Nagoya, Japan — Kunihiko Murai was once an outcast in the tiny Japanese village of Jyushiyama - the worst farmer in the community. Today, the burly, ruddy-cheeked farmer is Japan's prophet of hydroponics, the science of growing plants in water solutions. In the process of turning his back on the soil, he has become a millionaire.
His farm, some 10 miles from the industrial city of Nagoya, erupts with plastic ''airdomes.'' Inside these bubbles in tanks of water, Mr. Murai creates the environment to produce almost monthly crops of spring onions, parsley, or tomatoes, for example.
Murai is campaigning to change Japan's ideas about food and farming. Why, for example, should farming be considered purely a rural occupation? Hydroponic farms could be located on building roofs in the cities, he suggests, or in multilayered giant towers.
For this, he produces drawings: supermarkets where tomatoes grow on the ceiling and strawberries on the walls; giant transparent farm capsules in the sky, with the space underneath used as a park, sports stadium, or cultural center; restaurants where patrons can pick their own fresh salads.
In an interview with the Monitor, Mr. Murai recalls his early days when, as a teen-ager, he was expected to carry on his family's longstanding occupation of farming the land. But he felt there was no vision in conventional farming.
Comparing notes with friends who work in factories, Murai wondered why industry's constant search for high technology could not be applied to growing food. He was no expert. He simply was looking at the problem from the point of view of a farmer trying to grow good crops to make money.
Of course, he knew about hydroponics because the concept has been around a long time without gaining much acceptance. And while roaming the fields and rivers around Jyushiyama, Murai gradually worked out his experiments.
In 1966 he placed a hundred tomato plants in a water bed. Ten grew ''extraordinarily well.'' Consulting every available book, Murai could find nothing like them. Each plant was loaded with better tasting, juicier fruit, produced in far less time than those grown in soil.
It was enough - ''if only one plant had been outstanding I would have known I was on the right track'' - and the next year he expanded the concept to 1,000 square meters.
The basic technique of hydroponics is to plant a seed in a small cube of sponge. After about a week, when delicate roots poke through the bottom, it is transplanted into water-filled tanks, containing a nutritious ''soup'' of 16 to 18 different chemical fertilizers. The only other ingredients needed are oxygen and sunshine (although experiments with artificial light have also proved successful).
At this stage, farmer Murai was concentrating all his energies on the hydroponic experiments, neglecting the conventional farming side. Laughing, he recalls: ''All those around me were getting on with the job of soil farming and making money. I became a bit of an outcast because I was regarded as the worst farmer in the village. . . . I had to come up with something to avoid being a loser.''
The second tomato crop was a great success. Other farmers took one look and said: ''That's marvelous. . . . Please teach us.'' Murai obliged, leading to the formation of a national research center that has so far converted 800 farmers to the cause.
Why not more? Blame rural conservatism. Says Murai: ''They think of farming as something old, primitive, and dirty, to be done on the cheap. A lot of farmers aren't interested in the job anymore, doing it simply because the family owns the land or they are eldest sons who have to take over.
''But farming should be highly scientific, something complicated and exciting.''
There is resistance in Japan to radicalism of any kind. And Murai does not cater to this resistance by his whimsical attempts to make eating more fun by producing ''fashion foods'' - using molds to make, for example, heart-shaped cucumbers and dice-shaped melons.
A Ministry of Agriculture spokesman agrees there is still a lot of skepticism about hydroponic farming. ''Everyone is trying to grow bigger and better crops, but somehow dispensing with soil altogether is still a bit too adventurous.''
Another reason for the reluctance: spending up to $100,000 to set up a 1,000 -square-meter plot for growing such crops as parsley, spring onions, melons, cucumbers, and tomatoes.
But, pointing to the luxury houses of local farmers who follow his technique, he adds: ''The whole idea is that you are growing all year round and harvesting constantly. Most people get their money back in two to three years, some can do it in one year.''
Ideas may change when hydroponics comes to mainstay crops such as rice, wheat , and corn. Murai has grown all three experimentally and claims there are no technical problems.
''It's a matter of cost. But you can do it if you plan for five crops a year. Using this method you would only need one-fifth the land now planted with crops, and you could use the other four-fifths for something else.''