No need for rice paddies…Hydroponic cultivation of rice in an indoor space is now feasible! Will it be the savior of “rice shortage”?

Rice” with a grass height of 15 to 20 cm that can be grown in a small space

The time is coming when rice will be grown indoors instead of in rice paddies.

Hydroponic rice cultivation” is becoming a reality.

Hydroponics is a cultivation method that uses water and liquid fertilizer to grow plants without soil. Since rice can be grown indoors, there is no need to worry about weather or soil-borne pests, and stable rice production can be expected.

In June this year, the Hyogo-based agricultural venture Ayuchi announced that it had developed hydroponic cultivation technology that enables high-density cultivation in a small space.

The new “Mizu-no-Yume Rice” variety bred by the company is characterized by its ultra-dwarf and early maturing characteristics, with a grass height of 15-20 cm and a cultivation period of approximately two months, and can be harvested up to six times a year (registration of the variety is pending).

In addition to air conditioning control of humidity, temperature, and CO2 concentration, light intensity is important for stable indoor rice cultivation.

Mr. Hajime Miyazaki, the company’s managing director, explains.

Because of the height of rice plants, there were challenges in growing rice indoors, such as the need for space and the difficulty of adjusting light levels. President Shinichi Oku, a former professor at Osaka Prefecture University who was engaged in hydroponic research, and Dr. Murase, a Ph. D. in agriculture and a former professor at Osaka Prefecture University who was engaged in hydroponics research, Oku Shinichi began trial and error around 2005. The result was a new rice variety, “Mizu-no-Yume-Ina”.

While normal rice plants grow to a height of 90 cm to 1 m, Mizu-no-Yume Rice grows to only one-fifth of that height (15 to 20 cm). Also, while it normally takes three to four months to harvest rice, Mizu-no-Yume rice takes only two to two and a half months. This makes it possible to harvest up to six times a year.

As you can see from the photo, the rice is surprisingly small. This makes it possible to grow rice hydroponically in a multi-stage system in the same way as lettuce and other short vegetables, allowing high-density rice production even in a small space.

The LED system was jointly developed with the cooperation of Norihisa Otani of Fukuyama Soden Co. Otani, who spent several years developing LED wavelength control technology, describes the difficulties of hydroponic cultivation.

For hydroponic cultivation of rice, LEDs are indispensable to provide light as well as air conditioning throughout the year. However, the wavelengths of light used to grow grains require electricity, so it consumes two to three times more power than hydroponics for lettuce.

This makes the rice expensive on a profitable basis. The key to cost reduction lies in the technological innovation of LED chips produced by a limited number of manufacturers. This is an issue to be addressed in the future.

In addition to these cost issues, there are many things we need to work on, such as further stabilization of cultivation and establishment of a mass production system, but first of all, we want more people to know about the power of this Mizu-no-Yume rice. We hope to work in partnership with companies that are interested.

While hydroponic cultivation is envisioned in cargo containers and plastic greenhouses, the company is also considering large-scale hydroponic cultivation in a “grain factory” similar to a “plant factory” that grows vegetables.

If we can grow Mizu-no-Yume rice in such an environment, for example, it should be possible to further shorten the cultivation period, and there is still room for other improvements.

However, there are limits to what we can do on our own. If we can utilize ideas from companies with capital, I think the possibilities of Mizu-no-Yume Rice will expand even further.

The impetus was “rice cultivation in space”… We want to deliver containers that can grow rice overseas.

Why did President Oku start researching hydroponic cultivation of rice, which had been considered difficult? The late Dr. Jihiko Murase’s strong desire motivated President Oku.

Dr. Murase, whom I had known for a long time, had written many papers on hydroponics long before I met him, and in the 1910s, he was researching the possibility of growing rice in space. In the midst of his research, he found hope in rice cultivation in cargo containers.

He had lived abroad for a long time, and when he thought about the devastation of children starving to death in Africa, he thought of transporting a container overseas that could grow rice. That is when we started researching the hydroponic cultivation of rice in containers before space.

The company is proud of the great value of “Mizu-no-Yume-Ina,” which was developed out of a desire to help people in need.

Mizu-no-Yume Rice can be grown in areas where rice cultivation has been difficult, such as urban areas, deserts, and cold regions. Also, if the rice can be transported by container, it can be used to produce rice in countries that are still in conflict or in disaster-stricken areas in Japan.

However, as Mr. Otani mentioned, there are cost issues. Also, considering the rice shortage problem, the increase in abandoned farmland due to the aging of the population, and climate change, we felt that we should hurry to make practical use of this technology in a profitable manner. That is how we arrived at the multi-stage soil cultivation method, in which Mizu-no-Yume rice is grown in plastic greenhouses using natural light.

There is a lot of surplus land in mountainous areas. Even if a large-scale grain mill is impossible, plastic greenhouses can be built. Natural light can be used, and if we can go off-grid, we can expect further cost reductions. I think we can propose a new form of agriculture.

I am currently working on a project to grow rice for rice flour in plastic greenhouses on my farm in the mountainous areas of Hyogo Prefecture. The fact that we can grow rice without pesticides is one of our strengths, and we are thinking, for example, of using the rice harvested through this project to make rice-flour bread, which could then be included in school lunches.

It is said that one hectare of rice paddies can yield 500 kg of rice per year, but how much can be expected from soil cultivation in plastic greenhouses or hydroponics?

In soil cultivation using natural light, we are simulating two levels of shelves and three harvests per year, taking weather conditions into account, and expect to harvest about 1.5 tons per hectare.

If hydroponic cultivation is equipped with LEDs, it is possible to have three or four shelves and multiple harvests six times a year.

In hydroponics, rice can be grown as long as the LED lighting, temperature, CO2 concentration, and other conditions are met. Even if the area is small, such as a container, a small warehouse, or a room in a building, if the space is tall enough and meets the conditions, it can produce a considerable amount of rice,” says Miyazaki.

By the way, I am curious about the taste of rice. How does the taste of hydroponically grown rice differ from that of rice grown in rice paddies?

When cooked, it tastes much the same as regular rice, but when it cools down, it may have an impression similar to Thai rice. That said, it tastes better when stir-fried or steamed.

Onigiri, for example, is delicious because it is made with freshly cooked white rice, such as Koshihikari, which has a sticky consistency. In that sense, onigiri lovers may find it insufficient.

Of course, the product is still under development. Of course, the product is still in the development stage, but as improvements are made, there is a great possibility that the taste will become closer to the Japanese taste.

We have received many inquiries about Mizu-no-Yume Ina from overseas, including Persia and Spain, and we are receiving a lot of interest in the product. However, we would like more Japanese people to eat it if possible. When I look at the deserted and abandoned land in Japan, I feel that something must be done about it. I believe that the government should provide assistance for the future of agriculture, and I have been discussing this with municipalities. I would like to make this happen to please Dr. Murase, who passed away.

We are waiting in anticipation for Mizu-no-Yume Rice to make a difference in the future of Japanese agriculture.