April 14, 2023
BEIJING – Innovative approach brings rewarding yields, saves water
One year ago, Li Xinxu was an official responsible for promoting technology at a government department in Beijing. However, he was not happy with his day-to-day work and longed for a more meaningful occupation.
Now, the 39-year-old operates new-tech farming in a 100,000-square-meter greenhouse in a northwestern suburb of the Chinese capital.
Cherry tomatoes hang up to 4 meters high, ripening on tiered shelves in the greenhouse, where the temperature is maintained between 15 C and 30 C in all seasons. Worker bees occasionally emerge from hives in the structure.
Fruits and vegetables are nourished in liquid nutrient solutions, rather than being grown in soil, thanks to vertical farming. This cutting-edge agricultural technique was developed by scientists to overcome the lack of resources, particularly as the world’s population continues to rise.
The United Nations Food and Agriculture Organization has said the global cropland area per capita decreased from about 0.45 hectares in 1961 to 0.21 hectares in 2016. The UN also reported that the world’s population reached 8 billion in November, and is expected to stand at 9 billion by 2037.
Against this backdrop, vertical farming is seen as a solution to maximize yield over a limited area by optimizing resources and space.
As urbanization accelerates in China, agricultural experts and leaders of “new farming” companies are exploring ways to localize this agricultural technology to ensure that people living in cities have access to stable food supplies.
In January, National Bureau of Statistics figures showed that China’s urban population exceeded 920 million by the end of last year, and will continue to rise.
Since 1999, the vertical farming technique proposed by a university professor in the United States has been adopted not only in Beijing, but in different parts of the world.
Li Xinxu, now CEO of Beijing Cuihu Agricultural Technology Co, learned about vertical farming during three months of agricultural training in the Netherlands in 2014.
He said he was initially intrigued by the way this agricultural technique prevented insect disease.
“Before I went for training in the Netherlands, I visited croplands from time to time in Beijing’s Changping and Miyun districts from 2011 to 2013. The farmers were plagued by insect diseases and were finding it hard to reduce water usage while spreading manure on their plants,” Li said.
He added that he was determined to find an economical and environmentally friendly agricultural method that saved water.
Vertical farming in the Netherlands gave him ideas. Some 9,700 hectares of crops are grown in Dutch greenhouses, which use less fertilizer and water than those elsewhere. A farm in the Netherlands only uses 2.25 liters of water to grow about half a kilogram of tomatoes, while on average, more than 126 liters of water is used for such a purpose elsewhere.
After returning to China, Li decided to put the innovative technology to use in greenhouses owned by local farmers. As a result, more than 1,200 hectares of farmland in Beijing have benefited from this approach.
Vertical farming, first advocated by Dickson Despommier, a professor of microbiology at Columbia University in the US, involves growing local fresh produce in high-rise towers made from glass and steel. Despommier believes that by 2050, about 80 percent of the global population — which by then is expected to reach 9.7 billion — will live in cities.
He envisioned a 30-story skyscraper able to provide food for 50,000 residents in downtown Manhattan, New York, with about 160 such buildings providing food supplies for all the city’s residents throughout the year.
He said abandoned garages and factories are ideal sites for vertical farming, with some farms in the US already producing vegetables in indoor or rooftop spaces.
Singapore, which is densely populated and imports more than 90 percent of its food, has taken to vertical agriculture, with more than a dozen rooftop farms springing up across the city-state.
Jack Ng, founder and CEO of Sky Greens, the largest and first vertical farm in Singapore, said: “During the COVID-19 pandemic, infected areas were locked down, but what about the food supply? People need food, and they should have a stable supply channel.
“If our agricultural produce is grown not just in the fields but also in the city, the cost of transporting the crops will be reduced.”
Ng’s vertical farm in the Lim Chu Kang area of Singapore produces about 1 metric ton of vegetables a day, 10 times more than a traditional farm. Some 2,500 lettuces or Chinese cabbages are grown in 9-meter-high A-shaped towers in each protected 5.5-sq-m indoor greenhouse. Only 12 liters of water are needed to irrigate 1 kilogram of the vegetables, a saving of 95 percent compared with the amount required for field planting.
A new micro farm developed by Ng combines vertical farming with tanks for fish and prawns in a space the size of a basketball court, giving urban residents access to various kinds of food.
Once the vegetables grown at Ng’s vertical farm are ready to eat, they are delivered directly within hours to supermarkets in downtown Singapore.
“We have limited land but infinite space. Abundant sunshine all year round in Singapore provides natural nutrients for the plants. Our farm generally does not require the use of artificial lighting,” Ng said.
Such lighting plays a big role in the growth of green plants in places where there is insufficient sunshine. Artificial lighting can better promote crop growth by making the plants more productive, while saving a significant amount of energy.
Yang Qichang, deputy director of the Chinese Academy of Agricultural Sciences’ Institute of Urban Agriculture, said that artificial lighting enables crops to be produced throughout the year, adding that the growing environment is fully controlled.
These conditions ensure the stability of crop yield to the fullest extent, Yang added.
“Vertical farming enables plants to be grown in nutrient-rich water, with the light they require supplemented by artificial sources. Some resources that are considered useless in the city can be used in vertical farming, such as sewage and carbon dioxide in the air,” Yang said.
Fruit and vegetables grown indoors can resist insects and soil-borne plant diseases, as they are grown hydroponically (in sand, gravel, or liquid, with added nutrients but without soil). This method prompted Li to launch his vertical farm in northwest Beijing.
The farm’s first growing season started in September. “In our first season, I expect to achieve an output value of 40 million to 50 million yuan ($5.8 million to $7.3 million) by July, and we are aiming for a turnover of 80 to 100 million yuan by 2025,” Li said.
He added that 40 kg of tomatoes can be produced per sq m at his farm, with some cherry tomato varieties yielding 50 kg per sq m.
Yang said that in China, about 250 plant factories use vertical farming.
Beijing AgriGarden Protected Horticulture Technology Co, which was established in 2002, is one of the first such companies in the country to use vertical farming. Located at the National Agricultural Science and Technology Innovation Park in the Zhongguancun area, the company boasts seedling laboratories, vertical farming planting areas, ecological meeting rooms, and garden offices.
A workshop at the park, which grows cucumbers on an area of more than 1,000 sq m, achieves a yield of over 200 kg. Four varieties of cherry tomatoes produce an annual yield of 20 kg per sq m, while strawberries planted at the farm boast a far superior yield to traditional planting methods.
In a glass greenhouse, a robotic arm carries vegetable seedlings individually to a 19-tier rack with LED lighting at a height of 13.5 meters. Over 28 days, the seedlings are grown in nutrient solutions on the racks until they ripen.
Wei Lingling, CEO of Beijing AgriGarden Co, said: “Harvesting of a single crop can only be achieved once or twice a year in field planting. But in our greenhouse lab, we can harvest crops 12 times a year, as the vegetables ripen every 28 to 30 days.”
Although large-scale commercial vertical farming is still not well established in China, real estate companies, local governments, schools and libraries nationwide have collaborated with Wei’s company in more than 100 projects to practice vertical farming.
“When British entrepreneurs and agricultural experts visited Beijing (in 2018), they wanted to export their vertical farming technique to us. But they were surprised to find our intelligent farm program, and after attending a seminar, they decided to work with us,” Wei said.
She envisions establishing small vertical farms in subway stations, so that when commuters finish work, they can choose vegetables and take them home directly, rather than buying those transported from markets several hundred kilometers away.
“In this way, logistics costs will be saved, and residents can obtain really fresh vegetables,” Wei said.
Vertical farming seeks to answer the question of why can’t cities produce food as well as consume it.
The output and profits from agricultural produce grown at plant factories can be astonishing.
However, Wei said it is still challenging for vertical farming to go commercial on a large scale unless there is a real need, as the cost of launching and running each farm is extremely high.
“The initial cost per square meter of setting up a vertical farm is about 2,000 to 3,000 yuan, but operating expenses can be relatively high. For example, the LED lights and air conditioning control systems are expensive,” Wei said.
She added that crops suitable for vertical farming are limited to dwarf vegetables, fruit, herbs, edible mushrooms, as well as flowers.
“We’re working to grow crops such as rice and wheat, but there are few business opportunities for them, as they require a lot of light, which demands a significant amount of energy and is costly,” Wei said.
Yang, from the Chinese Academy of Agricultural Sciences, said it is impractical to completely replace greenhouses and field planting with vertical farming systems, but such farms can supplement and innovate modern agriculture.
Obtaining land to build vertical farms is particularly costly, in large cities such as Beijing and Shanghai.
Data from the Beijing Municipal Commission of Planning and Natural Resources show the price of land per sq m near the Taiyanggong area in the city’s Chaoyang district reached more than 240,000 yuan at the end of May.
In addition, it costs tens of millions of yuan to construct a vertical farm building, Yang said.
Beijing residents have shown an interest in the latest agricultural technology. Outside Beijing AgriGarden Co, a small shop sells fresh organic vegetables and fruit grown by the company.
Guang Hua, 70, cycled to the store from her community in Haidian district. She noticed the hydroponically — grown lettuce on sale and asked the shop assistant if it could be sold with the bag containing the nutrient solution. The assistant told her the bag could be bought, for an additional payment.
“I want to buy the lettuce and cook it at home. If the store provides me with the option of growing the lettuce in my apartment, why wouldn’t I choose that?” Guang said.