IDEAS FROM ABROAD, SOME OLD, SOME NEW
This report is based on information found in
HYDROPONICS IN JAPAN
The rise of hydroponics in Japan rests upon the U.S. Army's use of hydroponics in Chofy, Tokyo right after World War II and also upon the increase in vegetable injury from micro-organisms in the soil. Today most of Japan's hydroponics is done with NFT or sand/gravel techniques. Using bio-technical approaches such as posed by hydroponics, the Japanese have come up with newer and more productive plants such as the huge tomato plant shown in recent years at the Tsukiba Expo. This plant had produced over 10,000 large fruits! It was done with extra lighting techniques.
Their number one nutrient flow technique involves slabs of styrofoam floating on the nutrient solution. Urethane cubes with implanted seedlings are inserted into tapered holes in the styrofoam "rafts". These slabs are about 1 1/2 to 2 inches in thickness, thin enough to allow the roots of the new plant to reach the nutrient solution below. The slabs are placed next to each other and form one continuous floating platform from one end of the greenhouse to the other. Thus a crop can be planted at one end of the greenhouse and harvested at the other! Small pumps aerate the liquid under the "rafts"; this gives oxygen to the root systems above. Since the rafts are tightly fitted to each other, the root systems are kept in the dark where they can flourish.
Fruiting vegetables are grown in sand or gravel and, in more recent cases, in rockwool cubes and slabs. Many Japanese growers are turning to the solid media - these are not usually interconnected and do not easily transmit disease. Japanese growers like extra artificial lighting which gives continuous growing without regard to the weather.
HYPONICS is the name of a popular system where gravel pots are set inside troughs or beds and a nutrient solution is allowed to flow intermittently through the beds. Similar to the ebb-flow technique discussed earlier, the solution is allowed to rise to the top of the pots and is then drained away. The plant is seeded directly into the pot. Air is constantly mixed with the nutrient solution as it leaves the tap. The M-method is the styrofoam raft explained above.
SANDPONICS is a system which uses drip irrigation instead of the usual flooding techniques practiced in sand/gravel beds. In this method the beds are 3 inches deep and 24 inches wide. The system allows for gravity feed and aeration. Most plants are planted/seeded directly into the bed. It now seems that the Japanese are currently more interested in recirculating (closed system) nutrient techniques than they are with sand or other media.
Hydroponics is now well established in Japan, particularly for vegetables such as cucumbers, melons, tomatoes, lettuce, honeworts, strawberries, radish sprouts, leeks and green Welsh onions. One of the most remarkable applications of hydroponics is a computerized NFT system in the Daiei supermarket which is located in Funabashi City at the Lalaport Shopping Center, one of the largest in Asia. Starting from scratch (seed!) in the back of the store, the product makes its way as it grows until it reaches the customer up front. Only four technicians control the entire process.
One technician operates the computer, the others tend the crop. Inside a 70 square yard laboratory, glass windows allow you to see large heads of lettuce in plastic beds, ready for market. The computer controls temperature, light, humidity, nutrient, carbon dioxide and water. Seeds are grown in canisters filled with water. When their primary leaves begin to show, the technician place them into one inch cubes of rockwool (horticultural or agricultural). The plants are kept separate from the main growing room until they have about five leaves. The seedling is then plugged into a hole on the plastic board where it will grow until harvest time. With all its plants now intact, the board is taken to the main growing area and allowed to float on a nutrient bath solution. Almost like a conveyor belt, the board floats and moves upon the nutrient solution. What normally took 80 days or more to get to harvest now takes about 35 days.
Though the system was copied from similar ones in Denmark and the U.S., the Daiei supermarket uses only artificial lights to grow crops. Such systems in other countries use both artificial and natural light. This combination of lighting is becoming more popular in the U.S. With artificial lights only, electricity comprises half of the total costs of production. Even with the higher costs of electrical usage, the vegetables grown are sold at only 2-4% higher price than those grown in traditional ways. It seems Japanese housewives don't mind paying extra if they're certain they're receiving highly nutritious, clean lettuce. The supermarket grows five different kinds of lettuce and is considering other vegetables for the process.
This is the only known supermarket which has gone to such drastic means to insure quality to its customers. Two large Japanese companies are looking for ways to improve on the system and export it to interested parties. This kind of hydroponics is very useful in a country which has limited land space for agriculture. Some Japanese growers think the system can be accommodated to multi-story buildings.
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