Crops in competition: how drier air is stealing moisture

Food crops competing with air for moisture CTV London's Gerry Dewan speaks with a Western University researcher looking at atmospheric drying and what it means for growing food.

London, Ont. — When people hear the word ‘drought’ what comes to mind is dry soil, with plants struggling to get moisture from that soil.

But a newly published paper focuses on the moisture being pulled away from plants due to drier air circling the earth. Air is competing for moisture and it takes it from the plants.

“Plants take water up from the soil, from the roots, and they transported it to the leaves," says Danielle Way, an associate professor in the Western University Biology Department. “The water is lost through little holes in the leaves surface into the atmosphere. The drier the air is the more moisture it sucks out of it.”

Way co-authored the paper with researchers from the University of Minnesota, which has been published in the journal Global Change Biology.

Way says crops, and non-crop plants, will suffer as drier air draws off moisture when they’re well irrigated.

“When plants are exposed to this higher atmospheric drying they’re shorter, they have fewer leaves.”

Prof. Danielle Way (Source: Western University)

Way says climate change continues to warm the air, and warmer air seeks more moisture.

“We measure that as something we call ‘vapour pressure deficit.’ That’s just, basically, how much water does the air want to suck out of anything that has moisture near it to compensate for not holding has much water as it could.”

She says that, while we take note of more visible indicators of climate change impacts like wildfires, flooding and melting polar ice caps, continued depletion of growing conditions may have a more immediate global impact.

She says it’s another reason why there needs to be action on climate change.

“That’s really where these sorts of changes come in, moving to a green economy where we’re not using fossil fuels and we’re also minimizing how much we change how we use our land. You know, deforestation; these sorts of issues.”

Way says progress has also been made toward creating more drought-resistant crops.

“That’s the sort of thing we can build into breeding programs, to get those traits into other crops.”

The analysis had a number of funding partners including the Canadian Natural Sciences and Engineering Council, the U.S. Department of Energy, the Australian National University and research councils representing wheat and soybean growers in Minnesota.