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Plant Factory Sustainable agriculture beneficial for the environment, consumers and producers

Plant Factory
Sustainable agriculture beneficial for the environment, consumers and producers

※ Article updated on Mar. 2, 2022

  • Agriculture is facing various challenges, while supporting our lives. In addition to an aging workforce and a lack of successors, global warming and extreme weather events, including torrential rain, in recent years have boosted the necessity to achieve a sustainable agribusiness.
  • The plant factories the Mitsubishi Chemical Group (the MCG Group) operates are expected to solve those serious problems of agriculture.
Plant Factory image

A plant factory is a facility to stably produce crops without being affected by the weather by artificially creating the optimum conditions required to grow plants. In addition to contributing to stable food supply, the factories enable cultivation of farm crops in areas and environments unsuitable for agriculture. The factories also achieve the establishment of agribusiness that cares for the environment by reducing the use of water, nitrogen and other resources.

These features of plant factories are attracting attention as a method toward achieving the SDGs (Sustainable Development Goals), which aim to solve the food crisis and to step up measures for climate change.

Based on the light source used, plant factories are roughly categorized into the sunlight type and the fully artificial light type. We will describe step by step the factories the MCG Group is offering.

One of the Group’s factories is a sunlight-type hydroponics system for leafy vegetables. This cultivation system known as Napperland is a plant factory utilizing agricultural greenhouses. In the factory, various leafy vegetables, such as spinach, leaf lettuce and arugula, can be grown by hydroponics using a water and nutrient (liquid fertilizer) solution.

Napperland was developed with the aim of ensuring a steady supply of spinach in summer. In conventional open field cultivation, crop yields depend on the plant’s growing season. Spinach, for example, is in season in the colder months from November to February in Japan. In summer, the supply to the market declines due to difficulty with production outside Hokkaido and other cooler regions, resulting in high prices.

Nevertheless, demand for spinach exists throughout the year. That means enabling farmers to supply spinach stably when the price is high due to shortages can contribute to stabilizing farmers’ incomes. Napperland was developed aiming to improve farmers’ management under the concept that “To make it easy for anyone to produce quality vegetables that require advanced technologies for production.”

  • With Napperland, vegetables are grown in mildly sloped cultivation beds where a small amount of nutrient solution flows. In addition to enabling vegetables to absorb water and nutrients efficiently without waste, the system can reduce environmental impact as the volume of water required is only 3% of that required in open field cultivation.
  • By managing the growing media, where the nutrient solution is circulated, in small units, the system prevents disease outbreaks and pest breeding. As a result, the system has achieved supply of pesticide-free, safe vegetables. Moreover, the advantages of the system over fully artificial light type plant factories include less initial investment and lower operating costs due to the use of sunlight.
Cultivation bed of Napperland(cross section)

There are points, however, very critical for the production of quality vegetables other than the hydroponics system for leaf vegetables. That is because it is challenging to produce quality vegetables from poor-quality seedlings, and the productivity of crops highly depends on the quality of seedlings.

For farmers to grow high-quality seedlings, advanced technologies and labor-intensive operations are required. The solution to the problem is NAE Terrace, a system to produce seedlings using artificial light in a facility. The system has achieved stabilizing quality and yield of seedlings by automating temperature control, light irradiation, irrigation and other operations.

The MCG Group has established plant factories that can annually mass-produce quality crops in a planned manner without being affected by the weather by combining the artificial light type NAE Terrace and a sunlight type hydroponics system such as Napperland. The automatic management of the growing environment for crops, such as temperature and air conditioning, by computer control has enabled anyone to grow vegetables easily without difficult technologies.

The system has been introduced not only in Japan but in China and other countries.

And now, plant factories are evolving further. The prime example is a next-generation, fully artificial light type plant factory developed for producing vegetables for processing use and commercial use.

The background to the development of the plant involves growth in the demand for home-meal replacements and eating out due to an aging population with low birthrate and an increasing number of single-person households. As a result of the increase in the number of people who do not make meals at home, 60% of the total demand for vegetables has been for processing use and commercial use in recent year in Japan. To meet this growing demand is considered as another key to stabilize farmers’ management.

Production of vegetables for processing use and commercial use are thoroughly required to meet the four Fs: fixed time, fixed quantity, fixed quality and fixed price. To satisfy the criteria, measures for a crop failure caused by natural disasters almost every year are required as such failure is a huge problem for farmers.

In response, the MCG Group embarked on developing a fully artificial light type plant factory, which has been difficult to operate widely due to its high cost. Leveraging the expertise on hydroponics it has accumulated, the Group developed AN (Agriculture Next), a practical new artificial light hydroponics system.

The system has cut down the construction costs of the facility by using agricultural greenhouses as is the case in sunlight type plant factories. By installing high-strength LED lights as the light source, the system ensures a cultivation environment where vegetables can grow without any inhibitions while reducing power consumption.

As a certain level of quality is required for vegetables for processing use and commercial use, in the case of open field vegetables, only 60-70% of vegetables on average are used as raw materials for fresh-cut vegetables because of excluding the portion damaged by insects etc. If a torrential downpour occurs, the supply of vegetables will not be able to keep up with the demand and prices will soar. At the newly developed plant factory, the system has ensured a stable supply, achieving quality so high that almost all of the vegetables can be used for the products (a yield rate of 90% or more).

For ensuring the high quality of vegetables, a newly developed air-conditioning system to send wind effectively to the growth point of vegetables has been installed in a new artificial light hydroponics system. The system prevents tip burn (bruises caused by a lack of nutrients) that degrades product quality.

In addition, an automatic spacing function is installed to extend the space between vegetables as they grow. The automated and unmanned cultivation area drastically increased operating efficiency and hygiene. The factory can be operated by a third of the staff required in conventional plant factories and minimizes the risk of contamination by foreign substances, including pests.

The new plant factory, AN with such advantages has achieved a production cost of vegetables 50% less than that at the Group’s conventional fully artificial light type plant factory. The vegetables are better in quality, and the yield amount per plant three or more times that at conventional factories was recorded in the comparison of leaf lettuces. In addition to being efficient, the new factory can grow fresh and tasty vegetables.

The MCG Group has just begun to promote new plant factory to the market. The Group is aiming at full-scale promotion of the factory by establishing a system to further lower production costs.

The word “factory” may give an artificial and inorganic impression to those who first learned the term “plant factory” from this article. The MCG Group, however, aims to develop a plant factory system of Sampo-yoshi, meaning “three-way satisfaction” in Japanese.

Reduction in environmental impacts contributes to the achievement of sustainability. Pesticide-free cultivation contributes to peoples’ health. And stable earnings improve the business conditions of farmers and allow the manpower shortage to be addressed. The global environment, consumers and producers all benefit. The MCG Group expects that its plant factories will bring such an ideal future, and this is what the achievement of sustainable agriculture means.

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