UMaine Irrigation Research to Advance Water Conservation, Efficiency
Contact: Stephanie Burnett, (207) 581-2937
ORONO, Maine — A University of Maine horticulturist is using a novel moisture sensing system to monitor and control water delivery to plants to see exactly how greenhouse conditions affect ornamental plant productivity and health. The research is intended to help Maine growers and others economize on water and energy use, and produce better crops in the process.
In a quonset greenhouse behind UMaine’s Libby Hall, one or another of dozens of small black solenoids click on and off every 20-30 seconds at the command of sensors embedded in selected leafy green alumroot plant pots. Researcher and assistant professor of horticulture Stephanie Burnett explains that the moisture sensors wired to solenoids control and track plant watering.
“We have lots of environmental sensors that can track climate in the greenhouse,” she says. The sensors compare the shifts in plant water needs as light, temperature and humidity change from minute to minute. “In addition to that, we have a counter in our data logger that counts how often water is turned on or turned off.”
Most greenhouses have inexpensive light and temperature sensors, she says, but since moisture sensors can cost upwards of $60 apiece, that’s often too expensive for many small, family-run greenhouses to buy more than a few. Burnett, whose research interests include improving the efficiency and sustainability of ornamental plant production and irrigation technologies, hopes to produce a mathematical model to advise growers when and how much to water, based on soil moisture.
“Many growers guess, depending on the soil conditions, or by feeling the soil or gauging the weight of a pot,” she says. Within a few months, she adds, “I’ll have some recommendations for how much water specific plants use and a somewhat reliable model for some of these crops to determine how important the environment is for the crops.”
That’s important, Burnett says, because the landscaping industry brings about $353 million to the Maine economy each year, and ornamental plants are a significant part of that industry. It is one of the fastest-growing industries in Maine, according to economist and small business expert Jim McConnon, a Cooperative Extension specialist and professor of economics.
“It’s kind of a hidden industry,” Burnett says. “Nationally, it could be as high as $4 billion. Most growers in Maine are just mom-and-pop businesses, but they do hire a lot of people so they create a lot of jobs.”
From a global perspective, she adds, irrigation of agricultural and horticultural crops uses about 60 percent of the world’s water supply. With increasingly limited availability of clean water, a sensor-based irrigation system can substantially reduce water waste and still produce robust crops.
Burnett’s two-year research project is being funded by a modest grant from the American Floral Endowment. She says many research institutions are using sensors to monitor the environment inside greenhouses, but using moisture sensors to automatically trigger irrigation is something being done “by only a handful of institutions in the U.S.”