Old Macdonald Had a Farm, but Not Like the One Merle Jensen Has Built for the 21st Century
updated 07/14/1980 AT 01:00 AM EDT
•originally published 07/14/1980 AT 01:00 AM EDT
Why do we need radical changes in farming techniques?
Because the globe is getting crowded. The current population of 4.5 billion by the year 2000 will be at least six billion—the pessimists say eight billion. The growth in food production will not keep pace unless we extend agriculture into new areas. The day will come when the world's deserts must be cultivated, including nearly 20,000 miles of desert coastline.
You envision farms on the beaches?
Yes, one of our main purposes is to learn to grow crops there. On coastlines there's an abundance of water available, but it's salt water. So we're working on halophytes, crops which can tolerate irrigation with salt water. We're experimenting mainly with members of the atriplex family, salt-tolerant bushes which have potential as animal forage and seed crops.
What about desalination of the sea water?
The technology for removing salt already exists, of course, but we're trying to make it more efficient. It's an important challenge when you consider that 99 percent of the world's water is unusable in its natural state because it's salty or frozen, or both.
What is controlled-environment agriculture?
It amounts to a kind of intensive greenhouse farming never seen before. We use diesel engines to pump in available water; it doesn't matter if it's salty or brackish. The heat from the engines warms the water and partially evaporates it, which raises the humidity in the greenhouse. This lessens some plants' need for irrigation with fresh water.
How does this differ from regular greenhouse agriculture?
You can't sustain such high humidity in a regular greenhouse. You have to let in outside air now and then to keep the nitrogen level high enough for plants to thrive. But with CEA, the diesel engines throw off enough nitrogen and carbon dioxide for the system to stay closed.
Doesn't high humidity create problems?
Yes, it makes many plants more susceptible to disease. A major part of our lab's work is developing strains that can take the wetness. For instance, the University of Hawaii cultivated a high-humidity tomato and we've had good results working with it.
What is trickle irrigation?
That's another feature of a CEA greenhouse. Measured amounts of a water-and-nutrient mix are trickled directly onto the plants from a narrow hose running the length of the furrow. This conserves precious water and you can stock the greenhouse with whatever soil is on the scene—even if it's mostly sand—and still get results. In Iran, Morocco, Israel, Jordan and the American Southwest, trickle irrigation is being used successfully in outdoor farming, too.
Aside from water conservation, what makes the new greenhouses unique?
Their efficiency. Year-round growth gives yields 10 to 40 times greater than open-field production. It is a high-density operation. We use every cubic foot of space, not just ground level.
What would a visitor see?
Well, we have one system in which we raise catfish in long tanks of nutrient-treated water. On the surface of the water we float thin sheets of Styrofoam into which Bibb lettuce plants have been inserted. On trellises straddling the tanks we grow cantaloupe. While the melons ripen, we can harvest three or four crops of lettuce. When the melons are ready, we just shake the trellises and they drop into the water and float.
What other match-ups have you devised?
We've learned to grow pole beans so that they wrap themselves around corn stalks. That way the land produces two crops at once. Another advantage to such a pairing is that the bean, because it's a legume, takes nitrogen from the air to produce its own fertilizer. It is also used by the corn, which requires extra fertilizer. This is called intercropping.
What about food for outer space?
Boeing once estimated that it would cost $500 per pound to rocket meals into space, so it will be cheaper for future colonists to grow their own. It's impractical to ship soil into space, so we're experimenting with a huge drum that revolves, creating artificial gravity. Lettuce plants inserted in the wall of the drum send leaves toward a light source at the drum's center, while their roots grow through the wall toward a nutrient mix sprayed from the outside.
Are you creating new plant types?
No, we are busy enough reviving the obscure ones. There are more than 110,000 species of plants in the world, of which about 80,000 are edible. Yet over the centuries people have used only about 3,000 species for food. Today over 95 percent of all our calories and protein come from just 30 species. Wheat, rice and corn alone account for more than half of our food energy. It's obviously foolish to rely on so few when there are so many others remarkably packed with nutrients. It's a shame they've been forgotten.
Which of these foods are most promising?
One is the winged bean from New Guinea. We call it the soybean of the tropics. Its roots have 10 times the protein of the potato, and every part of it is tasty. The beans yield polyunsaturated oil, the leaves are like spinach and the flowers, when cooked, taste like mushrooms. It's a remarkable plant, and it has now been introduced to more than 70 countries with tropical and semitropical climates.
What are some others?
The marama bean from Africa is as nutritious as the peanut, and it thrives in dry areas. The roasted beans are said to taste like cashews, and it makes a sweet vegetable. Yet it is virtually unknown and has never been cultivated. Then there are exciting nonfood plants like the guayule, which produces an excellent substitute for rubber; the jojoba, whose nut contains an oil that can be used as an industrial lubricant, and the euphorbia, also known as the gasoline plant, which produces a milky hydrocarbon that can replace some petroleum products.
What success has your environmental lab's methods had in the Third World?
Our first and probably best-known project is an air-inflated greenhouse in Abu Dhabi raising vegetables in sand with desalted water. We opened it in 1968 and within two years were growing 400 tons of vegetables a year, the highest food productivity of any desert region in the world. It took some ingenuity, though. Once, when we were trying to introduce a new long cucumber, we had the ruler, Sheik Zayed, eat one on TV. Almost the next day it was popular all over the country.
What are your hopes for your lab's exhibit at Disney World's Experimental Prototype Community of Tomorrow, scheduled to open in two years in Orlando, Fla.?
That it will give people new optimism. We'll have a six-acre pavilion demonstrating farming techniques of today as well as the methods we've been talking about. It'll include a boat ride through a simulated rain forest, a desert and an American prairie. I hope it'll inspire people to encourage legislators to support further research. We've heard for so long about doom and gloom in the world that people should know how hopeful the future is.