Imagine a fertilizer that stays in the ground until plants need to access it, instead of being washed away or giving plants more nutrients than they can handle.
That’s what Carleton University chemistry professor Maria DeRosa and adjunct professor Carlos Monreal are developing: a smart fertilizer that waits to release its nutrients until crops tell it to do so. It’s a technology that could have great benefit for the environment and human nutrition. Currently, unused or excess fertilizer often ends up in lakes and water ways where it creates algae blooms. A more efficient and cost-effective fertilizer can play a leading role in increasing crop yields and addressing malnutrition issues, as well as reducing the amount of fertilizer that farmers need to use, resulting in cost savings.
“If a crop isn’t ready to take up fertilizer when it is applies, it is wasted and it’s estimated we waste about $1 billion per year in unused fertilizer,” says DeRosa. “Our goal is to make fertilizer smart so that it delivers its nutrients to a crop only when the crop needs it.”
To do this, DeRosa uses aptamers, which are small, single-stranded nucleic acids that can bind to large or small target molecules. Her research involves identifying these aptamers, which are the “keys” to finding which DNA sequences will bind to the target molecules. In human medicine, for example, this approach is starting to be used to detect damaged cells and distinguish them from healthy ones so that therapy is only delivered to the diseased cell. Crops like wheat and canola will release chemical signals when they need nitrogen.
It was through partnering with Monreal, who is also a research scientist with Agriculture and Agri-Food Canada, that DeRosa and her team learned the identity of some of those signals – which allows DeRosa to program the coating of special biodegradable fertilizer capsules she’s developed to release the nutrients only when the plants need it.
“For example, if we place the fertilizer into a coated, biodegradable capsule, the coating will protect the fertilizer until the signal arrives from the plant that it needs fertilizer. That signal will hit the aptamer in the coating, break it down and release the fertilizer,” DeRosa explains, adding that the capsules protect the fertilizer from being washed away or damaged by extreme temperatures, but allow the nutrients to be released over time as the plants need them.
Following successful development of the coating and capsule and lab-based testing, DeRosa and Monreal are now moving their concept into a greenhouse setting to see how well it performs with real soil and plants. If successful, DeRosa says this development could open up a whole new field of using nanotechnology and biodegradable polymers to help feed the world’s growing population, projected to surpass nine billion by 2050.
This project has received support from Coop Fédérée and Agrium, as well as Agriculture and Agri-Food Canada and Alberta Innovates Bio Solutions.