Gypsum as a soil amendment to enhance water quality by reducing soluble phosphorus concentrations

Excerpt

It is said that lakes are born to die. As soon as a lake basin is formed, either slowly by glacial action as for the Great Lakes or rapidly by the New Madrid earthquake for Reelfoot Lake, Tennessee, in 1811 to 1812 (USGS 2012), it fills with water. It then begins to accumulate sediments and nutrients, including phosphorus (P), that increase productivity. This ultimately results in the lake basin filling with sediments and organic materials. The Maumee River drainage basin (area of 21,050 km² [8,132 mi²]) on the western edge of Lake Erie occurs primarily in Ohio but also includes parts of Indiana and Michigan (figure 1). The basin has high agricultural productivity, with approximately 80% of the land devoted to row crop corn (Zea mays L.) and soybeans (Glycine max [L.] Merr.). The Maumee River drains into the shallow western basin of Lake Erie and contributes most of the sediment and one-third of soluble P that enters Lake Erie.

Runoff from agricultural fields often contains excessive P that impacts water bodies in a process called cultural eutrophication (National Academy of Sciences 1969). Beginning in the 1950s, Lake Erie was strongly affected by cultural eutrophication (Verduin 1969). In the 1960s…