19 October 2019

Zero Hunger Series: Feeding 10 billion people using air, nutrients and water

World Food Day, celebrated every year on 16 October, marks the founding of the Food and Agriculture Organization (FAO) of the United Nations in 1945 as an organization that deals with global food and agricultural issues. The number of people going hungry has increased since 2014 and the prevalence of undernourishment has remained virtually unchanged in the past 3 years. This reversal in progress sends a clear warning that more must be done urgently if the Sustainable Development Goal of Zero Hunger is to be achieved by 2030. 

A profound change of the global food and agricultural system is needed to nourish today's 800 million hungry and the additional 2 billion increase in global population expected by 2030. The University of Pretoria (South Africa), United Nations Academic Impact (UNAI) SDG Hub for Goal 2: End hunger, achieve food security and improved nutrition and promote sustainable agriculture, recognizes the importance of research and innovation in food and agriculture in contributing to this movement of change. In celebration of the 2019 World Food Day, UNAI is collaborating with the university on a series of articles focusing on food security in Africa. In this last article, the University of Pretoria introduces the benefits and boundless possibilities of aeroponics in promoting food sustainability.

By the year 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 the Impilo projects to research the aeroponics and its potential contributions to end hunger and malnutrition. While there is still much to be investigated in terms of the potential challenges, such as 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 meter and is approximately one and a half meters tall. A modest commercial unit suitable for domestic entrepreneurs covers a mere 25 square meters 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. 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," said 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 open 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.

By Professor Nigel Barker, Head of the University of Pretoria’s Department of Plant and Soil Sciences, and Elizabeth Mkandawire, PhD, Postdoctoral Fellow and Coordinator: UN Academic Impact Hub for SDG2 at the University of Pretoria’s Institute for Food, Nutrition and Well-being.

Other articles in the series: