Soil Quality Critical to Help some US Crops Weather Heat Stress from Climate Change

Jul 15, 2022

By Carol Clark

The capacity of soil to hold water will be critical to determine how well farms in some regions of the United States manage the problem of prolonged heat stress due to climate change, a new study suggests. The journal Frontiers in Sustainable Food Systems published the finding, based on analyses of 30 years of data on four major U.S. crops—corn, soybeans, cotton and wheat.

"At the same time that farmers are facing more extreme weather events caused by climate change they are dealing with the growing problem of soil degradation," says Debjani Sihi, first author of the study and assistant professor in Emory University's Department of Environmental Sciences.

Sihi is a biogeochemist who studies environmental and sustainability issues at the nexus of soil, climate, health and policy.

Globally, according to Sihi and her co-authors, 750 million people were undernourished in 2019 due to the effects of climate change, including a decline in food production, hikes in food prices and increased competition for land and water. And the problem of global food security is expected to intensify. World crop yields are projected to decrease by 25% overall within the next 25 years due to climate change, and yet global food production would need to double by 2050 to feed the projected growth in human population.

"Keeping soil healthy is a key component needed to adapt to the climate crisis," Sihi says.

Healthy soil contains microbes that provide the nutrients needed for healthy plants to grow, she explains, while also helping make the plant foods that we eat more nutritious. The presence of these microbes also improves the ability of soil to sequester carbon. The top 30 centimeters of the world's soil contains about twice as much carbon as the entire atmosphere, making soil the second-largest natural carbon sink after oceans, according to the United Nations' Food and Agriculture Organization.

The rise in average temperatures, however, is contributing to declines in soil moisture in some areas, which can impact crop production while also degrading the soil over the long term.