June 2022 - 16

CONTROLLED ENVIRONMENT AGRICULTURE
CEA poised to become a growth industry
By Eric Butterman
University of Georgia
Traditional agriculture is 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, " he
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.
" 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.
University of Georgia (UGA) horticulture Professor Marc van Iersel's research focuses on developing sustainable and
cost-effective ways to ensure that crops - including turnip plants in a grow room at his greenhouses - get the amount of light
they need. Photo: Andrew Davis Tucker/UGA
" There was no one taking advantage
of controlling light precisely in
greenhouses, " van Iersel said. " We found
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, that 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 system.
Predicting sunlight
" We're focused on control algorithms
VEGETABLE GROWERS NEWS
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 electricity prices.
You don't have the same electricity price
over the course of the day. I believe the
latest estimate from the Department of
Energy has the United States spending
about a billion dollars a year on electricity
to provide light for crops that are grown
in controlled environment agriculture. "
The responsiveness built into the
Candidus algorithm has a significant
effect on growers' return on investment.
" You make a system that cuts the cost
by 20% overall and that makes a critical
financial difference, " van Iersel said.
Among the most challenging parts of
the work is convincing growers who have
operated in a certain way for decades
that a new system can provide real value
to them.
" Many are reluctant to change things,
but some growers love trying new
ways, " van Iersel said. " When you see
more people doing well from trying
something out, then you tend to feel
more comfortable. "
Managing hydroponic
systems
In August 2021, Rhuanito Ferrarezi
was hired as an associate professor of
controlled environment agriculture in the
UGA-CAES Department of Horticulture
to leverage his expertise in production
to help strengthen research capacity in
controlled environment agriculture.
A main area of his work involves
improving irrigation, nutrition and
cropping systems, focusing on vegetables
and ornamentals.
" My lab is trying to figure out what
management systems should be used
in hydroponic systems for controlled
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environment agriculture, " said Ferrarezi.
" We also have a focus on figuring out how
we manage the fertilizer solutions in a
controlled environment to bring a benefit
in using less fertilizer for production. "
'Like a blood test for a plant'
One of the innovations Ferrarezi is
working on is related to sap analysis,
which uses leaf samples or soil substrate
sampling to determine nutrient content
in plant tissue.
Horticulture Associate Professor Rhuanito
Ferrarezi works to improve irrigation,
nutrition and cropping systems in
controlled environment agriculture.
Photo: Sierra Cannon/UGA
" It is like a blood test for a plant, " he
said. " We provide a snapshot of what is
going on with the crop over a growing
cycle. In a controlled environment, we
have the ability to grow a crop quicker
than out in the field. We can actually
monitor the nutrient content inside a
plant in real time and growers can either
increase or decrease the fertilization
based on those results. "
Ferrarezi believes that controlled
environment agriculture will continue
to attract increased attention from
industries, with good reason.
" They are looking for ways to
fine-tune production and controlled
environment agriculture can help lead
the way, " he said. " It's an exciting time
to be working in this area. "
UGA is a member of a consortium of
land-grant institutions in the Southern
region of the U.S. committed to finding
workable solutions that conserve our
natural resources, feed a growing world
and improve our quality of living. VGN

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June 2022

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