News Release Distributed 06/05/14
BATON ROUGE, La. – Nitrogen and phosphorus can help farmers improve yields, but when these nutrients make their way into streams and rivers, they can also contribute to a low-oxygen, or hypoxic, zone in the Gulf of Mexico. To help reduce this type of pollution, the LSU AgCenter and 11 other land-grant universities recently joined the Environmental Protection Agency’s Mississippi River/Gulf of Mexico Watershed Task Force.
The task force, which was established in 1997, consists of five federal agencies and the environmental and agricultural agencies of 12 states. Although land-grant universities in the Mississippi River drainage basin have long been doing research on soil conservation, nutrient management and water quality, they were never included as formal members of the task force until now, said Rogers Leonard, LSU AgCenter associate vice chancellor for plant and soil science programs.
“This is the value of U.S. land-grant universities to the task force,” said Bill Richardson, LSU vice president for agriculture. “Our scientists have a history of success in generating research needed for technology and science-based recommendations for environmental sustainability.”
The agreement will make collaboration among participating agencies much easier. It also provides an opportunity to incorporate universities’ research into the task force’s recommendations, which strive to manage nutrient transport while maintaining crop productivity and food security, Leonard said.
“The advantage of using this multistate approach is being able to look at the hypoxia problem from a macro watershed level,” said Brian LeBlanc, LSU AgCenter and Sea Grant water quality specialist.
Several states border the Mississippi River, meaning pollution from each of them can eventually reach the Gulf of Mexico and feed the hypoxic zone.
Hypoxic waters have low oxygen levels, decreasing the amount of marine life they can sustain, LeBlanc said. In the Gulf of Mexico’s case, the condition is associated with excess nutrients from farms and animal waste. These products enter the river drainage system and flow into the Gulf, fueling rapid algae growth.
“You get this giant bloom of very happy algae populations, and they reach a point where they die,” LeBlanc said. “When they die, they decompose, and that process utilizes oxygen.”
While algae are essential to the Gulf, they have reached “too much of a good thing” status in recent decades, LeBlanc said. Levees built in the 1920s channeled the Mississippi River and increased the concentration of nutrients in the river.
“You didn’t have the natural flow of the river across landscapes during flood time, when sediments and nutrients would get absorbed by other things,” LeBlanc said. “As farming techniques got more aggressive and better, the combination of the two started forcing a lot of runoff straight into the river.”
According to the Environmental Protection Agency, the hypoxic zone measured about 5,800 square miles in 2013. However, this is a moving target, Leonard said — the size of the zone changes each year depending on environmental and physical factors that influence how much nutrient content reaches the Gulf.
The task force’s action plan calls for limiting the zone to about 2,000 square miles, which would require up to a 45 percent reduction in the nitrogen and phosphorus load that flows down the Mississippi River. However, that doesn’t necessarily equate to a 45 percent reduction of fertilizers used on farms, Leonard said.
Still, improving efficiency is always important in agriculture. LeBlanc said there is a number of ways farmers can reduce runoff that contributes to the hypoxic zone. Many of these strategies are taught in the Master Farmer Program, which is a collaborative effort of the AgCenter and state and federal agencies that encourages sustainable management practices.
Depending on which crops a farmer produces, pollution reduction strategies can include creating grass buffers between crops and waterways, fencing livestock away from streams and using no-till farming methods to reduce soil erosion, LeBlanc said. These practices not only decrease runoff and pollution, but can also help farmers save money and be more efficient.
Nutrient management on farms and in watersheds is just one of many significant current and future challenges that need to be addressed, Leonard said. A rapidly growing world population means food production must increase, he said, so it is important to take a balanced approach toward solving both environmental and agricultural issues.