Wireless nitrate soil sensor could cut fertilizer use

A University of Oregon spinout company that has developed a wireless soil sensor to detect nitrate levels in fields that could help farmers reduce fertilizer use by up to 30 percent, has been awarded Oregon BEST commercialization funding to fast-track the product to the marketplace.

Because plants can absorb only so much nitrogen, approximately 30 percent of the fertilizer applied to North American soils is wasted due to over-application and runoff. With U.S. farmers spending $12 billion annually on fertilizer, the new supramolecular sensor technology, discovered by accident by chemists at the UO, could lead to significant savings in fertilizer purchases, as well as in labor and fuel costs associated with fertilizer application.

It could also help reduce pollution from fertilizer runoff.

"In addition to the potential economic savings for farmers, our sensors will also help reduce groundwater pollution caused by excess nitrates that flow from cultivated fields into streams, lakes and oceans," said Calden Carroll, CEO of SupraSensor Technologies. "Excess nitrates are what trigger algal booms that deplete oxygen levels and create dead zones in the water where nothing can live."

Carroll, who earned his PhD in chemistry from the UO in 2011, said nitrates are problematic in fertilizers because they are water soluble, so over-application can lead to nitrates being leached from the soil and into the water system.

The problem is so widespread that the National Academy of Engineering has identified managing the nitrate cycle in agriculture as one of 14 "Grand Challenges" for the 21st century.

Carroll discovered the molecule now used in the sensor "by accident" when he was a graduate student studying supramolecular chemistry the interactions between molecules with UO chemistry professors Darren Johnson and Mike Haley (all of whom are co-founders of SupraSensor Technologies).

"Calden's initial result was a happy accident," said Johnson, who is also an adjunct professor at Oregon State University. "We were trying to create a molecular probe to visualize the movement of chloride not nitrate through cells to aid research into drug discovery and understanding chloride transport mechanisms in general."

Although the research team knew they had discovered a molecular marker specific for nitrate, it wasn't until later that they realized the implications of the discovery in agriculture and launched the new company.

"How to take a chemical interaction and transduce an electrical signal has been a long-standing problem," said Carroll. "But when nitrogen binds to the molecule we developed, it fluoresces a cool color, and we're able to harness that electronic response to measure nitrate levels."

The researchers say the value proposition to their sensor product is the reduced time-to-data it offers farmers. Designed to mimic plant roots and be buried in the soil just below root level, the sensors provide real-time data about soil nitrate levels so farmers can immediately make adjustments to fertilizers and irrigation (applied together, this is called fertigation).

"Currently, obtaining this type of data requires taking multiple soil samples, which involves a lot of labor, and then the wait for lab results," Carroll said. "Our technology's real-time data would enable highly site-specific management of fertigation."

While the company is focused on precision agriculture at the moment, they have their sights set on broader markets.

"We're developing a technology that will allow us to expand into the gardening and home markets, as well as into industrial applications such as drinking water and wastewater monitoring," Carroll said. "Using a supramolecular interaction has the potential to improve a wide range of applications."

The $120,000 from Oregon BEST will support deployment and field testing of 150 sensor prototypes in 12 different geographical locations, in tandem with manual soil testing to ensure the data generated by the sensors is accurate over time and in different soil conditions. The company plans to test the robustness of the sensors throughout a growing season, starting this spring. It is currently seeking farmers of fertilized and irrigated crops willing to participate in the study.

"This project leverages an important scientific discovery and our regional strengths in agriculture to advance a technology that could prove to be transformational in reducing costs for farmers and pollution in our planet's water systems," said David Kenney, President and Executive Director of Oregon BEST. "Oregon BEST is happy to be able to help accelerate this effort."

The Oregon BEST funding is also enabling acquisition of equipment, including a UV-Vis spectrometer, and expansion of one of the analysis labs in the UO's CAMCOR facility that will aid future sensor development work at the university.

The company previously participated in the National Science Foundation's Innovation Corps (I-Corps) Program, winning the "Best Team" Award out of 25 teams that participated in the 6-month course. In addition to the Oregon BEST funds, the company was awarded a $180,000 National Science Foundation Small Business Innovation Research (SBIR) grant and a $250,000 Gap Grant from ONAMI.