November/December 2022 - 19

CEA poised to
become a
growth industry
By Eric Butterman
University of Georgia
highly weather dependent, and many
producers of high-value crops are shifting
from field production to controlled
environment agriculture (CEA). That is
where the University of Georgia's (UGA)
Marc van Iersel comes in.
Van Iersel, the Vincent J. Dooley
professor of horticultural physiology
in the UGA College of Agricultural and
Environmental Sciences (CAES), defines
controlled environment agriculture as
both greenhouse production that relies
on natural sunlight and vertical farms
that use an electrical light source.
Responding to climate change
" One of the reasons a shift is happening
is that 90% of all leafy greens produced
in the United States are produced in
California and Arizona, " van Iersel said.
" That area is in a megadrought and there
is no end in sight. Because of this, they
may not really be able to have water
available to grow the crops in what is
essentially a desert. "
Controlled environment agriculture is
appealing to producers who are " looking
for production systems that may not use
as much water in controlled conditions
where you can get predictable, year-long
production, " he said.
In his 27 years at UGA-CAES, van
Iersel's research has focused on developing
sustainable and cost-effective ways to
ensure that crops get the amount of light
they need to grow.
 University of Georgia (UGA) horticulture Professor
Marc van Iersel's research focuses on developing
sustainable and cost-effective ways to ensure that
crops, such as these turnip plants in a grow room
at his greenhouses, get the amount of light they
need to grow. Photo: Andrew Davis Tucker/UGA
" The greenhouse has to respond to
weather conditions changing all the time, "
he said. " You have shorter fluctuations
from morning to afternoon to evening
and year-long fluctuations in many parts
of the United States in winter. You need
to adjust to it. "
Based on his research, van Iersel
co-founded Candidus, an agricultural
technology company, in 2017 with Erico
Mattos, who received his doctorate from
UGA in 2013. The company provides
lighting control systems that use a compact,
powerful industrial microcomputer to
monitor light sensors, calculate optimal
lighting conditions, and control the lighting
in controlled environment systems via a
local Wi-Fi network.
" There was no one taking advantage
of cont rol l ing l ight precisely in
greenhouses, " van Iersel said. " We found
 Horticulture Associate Professor Rhuanito Ferrarezi
works to improve irrigation, nutrition and cropping
systems in controlled environment agriculture.
Photo: Sierra Cannon/UGA
we could reduce electricity costs for
lighting by 30%, and given that, generally
speaking, electricity cost for lighting
is between 10% and 20% of operating
costs for greenhouses, which can reduce
operating costs by nearly half. "
The partners initially developed a
system that responded to real-time levels
of sunlight, but van Iersel has collaborated
with electrical engineers to improve the
Predicting sunlight
" We're focused on control algorithms
where we can now predict the amount
of sunlight we will likely get for the
rest of the day, which helps us make
better decisions on how much light we
want to provide, " he said. " We also
developed algorithms that allow the
lighting system to respond to changing

November/December 2022

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