Last week, Yellowstone National Park’s heavy rains destroyed miles of roads, closing it and flooding nearby Billings (Montana). Millions of people in India and Bangladesh were affected by heavy monsoons this week. Record rainfall in southeastern China caused a deluge that resulted in landslides, and forced evacuations.
Flooding claims lives, ruins infrastructure and threatens agriculture—and jeopardizes food security. In a House Agriculture Committee hearing last week, U.S. Rep. Shontel Brown (D-Ohio) called recent Midwest flooding “devastating” and said flooding was “already affecting the way our farmers produce and distribute food.”
New research is now available to help farmers weather the storm. A May study published by Utrecht University researchers Plant PhysiologyThe study identifies a way to increase flood resistance in crops through the use of ethylene, a plant compound that aids in growth and ripening. The findings could lead to improved climate resilience in the global food supply due to the increasing vulnerability of agricultural land to flooding.
Scientists claim that the frequency of heavy rains has increased due to rising global temperatures. Some models show that the U.S. flood threat could rise by more than 25 per cent by 2050.
Flooding kills crops in a number of different ways—first, flooding traps gases in plants, limiting gas exchange and effectively suffocating them. The result is that plants, which depend on constant exchange of oxygen and carbon dioxide for their survival, can no longer grow or produce energy. Additionally, submerged plants suffer from increased production of reactive oxygen species, which are highly reactive molecules that can damage a plant’s DNA, leading to death of the crop.
Another gas that can be trapped in plants when they flood is ethylene. Importantly, ethylene has been shown in crops to increase their flood resistance. Researchers are now able to see how ethylene contributes specifically to flood resistance and have discovered that ethylene has multiple benefits in flooding plants.
“What is really exciting is there’s not just one answer, there are multiple answers,” said Sjon Hartman, an author on the paper, former Utrecht University researcher, and professor at the University of Freiburg.
In the experiment, Hartman and his colleagues applied ethylene to plants before submerging them underwater, then measured the plants’ response. The researchers found that ethylene assisted the plants’ ability to produce energy while underwater, acted as an antioxidant, and stopped root growth, allowing the plant to save energy.
Understanding plants’ response to ethylene, said Hartman, is the first step towards better breeding of flood-resistant plants, especially since agriculture in recent history has not prioritized breeding for flood-resistance in crops, favoring drought-resistant traits instead.
“We don’t necessarily select against [flood-resistance], but we don’t select for it anymore,” he said. “We are losing natural stress responses which might be very important for [crop] survival under climate change conditions.”
He said that potatoes and corn are the best crops to target because they are staple crops for most of the world and highly susceptible to flooding.
Extreme rainfall in the Midwest caused flooding along the Mississippi river during the spring and summer 2019. According to the National Weather Service the Mississippi reached its highest level since 2014. Many of its tributaries also set flood records. According to the U.S. Farm Service Agency. farmers were prevented from planting more that 19.6 million acres of farmland in this year’s extreme weather. Most of this farmland was located in the Midwest.
Farmers in the Midwest have had to deal with flooding since then. “Flooding almost always impacts farmers somewhere in the state,” said Ed Anderson, the senior director of research for the Iowa Soybean Association. “Anything we can do to manage short term, intermittent flooding … is going to become more and more important as the climate continues to change and we continue to have these extreme weather events.”
Chris Gaesser, a southwest Iowa corn, soybean and Rye farmer, agrees. Flooding, he said, “seems to happen a lot more than it used to.”
“We live near a lot of rivers and stuff,” said Gaesser. “You’ll have some [crops]Nearly every year, creek and river bottoms are submerged. And it’s just one of those things we can’t do a whole lot about.”
Gaesser uses cover crops and no-till agriculture to manage water on his farm. This creates a soil structure that allows water flow more easily from the cropland. Farmers who farm in low-lying or near rivers might also be interested, however, in flood-resistant plants.
Demand for flood-resistant crops, said Anderson, will “only increase.”
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Purdue University’s professor of plant biology Michael Mickelbart believes that breeding plants for enhanced ethylene response could help farmers and flood resistance. But engineering crops for specific traits can often be more difficult than it seems.
“The trick with these approaches is always in the degree to which we alter the responses,” he said. “Very small shifts in response may have no ‘real world’ effect, and extreme manipulation of stress responses might result in worse plant growth under all conditions.”
Hartman said that farmers may not be able to quickly adopt flood-resistant crops, even in areas where flooding is common. Breeders need to invest in producing flood resistant varieties that can be sold to move flood resistance from the lab to the farm. However, Hartman said he hasn’t yet seen that plant breeders are very interested in flood resistance as a trait, favoring instead traits that lead to bigger fruits or higher yields.
While it’s profitable to sell plants that are bred for higher yield, one natural disaster can easily wipe that yield away. As climate change makes weather patterns more unpredictable, such natural disasters are becoming more common, according to a 2021 report by the United Nations’ Food and Agriculture Organization. Hartman suggested that it might be a good idea to invest in traits that improve crop resilience to extreme weather conditions. If farmer and breeder demand is there, though, Hartman thinks getting flood-resistant crops into the ground will happen “very fast.”
Hartman hopes that Hartman’s research will help farmers conserve their crops, increasing food security. “Sustainability is not only about growing more crops with less inputs. I believe that the best way to be sustainable is [to prevent] losing your yields,” he said.
Source: Inside Climate News