Beating hunger: How aeroponics could provide the solution to feeding 10 billion people

By 2050, we will need to produce at least 50% more food than we do currently to feed 10 billion people. However, over half the land in the world is already used to produce food, and agriculture has a significant negative impact on the environment. Innovations are needed to produce enough food sustainably without using more land. Aeroponics is an innovation that grows plants in the air with no soil and little water.

The University of Pretoria’s Department of Plant and Soil Sciences has signed an MOU with Impilo Projects to research aeroponics and its potential contribution to ending hunger and malnutrition. While there is still much to be investigated in terms of the potential challenges (for example, how to manage pest outbreaks), the benefits of such technologies are indisputable. Currently in the trial phase, the research team is exploring the pros and cons of these soilless plant production systems.

The Impilo aeroponic unit

The Impilo aeroponic unit is a standalone structure that supports vertical farming and can be used by residential as well as commercial farmers. The largest aeroponic unit can hold up to 96 individual plants while the smaller unit, mainly for household use, holds 16 plants. The unit stands on about 1 square metre and is approximately one and a half metres tall. A modest commercial unit suitable for domestic entrepreneurs covers a mere 25 square metres and can contain over 1500 plants at any one time.  

Such a unit is powered by less electricity than a kettle, and can be adapted to solar power. Water consumption is drastically reduced when compared to “conventional” agriculture, and (depending on the crop) each vertical unit can use as little as 20-25 litres of water a week.

The known potential and benefits

The research team has experimented with different types of crops, including kale, spinach, herbs and flowers. They are currently exploring the potential of the unit to grow both mainstream crops as well as indigenous African vegetables. However, limitations exist on the types of crops that can be produced; for example, carrots as a root crop cannot be grown in these units. Nonetheless, such technologies can ensure that a diverse range of food is available all year.

In a country where healthy diets are becoming more expensive, these units allow even urban dwellers living in small apartment buildings to grow their vegetables and possibly fruit like strawberries. Furthermore, gardening in itself is therapeutic, but people with disabilities may struggle to participate in conventional gardening activities. These vertical units can be managed by anybody, allowing the disabled and those in wheelchairs an opportunity to explore the pleasure of growing and nurturing plants.

“These units allow people to develop a new and different relationship with plants. They have a societal impact on how people view and grow food,” says Prof Nigel Barker, Head of the Department of Plant and Soil Sciences.

Boundless possibilities

The possibilities of this technology are boundless, with opportunities to explore a range of aspects of plant and human nutrition. It is also hoped that this facility will be used to determine how to increase the nutrient and essential mineral content of the vegetables grown aeroponically. These vegetables can thus offer solutions to persistent African challenges of micronutrient deficiencies such as iron deficiency anaemia.

These units also provide opportunities to research the cultivation and propagation of medicinally important and rare plants for conservation. The Impilo aeroponic units can reduce soil degradation, infertility and improve malnutrition. The implications for food security of farmers who often work on less than 2 hectares of land are limitless. The acquisition of this aeroponics research facility has thus opened avenues for a diverse range of experiments that are on the Department’s research agenda.

The concept of growing food is evolving. Such innovations inspire hope that it will be possible to feed future generations.

Dr Elizabeth Mkandawire, PhD, is a Postdoctoral Fellow and Coordinator: UN Academic Impact Hub for SDG2 at the University of Pretoria’s Institute for Food, Nutrition and Well-being.

Professor Nigel Barker & Dr Elizabeth Mkandawire

October 16, 2019

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Researchers
  • Professor Nigel Barker
    Professor Nigel Barker is Head of the Department of Plant and Soil Sciences in the Faculty of Natural and Agricultural Sciences (NAS) at the University of Pretoria (UP). He joined the University six years ago, after he had been at Rhodes University for 18 years. He completed his undergraduate studies and MSc at the University of the Witwatersrand and his PhD at the University of Cape Town (UCT).
    Prof Barker’s area of training was plant taxonomy and systematics, with a specialisation in grass taxonomy; he holds an MSc and PhD in this area. “Over the course of my career, I have expanded my interests, and have worked on the systematics of other plant families including daisies, proteas and legumes,” he says.

    He is a molecular systematist who uses DNA data to resolve evolutionary relationships in plants and animals. “I then use the data to understand the biogeographic patterns and the historical processes that resulted in the distribution patterns we see today,” Prof Barker explains. “I also use DNA data in population level studies on genetic diversity and phylogeography [the geographic ordination of genotypes] of plants and animals.”
    Prof Barker adds that he does research as and when he can. “UP has amazing research facilities, and I have started projects with a wide range of collaborators across the faculty. I have been able to undertake new research direction as a consequence of this.”

    He is interested in researching and promoting the cultivation and widespread use of African “orphan” crops. These are crops that are not traded internationally, but rather grown and eaten as part of local diets. Relating to this interest, Prof Barker is the UP representative on the ARUA Centre of Excellence in Sustainable Food Systems’ Implementation Committee for Orphan Crops.

    Prof Barker also has an interest in mountain biodiversity and ecosystems, particularly on the Great Escarpment (over 15 publications) area and, more recently, the Waterberg mountains in Limpopo. He is the lead investigator on a R4,5 million project to document the biodiversity of these mountains. The project includes researchers from seven universities, a few museums, the South African National Biodiversity Institute (SANBI), the South African Institute for Aquatic Biodiversity (SAIAB) and South African National Parks (SANParks), as well as several local landowners and stakeholders in the region. Prof Barker regards the project as a recent highlight as it has been two years in the planning but was only funded and effectively initiated in 2021.

    “My field of research contributes to the betterment of the world because if we are to address just about the whole gamut of Sustainable Development Goals, it is essential to understand life on earth – where it is found, how it evolved, what genes and genomes it possesses, and so forth.”
    Apart from colleagues in his own department, Prof Barker collaborates with the Departments of Zoology and Entomology, Biochemistry, Genetics and Microbiology, and Agricultural Economics, all within the NAS faculty. “I also have an interest in community engagement activities, and am collaborating with the Arts Department in the Faculty of Humanities around the role of art in promoting awareness about plants. As part of this, he and a colleague, Dr Angelique Kritzinger, are supervising a collaboration between plant science and art students for a community engagement module.”
    As to who inspired him in his research, Prof Barker says his PhD supervisor, Prof Peter Linder, who lectured at UCT and at the University of Zurich and is now retired, was a huge inspiration and is his academic role model. “He is a globally recognised expert in African flora, and known for his love of plants, Africa and its people; his joie de vivre is amazing.”
    Prof Barker hopes to positively impact “the lives of ordinary folk eking out a living on African soil”. “No number of scientific papers in fancy journals can equate to that. I have not fully got there yet – maybe my interests in the Waterberg biodiversity and conservation, or orphan crop work, will be a start,” he says.
    “We need to ensure that we leave some part of planet Earth not only better understood but also untouched, or at least protected from the stupidity and greed of Homo sapiens – the supposed ‘wise’ man. We need to use Earth’s resources more effectively by using local plants for food and other applications, such as sources of medicines. That is why my research matters.”
    Prof Barker’s advice to young people interested in his research area is to get out into the field and learn to love, identify and understand the ecosystems that surround them. Even urban systems have a form of ecology, he says. “You don’t have to go to the Kruger Park to do this – your backyard or park is enough. Join organisations or clubs that can help you to learn and grow, such as the Botanical Society of South Africa, or a birding club. Download and contribute to apps like iNaturalist, which document our planet’s biodiversity, and make your own contribution to this effort too.”
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