More frequent severe droughts result in significant crop losses.

Christine Berkley is one of the biology students at the University of Bergen who has contributed significantly to the project. Credit: Paul Thorvaldson

Climate change has resulted in a rapid increase in weather events worldwide. NIBIO research scientist Pål Thorvaldsen is among the many scientists who took part in a large international drought experiment commissioned by the University of Michigan, suggesting that climate change could lead to more short-term extreme drought events. can cause

“Previously, short-term extreme droughts may have occurred every 100 years. According to some we can expect them to occur every five to 10 years in the future,” the researcher says.

The scientists examined ecosystems dominated by grasses and shrubs – both important grazing areas for livestock. The results showed that compared to areas with moderate drought, grasslands experienced an overall 60% reduction in plant growth during short-term extreme drought.

“It’s concerning to witness such a drastic reduction. in ecosystems that are critical to food production,” Thorvaldsen remarked.

Important to prevent pastures from drying out.

Scientists researched 170 locations around the world. The results revealed a significant reduction in plant productivity in the ecosystems studied after one year of severe drought.

“After just one year, the results showed a nearly 40 percent decline in biomass in the grass-dominated ecosystem. This is nearly double the decline seen in the shrub-dominated ecosystem, which saw a decline of nearly 20 percent. occurred. Serious for farmers who rely on pasture for their animals,” says Thorvaldsen.

“Having an element of shrubs or trees in pastures seems beneficial. It affects the microclimate and reduces radiation.”

Although severe droughts rarely occur simultaneously in all of Norway’s main agricultural regions, the research scientist believes that access to water systems may be important to ensure food supply in the future.

More frequent severe droughts result in significant crop losses.

Coastal heathland at Stourboya, six years after artificial drought with 90% coverage. Vegetation coverage is high, but one can see how some plants have wilted. Credit: Paul Thorvaldson

Preventing these ecosystems from drying out is critical to global food production, but also to climate accounts.

“Globally, the ecosystems we studied cover between 30% and 40% of the Earth’s surface and store more than 30% of Earth’s carbon. Plant production is a key driver of the carbon cycle. One of the. When the production of plants is reduced, there is a reduction in the co2 is absorbed from the environment,” explains the researcher.

“Understanding how plants and ecosystems respond. It will be very important moving forward.”

Norway’s coastal heathlands tolerate drought well.

The Norwegian research team was responsible for six sites across the country. These were all pasture areas dominated by coastal heathland heather, an evergreen dwarf shrub. At each site, the researchers set up nine cages measuring 3.5 x 3.5 m. Three of the cages were unroofed open control arenas. The other six cages had roofs with plastic panels with holes between each panel. In three cages the plastic panels covered 60% of the roof, and in three cages the panels covered 90% of the roof.

These transparent roofs were built 80 cm above the ground to allow light and air to reach the plants. Because of moisture infiltration from the surrounding area, measurements were made using soil moisture. meter

“Results from Norwegian coastal heathlands show that they are surprisingly resistant to drought. After three years of drought experiments, we could not detect changes in vegetation composition—even In areas of extreme drought where we reduced rainfall by 90 percent, there was no significant reduction in productivity either,” says Thorvaldsen.

“We could see that the plants were damaged by the drought and wilted much earlier in the fall. But when spring came, the plants were just as strong again.”

The Norwegian project was extended for another three years, and now the research team is starting to analyze the full dataset after six years of hard work. .

Provided by the Norwegian Institute of Bioeconomy Research

Reference: More frequent extreme droughts result in significant crop losses, researchers say (2024, February 20) February 20, 2024 https://phys.org/news/2024-02-frequent-extreme- Retrieved from droughts-result-significant.html

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