Turning the Prairie, Iowa's Soil and the Plow

Stand in a cornfield in July and you will understand what drew settlers here in the first place. The soil. Iowa sits on some of the deepest, most fertile topsoil on Earth, black and loamy, built over twelve thousand years by the decomposition of tallgrass prairie roots that went six feet into the ground. Glaciers had smoothed the landscape into gentle rolls and filled the depressions with rich sediment. The result was a kind of agricultural lottery ticket unlike anything European-descended farmers had ever seen.

The problem was breaking it. Eastern prairie sod was a dense, matted tangle of roots that shattered wooden plows and bent iron ones. The standard plow had been designed for the lighter, rockier soils of New England and the mid-Atlantic, and it simply could not cut the tallgrass. Settlers who arrived in Iowa in the eighteen thirties and forties spent their first seasons struggling just to open the ground.

The invention that changed everything came from a blacksmith named John Deere, working in Grand Detour, Illinois, in eighteen thirty-seven. Deere fashioned a plow blade from a broken saw blade, using high-polished steel rather than cast iron. The prairie sod, instead of sticking, slid off the blade as the plow cut through. The self-scouring steel plow was not merely an improvement, it was the key that unlocked the interior of the continent. Deere moved his operation to Moline, Illinois, and by the eighteen fifties was selling thousands of plows a year into the Iowa market.

What followed was one of the fastest conversions of landscape in human history. In a single generation, the tallgrass prairie, which had covered most of Iowa, was almost entirely plowed under. Less than one percent of Iowa's native prairie survives today. What replaced it was not wilderness but a kind of engineered fertility, one of the most productive agricultural systems the world has ever known.