Antidote to Fertilizer Inefficiency

08:57AM Dec 06, 2014
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Breakthrough offers synchronicity of nutrient need and release

Imagine a day on the farm when a seed is planted alongside a fertilizer pill. Inside the small pill is a season’s worth of plant food perfectly tailored to the crop.

Initially, the idea of a lifetime nutrient pill seems absurdly futuristic, but such criticism is tempered by advances in fertilizer technology.

Researchers Carlos Monreal and Maria DeRosa are close to achieving a nutrient breakthrough with tremendous ramifications for global agriculture. Harnessing nanotechnology, the Canadian duo is coating fertilizer with a polymer that detects chemical signals from plant roots and reacts by releasing nitrogen as needed to the crop. Essentially, intelligent fertilizer is the synchronicity of nutrient need and release, an antidote to environmental harm and nitrogen inefficiency.

In 2008, Monreal, a scientist with Agriculture and Agri-food Canada, began to research how plant roots and soil microorganisms communicate. “It’s a language of chemical signals where the plant alerts the soil microorganism during growth stages about its need for nitrogen.” 

Monreal’s discovery of the chemical signals used as a trigger mechanism for nutrient feeding allowed nanotechnology to be used and for subsequent collaboration with DeRosa, an expert in biosensors with Carleton University. 

Biosensors expert Maria DeRosa, Carleton University, Ottawa, Ontario, believes intelligent fertilizer might be ready for farmers in 10 years.

They set out to find a synthetic system capable of detecting plant chemical signals and incorporate it into a fertilizer product. “We wanted to put a built-in nano-biosensor around fertilizer pellets that detects the signal coming from plant roots and then releases nitrogen only as needed,” Monreal explains.

DeRosa used aptamers, synthetic strands of DNA that distinguish  chemical signals, to recognize a signal coming from a plant root. “We’re incorporating aptamers into a coating that protects fertilizer,” DeRosa says. “When an aptamer, as part of a fertilizer coating, gets a root signal, it allows the coating to suddenly become more porous and release nitrogen.”

Monreal believes intelligent fertilizer technology won’t affect fertilizer pellet size. “If you look at the urea sold in the fertilizer market today, the particles are normally 1 mm to 2 mm spheres,” he says. “We think the size and shape of the product will remain. However, the change will involve the polymer film coating, about 100 
nanometers thick.” 

The polymer coating contains biosensors that detect chemical signals released by crop roots and respond by releasing nitrogen via nanopores. When the crop chemical signals cease, most, if not all, of the added fertilizer is taken up by the plants.

Repeated studies show nitrogen efficiency use in crops ranges from 30% to 50%. Monreal believes intelligent fertilizer will allow farmers to increase nitrogen efficiency up to 85%, or even higher. “For every $100 a farmer invests in fertilizer, only $30 to $50 is used by the crop. The rest, up to $70, is lost to the environment,” Monreal notes.

Inefficiency uptake occurs as nitrogen is exposed to the elements and lost to leaching or the atmosphere. Farmers are currently forced to apply surplus nitrogen in anticipation of inevitable losses to come. Those nitrogen losses contribute to higher input costs for farmers and environmental damage.

“There’s nothing inherently bad for the environment in fertilizer ingredients. The problem is there’s no way to protect nitrogen from getting washed away and taken up in the atmosphere,” DeRosa explains. “If we had a way to protect nitrogen and only release it when the crops need it, the result would allow farmers to apply only half as much nitrogen—or maybe even less.”

Although focused on nitrogen, DeRosa believes all nutrients will eventually be in the intelligent fertilizer fold. The key for different nutrients and fertilizers is discovering their distinct chemical signals. Deciphering the signal released when a crop needs phosphorous or potassium would allow researchers to create corresponding aptamers and place them in polymer coatings.

Monreal and DeRosa’s research has reached the polymer coating stage. They’re testing various bio-degradable polymers and application methods (capsules and films) for fertilizer pellets and moving toward a prototype for field testing in 2016. Their efforts have been focused on wheat and canola, but Monreal emphasizes fertilizer companies will be able to tailor intelligent fertilizer technology for any specific crop—or even engineer generics for use on multiple crops.

“Imagine a typical fertilizer plant that produces urea. The concept is to place a receiving box at the end of the production line, and when the urea granules come out, the nano-biosensor coating will be applied,” Monreal describes. “Fertilizer companies wouldn’t need to change their processing lines but simply add a step. After the fertilizer product is finished, farmers will be able to use the same application equipment they presently use.”

Intelligent fertilizer’s nanotechnology concept has the potential to be used across vital segments of the agriculture industry. Biosensor and polymer advances might be applied toward pest prevention or plant diseases. Would intelligent fertilizer science extend to intelligent pesticide? 

As a visionary on intelligent fertilizer for nearly four decades, science is finally catching up to researcher Carlos Monreal’s imagination.

“The expansion of this technology lends itself to coating pesticides,” DeRosa explains. “There is evidence that plants release certain signals when under attack from a particular pest or disease.”

The intelligent fertilizer concept fits seamlessly with the efficiency demands placed on agriculture by a burgeoning global population expected to clip 9 billion by 2050. Monreal believes intelligent fertilizers will become standard in agriculture as environmental and economic concerns grow over nitrogen inefficiency. 

“The benefits of a highly efficient product that satisfies farmers and environmentalists will cut across agriculture in general,” Monreal says. “If we are successful, I think intelligent fertilizer technology will become a major practice in agriculture and be adopted worldwide.”

If Monreal and DeRosa succeed, the agriculture industry will likely snap up fertilizer products that recognize crop needs and respond accordingly. They are hopeful intelligent fertilizer technology will be field-ready for farmers within 10 years. 

“After this nanotech science is perfected, it will bring a lot of benefits to agriculture,” DeRosa says.

To learn more about how technology will advance production agriculture in the next 10 years, visit