The oxygen depleted, or "hypoxic" area of the Gulf, in July covered an area the size of New Jersey, with a noticeable impact on animal populations, especially those that cannot escape the area such as clams and worms.  NOAA

Corn and soybean production is the leading source of nitrogen in the Mississippi River, contributing about half of what finds its way to the Gulf, according to a USGS modeling effort.

Phosphorus comes disproportionately from areas with intensive livestock production and pasture, which contribute about 37% of the phosphorus reaching the Gulf of Mexico.

Corn and soybeans contribute about 25%. USGS

Illinois contributes approximately 17% of the nitrogen and 13% of the phosphorus reaching the Gulf, which is more than any other state, according to the USGS analysis.

The phosphorus load during April through June was the largest on record since 1979 while the nitrogen load was the fourth largest on record. The amount of water flowing down the river was the third largest since 1979. USGS

To reduce water quality impacts from agricultural production, the USDA funds programs such as the Conservation Reserve Program and the Wetland Reserve Program.

Back in 1997, relevant state, federal and tribal agencies formed the Mississippi River/Gulf of Mexico Watershed Nutrient Task Force to promote and coordinate research, education and conservation efforts related to hypoxia in the Gulf of Mexico. EPA

In 2001 the Task Force approved an “Action Plan” to reduce by 30% nitrogen reaching the Gulf, hopefully shrinking the hypoxic area to 1930 square miles by 2015. EPA

In 2007 an assessment of the Action Plan found that nitrogen delivery to the Gulf between 2001 and 2005 had decreased by 21%, but hypoxia had increased.  EPA

Other research has indicated that phosphorus has played more of a role in the formation of hypoxia than had been recognized in the 2001 Action Plan.  EPA

Phosphorus movement to the Gulf between 2001 and 2005 was 12% greater than during 1980-96. The reason for the increase in  phosphorus movement is unknown since the efficiency of both nitrogen and phosphorus use in crop production improved significantly in recent years. EPA

The Task Force has approved a new Action Plan in 2008 which calls for a 45% reduction in nitrogen and phosphorus movement to the Gulf.  EPA

It also indicates that climate change may require even greater reductions, and that achieving the goal by 2015 will be difficult.  EPA

Although fine tuning nutrient use of the existing agricultural system may provide some reduction, it is unlikely to achieve 45%.  The use of cover crops and perennial crops, such as switchgrass for biofuels, have a greater potential to reduce nutrient losses.  EPA

Follow up with a radio interview from Focus 580