Surf or turf: A shift from feed to food cultivation could reduce nutrient flux to the Gulf of Mexico

The extensive use of nitrogen fertilizer on the central U.S. croplands contributes to nitrogen loading by the Mississippi River and the development of seasonal hypoxia in the Gulf of Mexico. The majority of grains cultivated on central U.S. croplands are used as animal feed, rather than directly as human food. In this study, the IBIS-THMB nitrogen modeling system is used to demonstrate how a shift away from meat production from Mississippi Basin crops could reduce total land and fertilizer demands by over 50%, without any change in total production of human food protein. The change would return nitrate-nitrogen export by the Mississippi River to levels at which the Gulf of Mexico “dead zone” has been small or non-existent. An analysis of future land use scenarios and other mitigation proposals, including the construction of riparian wetlands, indicates that a reduced focus on beef production may need to be a part of nitrogen management policy in the Mississippi Basin.