What the ‘Quiet Crisis’ of Soil Loss Does to Crop Yields, Greenhouse Gases
May 2, 2018 At the west end of The Ohio State University’s Columbus campus, within eyeshot of Ohio Stadium and the Columbus city skyline, passed by thousands of commuters daily, lies a soil study site about the size of a basketball court that could help change the planet, or at least about 4 billion acres of it, according to an article on OSU’s College of Food, Agricultural, and Environmental Sciences website.
In a recent study done at the site, a team led by Ohio State soil scientist Rattan Lal found that topsoil erosion, in addition to reducing crop productivity, causes the release of greenhouse gases.
However, the study also suggests that topsoil can be rebuilt, and the harmful effects of its loss reversed, faster than had been previously thought.
“The general statement is that forming 1 inch of topsoil may take thousands of years,” said Lal, who is Distinguished University Professor of Soil Science in the College of Food, Agricultural, and Environmental Sciences (CFAES). But adding organic matter such as compost to eroded land could shorten that time significantly, he said.
Lal also is director of the Carbon Management and Sequestration Center in CFAES’s School of Environment and Natural Resources.
The study appeared recently in Scientific Reports, which is published by Nature.
Lower crop productivity affects farmers’ profitability, and in developing nations, can lead to food insecurity and hunger.
Rising greenhouse gas levels, meanwhile, are causing climate change, and with it, problems such as weather extremes.
In all, topsoil erosion affects slightly more than 4 billion acres of land around the world, Lal said, an area about twice the size of the continental U.S. Water causes about two-thirds of that erosion, wind the other third. The harmful effects include lower crop yields and higher production costs for farmers because topsoil is the richest soil layer.
Topsoil erosion also can carry sediments, pesticides, and nutrients from fertilizer and manure into lakes and streams. Phosphorus, a cause of the harmful algal blooms plaguing Lake Erie and other water bodies, can be one of those nutrients.
But erosion’s impacts usually appear slowly. Erosion-caused yield losses, for example, “may not be recognized until crop production is no longer economically viable,” the authors wrote in the study.
It’s for that reason, Lal said, that “erosion is often called ‘the quiet crisis.’”
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