We often disdain soil, also known as dirt. We sweep it off our front porches and back decks and wipe it off our shoes before entering our houses. However, soil is much more important than we realize. When soil degrades, agriculture suffers. “Healthy soil is the foundation of productive, sustainable agriculture,” according to the U.S. Department of Agriculture (USDA).
At an international conference in Morocco in July, UNESCO warned that 90 percent of the planet’s land surface could be degraded by 2050. Seventy-five percent of the world’s soils are degraded, which impacts 3.2 billion of the world’s eight billion people. By 2050, this could rise to 90 percent.
Soil degradation is costly. Researchers analyzed various scenario-based models of fertilizer use and maize production. They found that about one-third of annual fertilizer use in the U.S. for maize is to compensate for the loss of soil fertility caused by erosion and organic matter loss. That costs over $500 billion annually in extra fertilizer costs. A report by the Rockefeller Foundation found that soil erosion costs the U.S. around $67 billion per year.
Soil Erosion in the U.S.
The U.S. has a storied history of soil erosion. That history is called the Dust Bowl, which occurred in the 1930s when the grassland areas of the country experienced severe drought. Until the First World War, the area mainly had livestock. During that time, farmers planted millions of acres of wheat. Poor land management and over-cultivation combined with drought exposed the area’s topsoil. With native grasses plowed and removed to make way for wheat, the topsoil blew in the wind. When drought ended in the early 40s, so did the Dust Bowl.
A wheat farmer from Kansas named Lawrence Svobida wrote about his experiences during the Dust Bowl in his memoir, “Farming the Dust Bowl.” Wind causes dust and dirt to blow, and “sometimes it was so thick that it completely hid the sun,” he wrote. The visibility ranged from 50 feet to nothing. Even with goggles, people’s eyes would fill with dirt. During a dust storm,
birds flew “in terror…and only those that are strong of wing may escape.” Many birds died, along with jackrabbits who suffocated.
Another Dust Bowl?
Is the U.S. headed for another dust bowl in the nation’s grasslands? Studies indicate it could happen. A 2022 research study analyzed high-resolution topographic studies of areas in the Midwest to predict soil erosion from the advent of farming until now. Researchers estimated the median historical erosion rate to be double the rate tolerable by the U.S. Department of Agriculture (USDA). “Our findings indicate that further implementation of conservation practices is needed to reduce the high centennial-averaged soil erosion rates that we measure to sustainable levels,” they concluded.
According to a 2021 study, topsoil has eroded from around one-third of the midwestern U.S. Corn belt. Researchers estimated that topsoil erosion decreases crop yields by over two percent, costing farmers billions of dollars. Researchers from the University of Massachusetts Amherst analyzed soil erosion over the 160 years since Europeans first settled in the Midwest, bringing agriculture to the area. The soil eroded two millimeters per year, on average. That is almost double the rate the USDA considers sustainable. Plowing is the driver, researchers concluded.
Climate change is another driver behind topsoil erosion. Simulations and empirical models indicate that a Dust Bowl type of drought would have “unprecedented challenges,” according to a 2016 study. A 2020 study found that climate change and land use already altered the U.S. Great Plains. Researchers concluded that the results “suggest increased dust due to agricultural expansion is negatively influencing human health and visibility in the Great Plains…foreshadow a future where desertification becomes an increasing risk.”
