A new study in the journal Earth’s Future – led by the University of Massachusetts Amherst – shows that agricultural fields in the midwestern US have lost, on average, two millimetres of soil a year since Euro-American settlement approximately 160 years ago. This is nearly double the rate of erosion that the United States Department of Agriculture considers sustainable.
Furthermore, USDA estimates of erosion are between three and eight times lower than the figures reported in the study.
Finally, the study’s authors conclude that ploughing, rather than the work of wind and water, is the major culprit.
“A few years back, my wife and I were at a wedding at a pioneer Norwegian church in Minnesota,” says Isaac Larsen, professor of geosciences at UMass Amherst and one of the paper’s co-authors.
“After the ceremony, I walked over to the edge of the churchyard, which was surrounded by cornfields, and was shocked to see that the surface of the field was a few feet lower than the surface of the never-tilled churchyard. I began to wonder why.” Continue reading