By Esther Ngumbi
Tropical Storm Debby has resulted in record-setting rain and flooding events across several States, including Florida, South Carolina, North Carolina and parts of Georgia and left a trail of damage including leaving Florida crops flooded.
Record-breaking rain, flooding events, and other weather impacts people and our ability to grow crops successfully, including wheat, soybeans, maize, and vegetable crops such as tomatoes, which we depend on to meet human food security and nutrition needs.
In the US Midwest, for example, flooding events of 2019 resulted in economic impacts exceeding 6-8 billion USD. In 2023, weather-related disasters resulted in over $21 billion in crop losses. On the African continent, a recent study found that record-breaking rainfall and flooding events contributed to food insecurity.
Predictably, like humans, plants, including maize, soybeans, and tomatoes, are sensitive to flooding. I have seen firsthand the detrimental impacts flooding has on crops such as maize and tomato as a child growing up on a farm in Kenya and today as a University Professor and a researcher at the University of Illinois Urbana Champaign working on a flooding field study that the United States Department of Agriculture funds.
During flooding, plant growth and development are impacted by the deprivation of oxygen, an essential and indispensable element that powers all critical below-and-aboveground plant life-sustaining metabolic and physiological processes, including respiration and photosynthesis.
Ultimately, depending on several factors, including crop genetics, soil and agricultural management practices, temperatures, and crop stage, when flooding happens, plant development and growth are impacted with consequences for yield crop supply and food nutrition and security.
There is an urgent need to understand flooding's impacts on agriculturally relevant crops. Importantly, actionable plans and strategies must be implemented to strengthen crops' resilience to record-breaking events. What can then be done?
To implement actionable strategies against flooding and its detrimental impacts on plants, federal funding agencies, including the United States Department of Agriculture and the National Science Foundation, must invest in flooding research.
First, we must understand the short and long-term impacts of flooding on all crops. How do diverse crop varieties grown today across different environments respond to flooding? Such research would be instrumental in picking out flooding-resistant varieties and unpacking the characteristics and traits, including crop genetics, that underpin flooding resilience.
Such intelligence would then be used to breed climate-resilient crop varieties that can tolerate flooding and thrive under other climate-associated stressors now and into the future.
Second, we must understand the impacts flooding has on soil health, soil biology, and below-ground microorganisms that underpin plants and soil health. Healthy soil is a dynamic matrix that houses microorganisms, including bacteria and fungi, that play diverse functions, including nutrient cycling, nitrogen fixation, promoting plant growth, and suppressing disease-causing pathogens.
Emerging research has revealed that during flooding, in response to declining oxygen levels, soil undergoes dramatic changes in its physical, chemical, and biological properties, including soil pH and nutrient concentrations.
Further, research evidence reveals the accumulation of toxic compounds such as manganese and hydrogen sulfide that can harm soil microbial communities. How long these flooding-induced and associated soil changes last and their impacts on beneficial soil microbe communities across different environments remain largely unknown.
In parallel, we need to understand the role that crop and soil management practices touted as regenerative play in mitigating flooding impacts on plants.
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