The emotional wellspring of James Duke's Magic Mountain is the venerable Cerro Pirre, deep in the rain forests of Panama, a peak he has climbed some 10 times and the place he spent the best years of his life, looking for medicinal herbs. A subtropical version of Ol' Magic could well be in the southern United States, possibly at the Alabama end of Appalachia, where Duke was born 54 years ago. But his vision is best suited for those areas of North, South and Central America where there is never a frost and the annual rainfall is at least 80 inches--what he calls the "Tropical Moist Forest Life Zone."

There Duke foresees densely planted hillsides whose productivity far exceeds the bumper harvests of today's record-breaking American farmers, a cornucopia of plenty that will bring a good life surpassing the best today's world has to offer.

Broad of beam and slow of speech, Duke is chief of the Germplasm Resources Laboratory in the Department of Agriculture's Beltsville center. Author of several books on herbal lore from China to India to the lands of the Bible and Indian America, he raises his own herbs on a rolling six-acre farm in Fulton, Md. He calls it Herbal Vineyard. Duke's wife, Peggy, is a botanist and illustrator of his books; their son John, 21, is a land surveyor and their daughter Cissy, 18, majors in botany in college. "He has always been ahead of his time," Peggy Duke says of her husband.

Jim Duke is convinced that conventional American agriculture--what he calls "monoculture"--is doomed because it "is coasting on cheap energy" and it is "so destructive for the environment that it leads to the dust bowl." In its place, he says, something like his Magic Mountain's "multi-tiered, multi-use agro- ecosystem" will become the global ideal before the year 2000. Duke predicts that the long gasoline lines of 1973 will soon return. With a worldwide petroleum shortage--or higher oil prices--he says, something like his vision will occur.

His script for utopia begins after the farmers "come to their senses" and finally leave their ancestral homes in the flood plain, homes which, before water control projects, the river used to wash away every few years. After the farmers move from the flood plains, they will build instead on the ridges. Alluvial bottom land, fertilized by rivers, is the richest of soils, capable of yielding per acre an annual 60 tons of biomass --dry weight of vegetation. That is more than one ton of protein ("Twice what our champion American farmer now gets," Duke says) as well as 5,000 gallons of ethyl alcohol, which is the superior (and less polluting) liquid fuel used by race cars. "First you take the protein out by chemical solvents," Duke says. "Then the residues are fermented and distilled to make ethanol, which is pure alcohol."

The farmers will burn their own wood for energy in the distillation process and then return the ashes, rich in minerals, back to the soil.

But Magic Mountain's main cash crop will be oil-- and it will grow on trees. Duke's envisioned source is the orange berry of the oil palm. Duke figures that once the oil palm is bred and improved the way corn and roses have been bred and improved, one acre of it will annually produce up to 1,700 gallons of oil suitable for diesel use with a minimum of refining.

The ecosystem's second tier is on the middle slopes where groves of coffee and cacao trees grow in the shade of several species of tall, nitrogen-fixing trees. Nitrogen fertilizer, which costs 25 cents a pound today, is the critical ingredient of tropical agriculture, but many trees, such as locusts, have root nodules inhabited by bacteria that take nitrogen from air and form nitrates. Using nitrogen-fixing trees, farmers could "harvest" 100 pounds of nitrogen per acre, Duke says, and thus avoid the expensive, factory- made fertilizers.

Wood will be another Magic Mountain product. A cord of mesquite--a tree common in the American Southwest--yields 30 million BTUs compared to 25 million BTUs from a ton of coal. On the slopes, fish, ducks and azolla--a floating, pea-size water fern--will thrive on terraced fields of rice, which is Magic Mountain's food staple. The fish and the ducks feed on the azolla, which is fertilized by them and which helps keep the weeds down. The farmers can rake off the bulk of the azolla every 10 days--during which the azolla doubles its mass-- and add it as a mulch to the vegetable gardens planted near the houses.

Duke's Magic Mountaineers will raise animals for meat as well as for natural weed control. Pigs will be rotated among the alluvial farms whenever the nut grass, which is invasive, gets out of control. (A cola-type beverage is made out of the nut grass roots, called chufa by the Spaniards.) Pigs will also be rented out when someone has had enough of raising Jerusalem artichoke tubers--eight tons per acre--and wants to have the ubiquitous tubers properly rooted out.

"Herbicides can cost more than chemical fertilizers," Duke says. "If a pig can eat unwanted plants and you can eat the pig, you are saving money all around."

To control weeds on a regular basis, turkeys will be kept in orchards interplanted with peas and beans. In the water chestnut patches, crocodiles will be raised for the leather market. If harvested young, the crocodiles do not thrash around the fish or destroy water chestnuts.

"The standard of living will be as high on Magic Mountain as in New York City," Duke says, then adds slyly: "A few hippies and naturalists might think that life on the Magic Mountain is even better."

Duke calls his ecosystem the Magic Mountain because he likes the alliteration. A scientist now spending much of his time computerizing herbs and as a bass player in the bluegrass band Durham Station, he defines magic as "people thinking with nature and producing at least twice as much as conventional agriculture."