*

Wildfire smoke helped counter extreme heat, benefitting

this

year's canola crop

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High temperatures and scorching sun can devastate growing

season

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More research is needed on smoke's impacts on crops,

experts say

By Ed White

ELM CREEK, Manitoba, Sept 23 (Reuters) - Colin Penner,

who farms about 3,700 acres an hour's drive north of the U.S.

border, crunched up a handful of plump canola pods and blew the

chaff into a stiff prairie breeze. A small pile of tiny black

seeds remained in his palm.

Last summer, high heat and harsh sun scorched canola's

yellow flowers and ruined their pollen, knocking down yields

across Western Canada. This summer, smoke from nearby wildfires

shrouded the July skies and protected Penner's young crop from

the sun's burning rays, resulting in more seeds per pod and more

pods per plant.

"Look at all these pods," he said. He would wait to see

what the harvest brings, but "smoke will likely be a positive

thing."

PROTECTION FROM EXTREME HEAT

As Canada's western provinces experience the second-worst

wildfire season in decades, driven by hotter and drier

conditions due to climate change, some canola farmers say they

are seeing an unexpected benefit to the hazy summer skies - so

long as they occur in July, when the crop is flowering.

The smoke is shielding the delicate flower petals and pollen

of canola plants from intense heat and sunlight, mitigating the

impacts of a drought which continued through most of this

summer.

The finding contrasts with scientists' understanding that

extended periods of heavy smoke have largely negative impacts on

crop yields and food quality.

Reuters spoke to dozens of farmers and 10 crop experts who

said the smoky skies of midsummer had mainly positive impacts

for canola - although the experts cautioned that more research

is needed.

Bruce Burnett, a crop analyst with the Western Producer Markets

Desk trade publication, told Reuters that the smoke's cooling

effects countered high daytime and nighttime temperatures, which

can hurt the crop when it's flowering.

Canada is the world's largest producer of canola, growing 21

million acres in a band along the country's vast northern

forests. Its seeds are crushed to make cooking oil, biodiesel

and animal feed.

Canola, which is grown mainly on the cool northern plains of

North America, Europe and China, and as a winter crop in

Australia, does not like it hot. Scorching heat can melt its

pollen, preventing fertilization and seed production. Harsh

sunlight can burn off flower petals.

"We've had a couple of really hot Julys where we've had

temperatures above 31C (87.8°F) and that's where the damage

occurs," said Curtis Rempel, vice president of crop production

and innovation at the Canola Council of Canada.

Smoke can lower temperature and dim sunlight, he said.

SCIENTISTS REVISITING IDEAS ABOUT SMOKE

The United Nations' climate science panel, the

Intergovernmental Panel on Climate Change, in 2022 forecast that

a hotter world with shorter winters would lead to longer and

more extreme wildfire seasons.

Canadian government officials said in August that wildfires were

already growing longer and more intense as winters become

shorter, and spring, summer and fall warmer.

Four of the crop experts who spoke to Reuters said smoke is

probably mostly bad for North America's biggest crops, like corn

and soybeans, reducing heat and sunlight which the plants need

to grow.

In California, smoke from wildfires has devastated wine grape

production, with severe damage in 2017 and 2020.

In Ohio, researchers found mixed effects. While the smoke

reduced light and lowered temperatures, average yields of corn,

soybean and wheat reached a 10-year high, the researchers found.

The Canadian government is launching research next year on

how wildfire smoke is affecting canola, wheat and barley, said

Raju Soolanayakanahally, a senior researcher at Agriculture and

Agri-Food Canada.

Despite farmers' accounts of some benefits to this year's

canola crop, smoke can also slow and weaken crop development,

Soolanayakanahally said. The haze can degrade the chlorophyll

that is essential for photosynthesis and reduce the efficiency

of enzymes that are critical to plants' development.

An industry review of existing research on the effects of

smoke on U.S. corn also found a mostly negative effect.

However, Mark Jeschke, Agronomy Manager at Corteva Agriscience's

Pioneer Seeds and author of the study, told Reuters

further research was needed on how ground-level and airborne

smoke affect corn when it is pollinating and maturing. "The

timing of a stress event can matter a lot."

SMOKE-TAINTED WINE

In 2020, when more than 8,000 fires tore across 4.3 million

acres of California, most vineyards escaped direct damage from

the flames. But vintners later discovered the grapes produced a

slurry tainted by a foul taste and smell, making it unusable for

wine. The term "smoke taint" became part of the wine lexicon.

Up to 325,000 tons of wine grapes worth more than $600

million were ruined that year, according to the California

Association of Winegrape Growers.

The industry and researchers have been experimenting with

treatments to remove smoky compounds from fermented grape

slurry, and testing a spray that would prevent

grapes-on-the-vine from absorbing smoke.

"We still have so much to do," said Natalie Collins, the

president of the California Association of Winegrape Growers.