Above: Plowing virgin prairie with oxen. Archive photo.
When early settlers ran the first plow through virgin tallgrass prairie, they soon discovered how deep and dense the prairie root system was. New Jersey tea was known as the pest of the plowman or rupture root because its huge taproot would damage plows. Leadplant was called prairie shoestring due to the sharp, snapping sounds made when a plow point tore through its rootlets. A regular plow and a mule could not cut the tough sod, it took a breaking plow and a team of oxen. But break it they did. A good team and a long day of backbreaking labor could plow up one or two acres. Within one generation, early farmers—without modern equipment—plowed 99% of the Iowa prairie into cropland and stopped the cycles of the tallgrass ecosystem. Over thousands of years the prairie had built soil so rich and deep that it has been productive cropland for decades. Iowa owes its productive agricultural economy to prairie soils.
From Mark Muller's "The World Beneath Your Feet: A Closer Look at Soil and Roots," Funded by the Iowa Living Roadway Trust Fund