andean highlands.

While waru warus do not require sophisticated equipment or technology, they do require careful study and planning. “If the waru warus are too high, the plants will not receive the water they need. If the waru warus are too low, plants will receive more water than they need,” Mujica said.

Crops can also be lost if the canal network in a waru waru system does not include mechanisms for bringing in water from the lake during droughts, when lake levels are low. All of this requires the cooperation of entire communities, which usually are not as well organized today as they were in prehistoric times when waru warus originally were built.

Miguel Holle, a Peruvian horticulturist who has worked on waru waru rehabilitation projects, said study is needed to learn more about how the ancient systems worked and what crops are best suited to them. “Fifteen years ago, we didn’t know anything about waru warus, “ Holle said.

Holle and Mujica work with the International Potato Center. One of the center’s latest projects is to explore ways to cultivate, use and improve several non-potato species of edible tubers and roots.

Those plants, like potatoes, were domesticated and developed over many centuries by pre-Hispanic natives in the Peruvian highlands. They are hardy, nutritious and sometimes more tasty than potatoes. Holle and other scientists believe that some of these roots and tubers once may have been successfully cultivated in waru warus-- and might be again in the future.

The Spanish colonizers of Peru discouraged the cultivation of most traditional roots and tubers, substituting European grains and vegetables. Holle estimates that fewer than 25,000 acres of roots and tubers, excluding potatoes, are grown in Peru.

While most of the plants are little-known outside the Andean region, some already have proven profitable as commercial crops in other countries. The arracacha root, for example, is cultivated in neighboring Brazil and used by the Nestle food company as an ingredient in instant soups and baby foods. It is said to be ideal for babies and other people with digestive problems because its starch is easy to digest.

Other examples:

* Achira , or arrowroot, is native to the Andes but has been grown for years in Vietnam for making noodles.

* In Japan, farmers have begun growing yakon , a root that is crisp and sweet when peeled and eaten raw. In some highland areas it is known as the “fruit of the poor.” And its fructose is tolerated by diabetics, making it a good non-sugar sweetener.

Research on roots and tubers is a key program of a new Consortium for the Sustainable Development of the Andes that is being led by the International Potato Center. The consortium is formed by about 40 institutions in Peru, Bolivia and Ecuador--mostly government agencies, non-governmental organizations and universities.

Hubert Zandstra, head of the potato center, said the sustainable development project is necessary because nearly five centuries of misuse and overuse of the Andean environment have seriously reduced its capacity for agricultural production.

“The consortium will seek ways in which farmers can use practices that do not put such a drain on the land and natural resources,” Zandstra said. In some cases, he said, that should include efforts to increase the use of ancient technologies such as the waru waru and of traditional crops such as native roots and tubers.

But modern technology can be just as crucial, he emphasized. For example, the potato center is using molecular DNA fingerprinting techniques to study the characteristics of different strains or varieties of traditional roots and tubers. Zandstra said the ultimate goal is to breed better hybrids--ones that might be disease-resistant, give bigger yields or have “certain traits that would have a tremendous market.”