Nano-technology | Researchers developing ‘bio-sensing’ fertilizer
It’s been a rule in farming for decades: crops use only 30 to 50 percent of the nitrogen applied to the soil.
Carlos Monreal, an Agriculture Canada research scientist, would like to abolish that rule.
After several years of experiments and study, Monreal and his colleagues have developed a prototype technology that senses when a growing crop needs nitrogen and releases the appropriate amount of nutrients to feed the crop. The technology remains in the greenhouse phase but the basic concept looks promising and may dramatically increase nitrogen use efficiency (NUE).
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“We think with this technique we can bring up (NUE) upwards to 80-85 percent,” Monreal said from his Ottawa office. “If we are successful this would mean a big change in fertilizer technology.”
With funding from Alberta Innovates Bio Solutions and Agriculture Canada, Monreal and scientists at the universities of Carleton, Alberta and Ottawa have been studying the potential of nano-technology in fertilizers since 2008.
Agrium and other companies introduced polymer-coated fertilizers several years ago. The coating reduces the amount of nitrogen lost to the environment and releases the fertilizer at a certain rate, depending on temperature and soil moisture.
Monreal said his technology improves upon that because it will synchronize the release of nitrogen with crop uptake.
Through his research Monreal has learned that plant roots release certain chemicals and those compounds act as a signal.
“We know there is communication between plant roots and soil micro-organisms…. The language of this communication is chemical signals.”
Monreal and his colleagues have conducted lab experiments to detect and monitor the chemical signals from the roots. Some of those signals tell micro-organisms to mineralize more nitrogen from the organic matter in the soil.
The scientists grew canola and wheat in a greenhouse and used mass spectrometry to monitor the chemical compounds present in the soil, to measure how those chemicals vary throughout the growing season.
The scientists determined that certain chemicals appeared at higher concentrations in the soil at the exact time the crop needed more nitrogen.
“We found there are a few chemical compounds that follow the exact same dynamics of the nitrogen uptake,” Monreal said, noting some chemicals were specific to wheat and others were specific to canola.
“But we also have some signals or compounds that are common to both crops.”
Having identified chemicals that may be telling soil micro-organisms to mineralize more nitrogen, Monreal and his colleagues began the next stage of their research; developing bio-sensors to detect those chemicals in the soil.
“The idea is we can incorporate these bio-sensors to the polymer coating the fertilizer particles,” he said. “Then when the roots are exuding these compounds… the bio-sensors will… release nitrogen from the fertilizer product.”
Monreal and his team have developed an early prototype of the bio-sensor, a thin polymer film covering the urea particle.
John Heard, Manitoba Agriculture soil fertility specialist, said folks in the fertilizer trade have realized it’s challenging to market generic urea and anhydrous ammonia
“I think the fertilizer companies have recognized what herbicide companies and others have, that product differentiation is kind of nice,” said Heard. “It’s good that (companies) are going to take some of these products and be more aggressive in the management of them.”
Monreal said farmers may soon buy fertilizers that are specific to a certain crop. One fertilizer might be used on canola and another for growing wheat.
“I think that will be a markets strategy by the companies,” he said. “They may want to specifically tailor (a fertilizer) for a given crop.”
Monreal’s soil sensing technology remains in the lab stage but it may only take five or six years to develop a commercial product.
