Mississippi Management System Evaluation Area

Greenwood sites
Jun 1997

Major objectives of the project are:

• Develop alternative/innovative farming systems for improved water quality/ecology in the Mississippi Delta.

• Increase the knowledge to design/evaluate economical environmentally-sound Best Management Practices (BMPs) as components of farming systems.

• Assess the effects of these agricultural activities on surface and shallow ground water quality.

• Increase awareness and adoption by farmers/landowners of alternative farming systems to reduce adverse agricultural impacts on water resources and ecological processes.

Project Design

The project design involves a hierarchy of BMPs in three research watersheds. One watershed, Thighman, serves as a control with no BMPs. A second watershed, Beasley, is receiving nominal (only structural practices) BMPs such as slotted board risers, slotted pipes, grass filter strips, and riparian zones. A third watershed, Deep Hollow, has intense BMPs effort (structural and cultural practices) to include no-till cotton/soybeans with winter cover crop, hooded pesticide sprayers with weed sensor technology, slotted board risers, slotted pipes, grass filter strips, and riparian zones.

The primary crops are cotton and soybeans. The project will assess the ability of Delta riparian zones to assimilate and transform agrichemicals. Success of the project will be demonstrated by reduced sediment and agrichemical transport in runoff, improved water quality/ecology, sustained high crop yields, and enhanced, sustainable fisheries in adjacent water bodies.

The project is located in Sunflower and Leflore Counties in west-central Mississippi. Each of these watersheds is a "closed system" with drainage into "oxbow" lakes. The oxbow lakes in this study range in size from 20 to 40 acres, and the watersheds range in size from 400 to 1900 acres.

Project Description

The premise is that economically feasible BMPs will reduce suspended sediments and agrichemicals leaving the watersheds and entering the oxbow lakes, resulting in improvements in lake water quality and ecology including primary productivity. After implementation of BMPs, all lakes were renovated using rotenone and restocked with largemouth bass and bluegill. Enhanced primary productivity in the treatment lakes is expected to support sustainable sports fisheries. Lake water quality evaluations include measurements of dissolved oxygen, pH, temperature, conductivity, suspended, dissolved and total solids, Secchi visibility, nutrients and chlorophyll. Lake water and bottom sediments are being analyzed for selected pesticides/metals and bioassayed for toxicity.

Surface runoff and shallow ground water are being collected and measured for sediments, nutrients, and pesticides so that contaminant reduction by each BMP or combination of BMPs can be determined.

Macroinvertebrate communities are being characterized and evaluated. This information, coupled with fisheries data (growth rates, condition factors, length-frequency distributions, other stock assessment measures) will be used to assess the ecological health of the oxbow lakes.

Specific research efforts

• Role of soil cracks in agrichemical transport.
• Monitoring selected indicator organisms in the lake ecosystems for pesticide residues.
• Evaluation of BMP effects on the watershed soil properties as related to herbicide sorption and dissipation.
• Pioneering weed control technology (weed sensors).
• Evaluating ARS-developed water quality models for their applicability to the Mississippi Delta.
• Use of precision weather forecasting for timing agrichemical applications.
• Assessment of socioeconomic factors related to farmer acceptance/adoption of alternative farming practices.
• Development of new immunoassays for cotton pesticides.

Project accomplishments

All BMPs have been implemented. Nine surface runoff as well as 20 shallow ground water sampling sites were installed. Each lake has been equipped with water quality sensors and samplers. Installation of similar equipment in the riparian zones is now underway. Prior to treatment with rotenone, all lakes were sampled for the variety and quantity of fisheries.

Weed sensor technology, has dramatically reduced the amount of herbicide needed for weed control in cotton and soybeans.

The lakes were successfully treated with rotenone, which unexpectedly provided a 90 percent improvement in lake water visibility. This had an impact on State policy toward lake restoration.

Several water quality field days were held to explain project goals and successes to farmers, landowners, and officials of cooperating agencies.

Partners/Cooperators/Supporters

Mississippi State University (MSU), University of Mississippi (UM), Mississippi Department of Environmental Quality (MDEQ), USDA-Natural Resources Conservation Service (NRCS), USDA-Farm Services Agency (FSA), Yazoo Mississippi Delta Joint Water Management District (YMD), Delta Council, Mississippi Farm Bureau Federation, U.S. Fish and Wildlife Service (USFWS), Mississippi Department of Wildlife, Fisheries, and Parks (MDWFP), Delta Wildlife Foundation (DWF), USDA-Animal Damage Control, Mississippi Soil & Water Conservation Commission

ARS: John Schreiber (601) 232-2925 schreibe@gis.sedlab.olemiss.edu
USGS: Richard Rebich (601) 965-4600 rarebich@usgs.gov
MSU: Jonathan Pote (601) 325-7355 pote@engr.msstate.edu
NRCS: Lon Strong (601) 965-5159 ls@unix.ms.nrcs.usda.gov