Top Story, April 15, 2015
Both studies LED effect on greenhouses with NJAES
By RICHARD SKELLY
NEW BRUNSWICK — Experiments with LED (light emitting diode) lighting being conducted at the New Jersey Agricultural Experiment Station and a rubric of other universities around the country are forging a path for farmers to run their greenhouse operations more efficiently.
Dr. A.J. Both is leading the experiment processes at Rutgers University’s Department of Environmental Sciences. Both, raised in the Netherlands, is an Extension specialist whose expertise is in controlled-environment engineering and biological resource engineering.
“Typically in greenhouse lighting, we use high pressure sodium lamps or metal halide lamps, not fluorescent lamps. LED lighting is a relatively new light source and a new technology we’re starting to use, hopefully as a replacement for other forms of lighting,” Both said of the experiments, which are being conducted at the experiment station. Other participating universities in the study include the University of Arizona, Purdue University, and Michigan State University.
“We hope (the LED’s) will prove more efficient, leading to less energy consumption for the same amount of light produced,” Both explained in the library of one of several buildings where he conducts research.
Before coming to Rutgers’ School of Environmental and Biological Sciences, Both earned his Ph.D. at Cornell University in New York.
“I grew up in the Netherlands, not on a farm, but I worked on a farm, in the north, in Friesland Province,” Both said.
He studied at an agricultural university, Wageningen, where he received both his bachelor’s and master’s degrees. He came to Rutgers in 2000.
“My area is not specifically re-engineering plants or animals, but looking at how we can manipulate the environment so that plants and animals can produce better yields, or in the case of animals, be healthier and happier.”
In biological resource engineering, “we look at the natural environment and see how it can be used for our benefit, all the while making sure we do that sustainably, so we don’t damage the environment for future generations.”
Most people are familiar with LED lights as they are used in many new model cars and some household goods and Both pointed out most stop lights and many tractor trailers use LEDs.
“You can see the dots,” he said.
The USDA has funded the research going on at the experiment station and the other universities. Both stressed many researchers are contributing to the project.
“We have many good people working on using supplemental lighting to boost photosynthesis and boost plant growth and also use lighting for manipulating the day light. For some ornamental crops, it’s important to have them flower at a certain time of year,” Both noted.
The advantage of using LED lighting in greenhouses and other controlled environments, Both said, “is that we can manipulate the spectrum and change the colors to mimic what sunlight is producing. We can manipulate the colors or select those colors that we know plants are most sensitive to. Plants are most sensitive to the blue and red colors for photosynthesis, so it’s a combination of red LEDs and blue LEDs, when you combine those colors, you wind up with this purple-ish or magenta light.”
Because other scientists have discovered how to manipulate the spectrum using LED lights, a whole new field of research has opened, he said, noting LEDs can be designed to produce a specific color of light and manufacturers can buy the specific colors they want and put them into that unit.
“We are part of a group doing this research, so we have divided our activities to speed up plant growth, and my role is more on the technical side. I have a setup here that is able to measure light output and what we’re really looking at here is efficiency.”
Scientists have worked on improving the efficiency of LED lighting since the technology began in the 1970s, Both said.
In his other lab, Both makes use of an integrating sphere, a large ball, to measure the amount and type of light from LEDs.
The floor of the walk-in-closet-sized ball can accommodate various types of plants.
“Most lamps produce some amount of light and some amount of heat, which is waste. We’re looking at the types of light most useful for photosynthesis,” he said, noting he can now measure the full distribution of light over a given surface area.
Sitting in the station’s library, he pointed up to the fluorescent lights in the ceiling.
“Most people have a very difficult time distinguishing between light intensities,” he said. “Plants, on the other hand, are very sensitive to it. You will quickly notice there is not enough of the right kinds of light with plants in here,” he said, adding “we as humans can’t see it and don’t notice it, but the plants do notice it and they are affected by it.”
Given that the efficiency of LED lighting technologies keeps gaining momentum, “I think most growers will eventually be switching over to LED lighting for their greenhouses,” Both said, “because it results in higher efficiencies and lower power bills to grow more plants.”