IEEE Spectrum June, 2013 - 43

growing it

I m ag I n e th e h a n g I n g g a r d e n s o f Ba By lo n updated for
the 21st century. For Columbia university ecologist dickson
despommier, among others, putting farms inside high-rise buildings could usher in an era of industrial-scale urban farming. These
steel-and-glass greenhouses would tower above megacities, providing cornucopias for the future. At least that's what the proponents' 3-d renderings suggest. But nobody has yet built one to
test the concept, and it's possible nobody ever will.
Many experts are deeply skeptical, for a simple reason: Inspiring
as these hypothetical structures may be, vertical farms-at least
the skyscraper variety-don't match the demands of photosynthesis. That is, they don't provide adequate light.
Lucky plants with a window office would receive enough photons, but most would require artificial illumination, which doesn't
do the best job of replicating photosynthesis-fueling wavelengths.
electric lights also require power, and there isn't yet a green source
capable of providing it, at least not without raising the price of
lettuce to skyscraping levels.
"We do not have a technology today that can artificially light
plants in an economically acceptable or carbon-efficient manner,"
says Ted Caplow, an environmental engineer who founded
BrightFarms, an urban-greenhouse company based in new
York City.
Yet Caplow is quick to add that the disneyesque world-oftomorrow notion of farming inside towering buildings serves a
purpose. According to him, various farm-in-the-sky renderings
have nourished the imagination of urban agriculturists who have
come up with more practical arrangements: rooftop greenhouses
and agriculturally repurposed buildings of just a few stories. And
many such urban greenhouses now exist.
how resource-efficient and economic today's urban agriculture
can be remains to be seen, but even if it proves commercially successful, don't expect these operations to sprout into skyscrapers.
Practical facilities will probably never match the audacious concepts kicking around. "It's important not to mistake one for the
other," says Caplow. -BrAndon KeIM

Yet Mitchell and his father felt the system could be even more
exact. Because it relied on RTK readings to determine acceleration, it would switch the spray rate about one second after the
sprayer's speed had actually changed. "There was a lag," Mitchell
says. "So when you'd be speeding up or slowing down rapidly, like
you do in small fields, you'd always be putting on the wrong rate."
The Mitchells solved this problem by feeding data from the driver's
joystick accelerator to the logic controller. Then they programmed
the system to anticipate speed changes based on the driver's commands. So by the time the signals reached the drivetrain, the nozzles had already adjusted. "We're now getting to the point where
every square meter of the field gets the target rate," Mitchell says.
Many of the precision innovations that the Mitchells have adopted or built themselves are no longer unique. "There was a
time it seemed we were dragging everyone along," Mitchell's
father, Wade, says. "Now we can't keep up."

Manufacturers of automated agricultural equipment now offer
all sorts of bells and whistles, including various rate controllers
and yield monitors. More and more they are taking advantage
of wireless technology. John Deere, for example, is developing a
suite of products under a strategy it calls FarmSight that let largescale operators remotely monitor fleets of machines over a cellular
network. "The human-technology interface hasn't yet been mastered in agriculture," says Tony Thelen, operations director of the
company's Intelligent Solutions Group. "Our efforts are to make
data collection and decision support 'walk-up' easy."
Yet worldwide, farmers like the Mitchells are still a minority. And
persuading others to embrace precision management, particularly
in the developing world, will take more than smarter tools, says Jerry
Hatfield, laboratory director of the National Laboratory for Agriculture and the Environment. "I don't think we're technologically limited," he says. "I think we're human limited-not from an intellectual
incapacity but from the will to adopt these things."

" h e i S S ay i n g p r e c i S i O n a g r i c u lt u r e i S j u S t a t h e O r y," e z r i n m O h d
Husin translates for a Malaysian rice farmer who goes by the name
Jailani. They stand on the bank of an irrigation canal overlooking Jailani's paddy fields, where workers are busy "transplanting"
little carpets of nursery-grown seedlings into the soaked earth. It
is a steamy day in February, and Jailani wears knee-high rubber
boots and a brimmed cotton hat. Ezrin, whose collared shirt is
embroidered with the words Technology for Precision Agriculture,
adds, "He is saying he is a farmer and he knows better than theory."
Ezrin works for the Smart Farming Technology Research Centre
at Universiti Putra Malaysia, a short drive south of the country's
capital of Kuala Lumpur. Its modest staff includes some of the
few engineers in the world who have had success bringing precision practices to community farmers. In Malaysia, as in many
developing nations, small family farms produce the bulk of the
country's staple crop. But for decades, Malaysian paddy farmers
have grown only 70 percent of the rice Malaysians eat. "If grain
prices rise globally, or if for any reason Thailand refused to export their rice, we are in trouble," Ezrin says.
His fears are not merely hypothetical. In January 2008, a sudden spike in food and fuel prices triggered a worldwide cascade of
rice hoarding. While exporters such as Egypt, India, and Thailand
stockpiled their surpluses, Malaysia and other importers found
themselves lacking. Not long after the "great rice crisis" ended
that May, the Malaysian government set an ambitious goal to become wholly self-sufficient in rice by 2015.
In five years, though, the country has made virtually no progress toward reducing its dependency on foreign grain. Ezrin and
his colleagues believe the reason is simply that the government
hasn't applied the right solution. "If you implement precision
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Table of Contents for the Digital Edition of IEEE Spectrum June, 2013