Nick Fetty | June 14, 2014

Iowa State University agronomy professor Matthew Liebman has been experimenting with crop rotation as a means of reducing waterway-polluting fertilizer usage, according to a recent article in National Geographic.

Liebman used a three- and four-crop rotation – consisting mostly of corn, soy, oats, and alfalfa – across 22 acres. The study concluded that crop rotation not only reduced nitrogen levels – a byproduct of fertilizers that pollute waterways – but also produced higher corn yields. These pollutants contribute to contamination in the Mississippi River which has lead to a virtual organic “dead zone” where the river empties into the Gulf of Mexico.

Iowa’s Des Moines and Raccoon Rivers has seen record high nitrate levels in recent years. Iowa corn farmers produced 2.2 billion bushels across 13.1 million acres in 2013 which is expected to rise to 2.4 billion bushels across 13.6 million acres.