Aeroponics; feeding
tomorrow's world ?
If our world is to survive for much longer, we have
no choice but to reduce the use of natural
resources and cut out wastage. Compared to
traditional agriculture, aeroponics does both.
The world's population is expected to continue growing until the end of
the twenty-first century; that at least was the general consensus of
experts until 2019. Maybe in the new post-Covid reality, the rate of
growth will slow; but even so, unless Covid-19 or some other new virus
causes millions more deaths than initially predicted, the world's
population will continue to grow, putting ever-increasing pressure on the
natural environment, on resources, on living space, and most critically on
food and water. Aeroponics will be part of the solution.
According to a United Nations FAO report published in 2011, almost half of
the fruit and vegetables produced in the world go to waste – they never get
consumed by the humans for whom they are grown.
Wastage occurs throughout the production and distribution cycle, during
production, during transformation, during transport, and even – notably in
developed economies – after purchase by the final customer.
Fifty percent of all fruit and vegetables going to waste, that is an enormous
amount of wastage, and not just in economic terms. This wastage has a huge
impact in terms of natural resources, particularly space and water, which in
turn have huge implications for the global environment.
Cutting out all waste in the production and distribution of food is an
impossible goal. Even people living in small eco-sustainable communities
generate waste. Even in organic crop production, pests and disease cause
wastage; and even if harvested and distributed locally, part of a crop will
always be wasted.
But there is a large difference between wasting fifty percent of all fruit and
vegetables produced worldwide, and the unreachable goal of achieving no
waste at all. Between 50% and zero, there is plenty of scope for significantly
reducing the volume of food waste worldwide simply through the use of new
more efficient production methods.
Studies have shown that packaging and distribution systems account for
about 25% of total wastage of fresh fruit and vegetables, leaving plenty of
opportunity for improvement. In an ideal world, and as in the past, much of the
food consumed in cities would be produced locally, not shipped thousands of
miles as happens today.
In 1998, the US Department of Agriculture released a study into fruit and
vegetables arriving at the Chicago Terminal Market, the main point of
distribution for the American Middle West. The report showed that basic
vegetables including lettuce, broccoli, peas or cauliflowers all traveled over
2000 miles (over 3000 km) before reaching the market... and before being
shipped on to supermarkets across the region. Yet Chicago is in the heart of a
massive agricultural area. Granted it can get pretty cold in winter,
but with modern agricultural techniques, the Midwest could be self-
sufficient for many types of fruit and vegetables, cutting out the massive
environmental cost of shipping tons of vegetables half way across a continent.
Since 2011, Chicago's O'Hare airport has been home to an aeroponic garden
(photo top of page) , where people can see how vegetables can be grown in an
environment that is not only without soil but even without any
permanent medium in which to grow. In this experimental garden, plants are
grown, as the name suggests, ... in the air, their roots hanging down in nothing.
Hydroponics, growing plants in troughs of nutrient-rich water, has been
developing since the 1970's. Aeroponics takes things one step further, by
removing the water and replacing it with air. Not just air, obviously; while plants
are grown with roots hanging in the air, these roots are regularly sprayed with a
nutrient-rich solution that gives them just what they need for optimum growth.
It's very high-tech, it's not cheap, and it's a long way from currently popular
organic farming techniques. Yet in many ways, aeroponics is actually more
environment-friendly than even the most strictly managed traditional organic
farming methods. And it's down to one factor: waste.
Traditional farming is wasteful; modern intensive agriculture relies on large
inputs of external resources, notably heat, water and nutrients. The vast
amounts of water used by agriculture are already causing serious problems in
many parts of the world; beneath California's San Joaquim Valley, the world's
most productive agricultural area, water tables have been dropping for almost a
century, and scientists estimate that the land... not the water table below it...
has sunk by over 8 metres in some parts. NASA calculate that Southern
California had a "water deficit" of 4.2 gigatons per year from 2002 to 2015.
Aeroponic agriculture reduces water waste to zero. The only water used is
what is actually taken up by the roots of plants when they are sprayed. Any
water not used can be collected and reused.
The same goes for nutrients; in traditional agriculture, plants only extract a
small proportion of nutrients from the ground, and good ground will have many
nutrients in it that will not be used at all by the crops grown on it. In an age of
diminishing natural resources, traditional agriculture uses millions of tons of
chemical fertilizer each year, much of which goes to waste. In Brittany, France,
many streams and beaches have been seriously polluted by nutrient-rich water
running off fields, causing "algal bloom" along the seashore and covering some
beaches in green slime. With aeroponic agriculture, no nutrients are lost, so
there is no risk of unintended pollution.
One big advantage of traditional agriculture is that it almost always uses
natural heat and light, even if under glass or plastic. Aeroponic agriculture, by
contrast, may require artificial heat and light, specially if practised indoors. But
with the development of small-scale locally-sited renewable energy production,
and highly energy-efficient buildings and lighting systems, large-scale indoor
aeroponic vegetable growing units are liable to be a feature of tomorrow's
cities.
If all the lettuces consumed in Chicago in winter could be grown locally, in
carbon-neutral zero-waste aeroponic "farms", instead of being brought in by
truck from California, that in itself would lead to a huge reduction in the use of
water, minerals, land-space and transportation costs. Reproduced on a global
scale, reduced use of natural resources will be vital for ensuring a sustainable
future for generations to come, even when the global population goes above 10
billion.
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