NCR-195, Mississippi River Watershed Nutrient Sources and Control

Background and Justification

Highlights of Committee Activities and Accomplishments

States and Active Participants

Publications and Resources

Hypoxia Links

The NCR-195 committee serves as an information transfer link concerning nutrient sources and controls throughout the Mississippi watershed, although its activities are concentrated in the upper reaches of the watershed. The committee is composed of university and federal (USGS, USDA, EPA, NOAA) scientists, state extension personnel, and representatives of the farm owner and operator, crop consulting, and fertilizer industry communities.

NCR-195 is a multi-state research committee of the North Central Regional Association of Agricultural Experiment Station Directors (link to

Committee Objectives

1. Serve as a central information source and coordinating body for agricultural issues relating to nutrient loading from the Mississippi River to the Gulf of Mexico.

2. Coordinate, promote and facilitate multi-state research, educational and extension programs to help individual states deal with their impacts of surface water loading from nutrients.

3. Continuously review current knowledge and technologies with respect to their impact on nutrient management for water quality.

Minutes of Past Meetings

  • November, 1999
  • November, 2000

Meeting Announcements

The 2001 meeting will be held in St. Louis, probably in November 2001. Tom Franti is responsible for organizing.

Background and justification

Sufficient information has been obtained to verify that the shallow inner shelf of the Gulf of Mexico is undergoing accelerated eutrophication as a result of nutrient (nitrogen and possibly phosphorus) input from the Mississippi River. This great river drains over 44% of the area of the contiguous United States, and the watershed encompasses the most productive agricultural area in the World. The net effect of nutrient inputs is the rapid depletion of oxygen in the bottom waters during the summer months. This condition is known technically as hypoxia when the oxygen level declines below 2 mg/liter and as anoxia when oxygen disappears altogether. Hypoxia and anoxia results in death of bottom dwelling nonmotile organisms. Motile organisms such as fish and shrimp migrate to more hospitable areas. Hypoxic conditions also cause a shift in the aquatic population mix and as a result, the general structure of the aquatic community waters. Over 7,000 square miles of the Gulf of Mexico are affected by hypoxia each year.

While overabundance of P is generally regarded as the chief cause of surface water quality problems in fresh waters, marine estuarine systems like the Gulf are usually N-limited. . Silica also is important. Research indicates that the lowering of Si output because of watershed changes over the last century has changed the abundance of various phytoplankton in the Gulf. Introduction of N stimulates marine phytoplankton production. The detritus settles and undergoes decomposition increasing the oxygen demand in the system. Oxygen diffusion downward to replace oxygen used in decomposition is limited by formation of a salinity barrier (halocline) caused by addition of fresh water from the Mississippi River that is not completely mixed with the saline water of the Gulf.

While many of the factors, contributing to hypoxia in the Gulf of Mexico have not been identified, much of the blame has been relegated to agriculture's contribution to non-point source pollution in the Mississippi River basin. Erosion, surface-runoff, and tile-drainage from agricultural fields contribute a major portion of the estimated 1.5 million metric tons of N per year which, on average, have entered the Gulf of Mexico from the Mississippi River since 1960. Analysis of USGS data indicate a doubling of N flowing from the watershed from 1960-1980 and little increase in the past two decades. The primary sources of nitrogen are the Corn Belt states; smaller amounts come from the Missouri and Ohio River watersheds. Lowering the contribution of nutrients from these watersheds will not be an easy task, especially in watersheds where animal manure is the major N source. It will require coordinated research and information transfer programs throughout the north central region, and must involve the farm community as well as the fertilizer input industry.

Highlights of Committee Activities and Accomplishments

The committee was initially constituted as an NCT committee (NCT-167). An organizational meeting was held at Kansas City in November 1996. Several white papers covering various aspects of N management and research needs in the upper Midwest were discussed. These papers were presented at the workshop held in Anaheim in October of 1997. The committee elected Dennis Keeney (IA) as chair and Chuck Rice (KS) as secretary. Dale Vanderholm (NE) was assigned as the administrative advisor.

The second official meeting of NCT-167 was held at Baton Rouge, LA with several Gulf Coast scientists and administrators. Dr. Bill Branch (Louisiana CES organized the meeting. The committee heard from leading oceanographers and fishery people involved with Gulf hypoxia. This meeting increased understanding of the issues in common between the Midwest and the Gulf Coast states. Dr. Branch is now a member of NCT167 and is providing a key linkage of the committee with on-going programs in the Gulf area.

At the March 1997 meeting it was decided that an application for Fund for Rural America Center planning funds be prepared to develop an Agro-Oceanic Flux Center proposal. The planning grant proposal was successful and a proposal for a Center based at Iowa State (John Downing, IA, and PI) is being prepared. This Center would involve current NCT-167 members. Dr. Jim Schepers (USDA-ARS, NE) suggested the committee apply for funds from OECD to put on a workshop on Hypoxia at the October meeting of the American Society of Agronomy. Dennis Keeney obtained OECD funds and an extremely successful workshop was held. Experts from around the world discussed various aspects of estuarine eutrophication. This was the first workshop on hypoxia held by the American Society of Agronomy. An NCT-167 committee meeting was also held at the conclusion of the workshop. It was decided during this meeting to apply for NCRE status. The committee felt the move to a NCRE committee is justified given the urgency of the issue and the high level of activity of the committee with various user groups.

States and Active Participants:

North Central Region

State / University participants / Other participants
Illinois / Robert Hoeft (E), University of Illinois-Urbana
Indiana / Ronald Turco (R) Jane Frankenberger (E), Purdue University
Iowa / Jim Baker ( R) Dennis Keeney (R) John Downing (R) , Gerry Miller, (E), Iowa State University / Michael Burkhart USDA-ARS Tilth Lab
Kansas / Charles Rice (R ) Dan Devlin (R), Kansas State University
Minnesota / Jim Anderson (E) Gyles Randall, (E/R), University of Minnesota / Robert Dowdy, USDA-ARS
Missouri / Eugene Alberts (E) Peter Scharf (R) Stephen Jones (R), University of Missouri
Nebraska / Bob Volk (R) Tom Franti , ( R), University of Nebraska / Jim Schepers, USDA-ARS
Ohio / Larry Brown (E), Ohio State University / Norman Fausey, USDA-ARS
Wisconsin / Keith Kelling (E/R), University of Wisconsin

Other Regions

Louisiana William Branch, (E), Louisiana State Univ. Baton Rouge

Other Participants

William Battaglin, USGS, Denver

Maurice Horton, USDA-CREES, Washington DC

Terry Francl, American Farm Bureau, Illinois

Don Casey, The Fertilizer Institute Washington DC

Publications and Resources

(This will be what members send in.)

Hypoxia Links (suggested by members)

  • USGS site on nutrient loads and sources in relation to Gulf hypoxia. (sent by Don Goolsby)
  • NOAA site: