Heather McNairn Canada

Monitoring plant health from space

"Satellites can pass over large areas very quickly."

Heather McNairn was just completing her PhD when she watched the 1995 launch of Canada’s first RADARSAT satellite. Back then, no one could have predicted how important Canadian satellites would become to agriculture.


Now, Canada has three newly launched satellites that are being used to map crops and measure their health with a level of precision that is cutting edge.


“Canada has almost 160 million acres of total farmland – and boots on the ground can’t cover it all,” says Heather, whereas “satellites can pass over large areas very quickly.”


As a top research scientist with the Department of Agriculture and Agri-Food Canada, Heather works with a team to develop algorithms that turn the massive amounts of data collected from the satellites into useful information.


“This information has huge potential to help agricultural management and policy,” says Heather. “Especially with our new RADARSAT-Constellation Mission satellites, we can monitor floods, drought, pests and plant diseases.”


One of Heather’s recent projects has been to use satellite data to combat a devastating disease of the oilseed crop canola, caused by the fungus Sclerotinia sclerotiorum, which can develop if soils are wet for long periods when canola is flowering. Partnering with industry and other government researchers, Heather and her team have created a new method that uses satellite data to accurately predict the date canola plants will flower, which is the ideal time to apply fungicide if it’s needed. Other methods identify persistently wet soils and can tell if canola was previously grown in a field.


“Spores from the disease can survive over the winter, so if canola was there previously, it could be risky to plant it again next season,” Heather explains. “Knowing this information can help farmers plan their seeding and fungicide application, improving their chances of a healthy canola harvest.”


Canola generated farm-cash receipts of over CAD 9 billion in 2018, making it a top crop for Canada’s economy. The team is now working to adapt this method to other crop types, an important step towards protecting Canada’s food supply and economy going forward.