NCNU pioneers LED applications for nighttime farming
The National Chi Nan University has refined an industrial LED lighting
system that not only produces lower levels of light pollution, but is
substantially more cost effective for raising crops at nighttime ─ specifically
for the plots of Manchurian wild rice tended by Taiwanese farmers.
Colloquially known as “water bamboo,” the Manchurian wild rice is not
grown for its grain but rather for its stem, which swells into a juicy gall
after the deliberate introduction of fungus spores. Nantou’s Puli Township, the
location of the university, produces up to 90% of Taiwan’s total Manchurian
wild rice output.
The township has devoted 1,800 hectares to this crop, producing a
staggering 45,000 tonnes per year to meet demand for the popular vegetable,
which is usually prepared by stir fry or grill. Over half of Puli’s wild rice
farmers now use artificial lights to boost growth through nighttime
Their choice of high-pressure sodium lamps, however, have contributed to
Puli’s “city of lights” fame, as the township is bathed nightly in a steady
orange glow that reflects off the clouded skies. Less than 5 hectares of these
lit paddies use LED lights.
LED towers, a cost-effective and eco-friendly solution
In partnership with Taiwanese nonprofit Industrial Technology Research
Institute and the Council of Agriculture’s Taiwan Agricultural Research
Institute, NCNU recruited Puli youth farmers in an experimental attempt to
study the effects of LED lights in wild rice farming.
The half-year project found no discernable difference in crop output, yet
recorded significant decrease in power usage and equipment depreciation. For
every plot of land, roughly measured as 0.096 hectare, electricity consumption
dropped by 80% in comparison to traditional sodium lamps.
NCNU researchers also re-hauled the LED lighting system design, from the
conventional flat and chessboard-like array to a nimbler, street lamp-esque
This innovation makes way for easier distribution of lighting, with each
plot of land requiring only 4 to 8 LED lamp towers to be affixed on the
sidelines of the rice paddy. Industrial machinery can also easily pass through
the wide spaces in between each tower.
At NT$2,000 per lamp, the NCNU’s design costs about the same as sodium
lamps to set up, but lasts for 7 to 8 years longer. Moreover, each tower is
retractable, meaning farmers can adjust height and light exposure depending on
crop growth, and lower the LED lamps when typhoon strikes.
Tsai Yung-pin, head of NCNU’s College of Science and Technology, noted
that the university hopes to expand its cooperation with local farmers, not
only in implementing cost-effective and eco-friendly LED towers, but also in
researching areas such as sustainable water procurement, byproduct and litter
management, and reuse of biowaste.