Chemical signals from the plant tell the coating to dissolve and allow roots to take up fertilizer
Canadian researchers are making progress on a smart fertilizer that could save farmers hundreds of millions of dollars a year.
“The idea was kind of science fiction at the beginning and only over many years of research in the lab are we starting to get to the point now where we see this idea can really work,” said Maria DeRosa, associate professor of chemistry at Carleton University.
“So it’s kind of awesome.”
The idea was to create a nitrogen fertilizer that only deploys when it is told to by a plant.
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Carlos Monreal, a research scientist with Agriculture Canada who is working with DeRosa on the project, said 50 to 70 percent of the nitrogen fertilizer applied to crops typically ends up in groundwater, is washed away into rivers and lakes or escapes into the atmosphere.
“There is tremendous inefficiency,” he said.
The researchers estimate Canadian farmers waste $1 billion a year on unused fertilizer.
Monreal has been searching for a way to reduce that waste since 1977. His search led him to DeRosa about 10 years ago when a mutual student told him about the work she was doing on nanotechnology.
DeRosa said Monreal was in-trigued by her efforts to find a way to deliver drugs to humans in a targeted way using nanotechnology.
He felt her research could be combined with the work he was doing with plant exudates.
“Exudates are basically these chemical signals manufactured inside the crop that get spit out of the roots,” she said.
Monreal discovered a dozen exudates that provide signals to microbes in the soil to start oxidizing nitrogen for uptake by the plant. The exudates in turn provide the microbes with the carbon they need to grow.
DeRosa was asked to develop a coating that would prevent fertilizer pellets from being dissolved by water until the plants send out a signal. The smart part of the coating is called an aptamer, which responds to the exudates.
“It’s basically synthetic DNA we make in the lab and it can recognize and bind and respond to all different types of molecules,” said DeRosa. “The coating then responds by becoming either more permeable, so more fertilizer can leak out, or (by) breaking down completely.”
The remainder of the coating is a biodegradable polymer.
The researchers have developed a prototype of the product and hope to test it in a greenhouse setting next year.
They should know by the end of next year whether the product is ready to move on to field testing. If everything goes well, farmers could be buying smart fertilizer before the end of this decade.
Monreal said the product could boost nitrogen efficiency rates to 85 percent from 30 to 50 percent today.
“For the farmer, it would mean that they can apply 40 to 50 percent less fertilizer,” he said.
Canadian farmers spent $4.97 billion on fertilizer and lime last year, according to Statistics Canada.
“That translates into some significant savings for the farmer,” said Monreal.
The research team is developing a “technology box” that would be attached to the end of the production line at a nitrogen fertilizer plant. It would apply the coating to the urea pellets.
The pellets will be the same shape and size as regular urea, so farmers can use existing equipment.
DeRosa said the initial coating they are working with releases the fertilizer all at once, but researchers are also working on an advanced coating that opens up, release a little bit of fertilizer and then closes and waits for the next plant signal.
Smart fertilizer will help growers with their bottom line and improve the tarnished environmental image of farming.
“(Fertilizers) need to end up in the right place, which is inside the plant where they can do their job. If they end up other places, then they feed other things like algae causing algal blooms in waters,” he said.
