january-2019

40 / TREND / Vertical farming
TREND / 41
CLIMATE-SMART FARMING
Ogbole has devoted his time and resources to building modern
farms that explore the latest technologies for agriculture, which
may address some of the greatest problems the world is facing
today. He’s producing more crops in less space, while minimising
environmental damage. Innovative technologies, such as aeroponics,
hydroponics and aquaponics enable farmers to grow
crops in vertical stacks without soil. This sounds high-tech, yet
the basics are simple. “The function of soil is to act as support,
retain water and allow for aeration,” says Ogbole. “If we can use
alternative materials in this function, we can grow crops without
soil. Try it at home: if you keep some vegetables inside a few
bowls of water and leave them for three to seven days, the roots
will come out. Add fertiliser to the water and you will be carrying
out hydroponics.”
HOW IT’S DONE
Hydroponic farmers grow vegetables in stagnant water
(needing aeration via air stones) or flowing water. A liquid nutrient
solution is added as a growing medium, while essential
minerals sustain plant growth. Aquaponics pioneers are taking
it a step further by combining the cultivation of plants and fish
into one ecosystem, which is comparable to a fish tank with a
garden on top. The waste – urea or ammonia – produced by the
fish is the foundational nutrient for leafy vegetables, so it’s used to
feed them. The circular system allows for the growth of vegetables
without regular water replacement, as the plants recycle the water
by cleaning it.
Aeroponics is sometimes considered to be a type of hydroponics
because water is used to transmit nutrients, but the system
is different because it grows plants in the air without the use of
“Hydroponics and aquaponics
enable farmers to grow crops in
vertical stacks without soil”
soil or an aggregate medium. The roots hang suspended in the
air, while the nutrient solution is sprayed onto them in the form
of a fine mist.
Choosing the best soil-free system depends on the type of
crops and space available. For tuber crops, such as potatoes and
yams, aeroponics gives the best results because it provides easy
access to the root (tuber) region. The YIIFSWA-II project, led
by the Beninese agricultural engineer Dr Norbert Maroya, pairs
scientists from the International Institute for Tropical Agriculture
with farmers. They are collaborating in order to establish a seed
system that ensures that high-quality seed tubers – of various yam
varieties – are readily available to smallholder farmers. “Seed
tubers are the most crucial elements in the livelihood of yamgrowing
communities, such as Nigeria and Ghana, and food
supply is heavily dependent on the seed security,” says Maroya.
“Although farmers save about 30 percent of their yield with seed
tubers, the majority is ridden with pests and diseases that have
Getty Images
accumulated in the tubers and soils.” Maroya and his team are
using aeroponics to facilitate a rapid and safe multiplication
of yam seed tubers. Their objective is to achieve a 30 percent
increase in the productivity of yam cultivation for at least
320,000 farmers in Ghana and Nigeria.
MORE CROPS, LESS IMPACT
“The hydroponic system supports the growing of all leafy
vegetables, herbs, fruits and starchy foods,” says Peter Chege,
entrepreneur and founder of Hydroponics Africa. Hydroponics
and aquaponics are often considered a cost-intensive enterprise,
but Chege is convinced that it doesn’t need to be. Over the
years, the Kenyan entrepreneur has learned that many farmers
incur high costs for animal feed even though the quality is often
unsatisfactory. To address this problem, he and his team started
developing hydroponic systems that enable farmers to grow
animal feed at low cost, while also providing them with the
means to grow vegetables.
Evidently proud, Chege says, “Since 2015, we have been
rolling out our simplified hydroponic systems, which are not
only practical, but cost-effective too. We’ve developed an optimal
nutrient solution specific to various crops, which directly irrigates
the crop’s root through the watering system. This minimises wastage
of both nutrients and water (excess water is being recycled).
For the substrates, we use recycled materials, such as pumice,
wood chips, mattress tissues and even plastic cups. The water
system is fully automated and powered by integrated solar panels,
and there is zero use of herbicides. As there is no competition
for nutrients, the crops are highly nutritious compared to crops
grown under conventional methods, and they mature 30 percent
faster, resulting in more harvests per year.”
EMERGING POTENTIAL
The impact these new farming methods have on production
is significant. “If you want to grow tomatoes in the soil, it will
take you three months; with a hydroponic system it takes you,
at most, a month. Growing wheatgrass in the soil takes three to
four months, with this system it takes only seven days; without
any pesticides, very little fertiliser and no soil,” says Ogbole in
his TEDx Talk.
Will these vertical, soil-free farms unleash a “green revolution”
in Africa, as proponents love to call it? With just three major
suppliers, hydroponics is still an emerging industry, but according
to Chege, business is booming. So far Hypdroponics Africa has
installed more than 5,000 hydroponic systems in Kenya, Uganda,
Rwanda and Somalia, and the company has extended its presence
in Burkina Faso and Nepal. Based on the current high demand,
they expect an exponential growth of 70 percent in the next few
years.
Soil-free farming systems are inseparable from the global
movement that seeks to make agriculture climate-smart and
future-proof. Most governments now recognise the need to
develop interventions, and some have already taken action.
As one of the first in Sub-Saharan Africa, Kenya launched
the Climate Smart Agriculture Strategy 2017–2026, in which
the government declares its objective to make agriculture more
sustainable and resilient through collaborations and education.
“The major challenge is knowledge,” says Ogbole. “By
training people and making them aware of the potential of
vertical and soil-free farming, agriculture becomes a tool to
build the nation we so much desire. I’m not saying we should
eliminate soil, but I do believe we should complement soil.
Vertical, soilless farming is one of the ways to ensure the
future of food.”
30
Urban aeroponics gardens can grow in half
the time it takes for them to grow in soil,
with a yield of 30% more.
90
Aeroponic farming requires around 90%
less water than soil-grown crops.
6,400
The biggest aeroponics farm in the world
is being built in Newark, US, with 6,400 sq
m of cultivated spaces without soil.
8,000
By using aeroponics, a farmer can produce
up to 8,000 lettuce plants in a 3 m x 1 m
space each year.
50,000
A yam tuber that is multiplied using
aeroponics can get more than 50,000
tubers annually.
Peter Chege
Sources: Environmental Assessment Agency PBL, International Institute for Tropical Agriculture (IITA), YIIFSWA-II project, IITA University of Chile 2015.