Modern Agriculture’s Impact on Nutrient Loading

Overview Modern agricultural practices are very effective at producing high crop yields and increasing overall food security. However, many of these practices have significant environmental externalities that affect human welfare in various ways. Our Healthy Soils for Healthy Waters Initiative focuses on nutrient loading, a widespread and destructive byproduct of intensive modern agriculture. Eutrophication Nitrogen and phosphorus are important nutrients for plant growth and farmers commonly add them to soil to increase crop productivity. Rain easily washes away some of these added nutrients and in the case of the Mississippi River basin, eventually collects in the Mississippi River and flows to the Gulf of Mexico. This warm, nutrient-dense freshwater from the river floats above the cooler, saline water of the Gulf.  The extra nutrients, usually a limiting factor in algal growth, enable excessive phytoplankton growth in the top layer of water. The plankton die and eventually sink to the bottom layer of the gulf, where they decompose and use up the oxygen in the bottom saline layer. Marine life needs oxygen to survive just like we do, so those organisms that are unable to move away from the oxygen-depleted “hypoxic” zone, such as lobsters, crabs, and young fish, die. With the current unstable state of nearly all fish stocks, these die-offs from hypoxic zones are making an already precarious situation even worse. In 2014, the hypoxic zone in the Gulf of Mexico measured in at 5,052 square miles. The zone fluctuates in size from year to year, but this is due to varying weather patterns, not any real overall reduction in pollution (Maryland DNR, 2005). See the Greenleaf Advisors article:...