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Hydroponics: a smart way to stablise food supply
Food of the future
We have enjoyed the convenience brought by the globalisation of food and grain. Almost all of Hong Kong's foods are imported. More than half of its rice is from Thailand, while Vietnam supplies 25 percent. As for pork, since the outbreak of African Swine Fever last year, Hong Kong has imported more frozen meat from Brazil, Thailand, Spain, the Netherlands, the United States, and France, instead of live pigs from the mainland.
However, the recent epidemic has caused us to reflect on the issue of food supply which many places have actually gotten themselves prepared for.
With global warming and rising water levels, coupled with typhoons and rainstorms, Bangkok, a city located in a low-lying swamp area, is particularly vulnerable to climate impacts. The built up of the urban environment further aggravates the situation by reducing water seepage through natural soil. By 2030, 40 percent of the land in Bangkok will be submerged by floods every year, according to the World Bank estimate.
Bangkok has been very proactive with taking preventative measures for future disasters. In December last year, the largest rooftop farm in Asia was officially open at Thammasat University, just 40km from the city centre. The 22,000 square metre (236,806 sq. ft.) green roof tackles climate impacts by an all-in-one solution: incorporating modern landscape architecture with traditional agricultural ingenuity, the green roof, urban farming, solar roof and green public space. 7,000 square metres (32 percent) of its land is for farming. It is estimated that 3,745kg of rice will be harvested every year, which can supply 135,000 meals.
However, in a crowded urban environment like Hong Kong where land is a scarce resource, traditional farming models of cultivation in soil may not be economically viable. Therefore, hydroponics offers an attractive alternative.
The power of hydroponics
The NASA of the United States studying hydroponics for more than 10 years refers to it as "farming for the future" due to its high efficiency.
A private enterprise in Taiwan displayed a 28,000 square foot (0.26 hectares) smart farm a few years ago with 14 vertical-growing waterways. It planned to expand and cultivate more than 100 types of crops, with an expected harvest of 16,000 tons, equivalent to the harvest of 10 hectares of land of which the land use efficiency could reach almost 40 times that of the traditional one. At the same time, a high tech Japanese urban farm was also reported to have reduced the growth cycle of lettuce from the conventional two months to 40 days by vertical hydroponics. And according to a study by Arizona State University (ASU), the harvest of hydroponics, lettuce cultivation for example, can cultivate 11 times more than that of traditional methods in the same allotment of space.
Another beauty of hydroponics is that the water consumption is far lower – only one tenth of cultivation in soil. Water consumption is a key consideration as fresh water is becoming more and more precious. According to the Food and Agriculture Organization of the United Nations (FAO), traditional agriculture consumes 70 percent of the world’s fresh water. The US Department of Agriculture also mentioned that irrigation water in many western states accounted for more than 90 percent of the total water consumption in that area.
Therefore, it is imperative to develop alternative farming methods before water scarcity becomes a threat to our survival.
In addition, hydroponics can be controlled in all weather conditions, including nutrients delivered to plants, without disruption by storms and rainfalls. At the same time, there is no need for weeding and less pesticides are used, saving significant costs.
A pricey alternative
The issue of cost, however, is a down side of hydroponics.
This includes the use of high technology which consumes far more electricity than traditional methods – nearly as much as 82 times in the lettuce experiment, according to the same report by ASU.
Furthermore, the equipment is expensive and not easily accessible. This difficulty encountered by a Malaysian engineer who wanted to try hydroponics on his own balcony was typical: all relevant tools and materials had to be imported from other places such as China, Japan, Singapore, and Taiwan.
Even professional farmers face the same problem. The Nikkei Asian Review quoted the Japan Greenhouse Horticulture Association that 60 percent of the companies failed to make a profit.
Having said that, under climate change and unexpected global issues like the current COVID-19 pandemic, ensuring a stable food supply is becoming an important strategy. Therefore, many Japanese companies, Panasonic for example, have set up vegetable factories in Singapore to supply vegetables to local Japanese restaurants; while in Moscow, a Japanese company has built a factory to produce strawberries and tomatoes at the end of last year.
Although hydroponics currently consumes a lot of energy, this cultivation method has great prospects when energy-saving methods are eventually found. To be a sustainable smart city, it is time for us to think about how to secure our food supply chain and improve the city's resilience.
Dr. Winnie Tang
Adjunct Professor, Department of Computer Science, Faculty of Engineering and Faculty of Architecture, The University of Hong Kong