The Mississippi Delta is a physiographic region with nearly-level, fertile soils and a climate conducive to intensive row crop production (primarily cotton, soybeans, and rice). However, the long growing season with hot, humid conditions enhances weed growth and insect infestation. Because of the level topography and high annual rainfall, numerous streams, wetlands, and lakes are present. Many of the lakes are what are known as "oxbow lakes" because of their shape. Oxbow lakes are remnants of meandering floodplain rivers which have been cut off and physically isolated from their respective main river channels. These lakes typically capture only small relic drainages. Isolation results in physical and chemical changes in the lake basin and in the floral/faunal assemblages present at the time of separation. Over time, allochthonous (introduced from elsewhere) organic materials are processed and energetically depleted, resulting in the lakes becoming less heterotrophic and more autotrophic. If suspended sediment concentrations are low enough to provide suitable light penetration, isolated oxbow lakes provide conditions conducive to photosynthesis, primarily via phytoplankton, and may support a sustainable sport fishery. However, current agricultural practices on land surrounding these oxbow lakes usually result in high lake turbidity due to fine sediment transport in runoff. Increased turbidity reduces light penetration, which causes inhibition of photosynthesis and loss of productivity. In addition, runoff may transport pesticides and nutrients causing further reductions in lake water quality. Consequently, many Delta oxbow lakes, long known for their fish productivity and recreational value, have become unattractive.

Development of region-specific alternative farming systems (composed of combinations of selected BMPs) is crucial to protecting surface and ground water resources and improving ecological/environmental quality. In particular, this research is critical to the ecological and environmental quality of the entire Mississippi Delta. Research is needed on the alluvial soils of this region because the significance of agrichemical percolation (leaching) to relatively shallow water tables which are hydraulically connected to nearby lakes and rivers is poorly understood. The effectiveness of adjacent riparian zones to trap sediment and to trap and process agrichemicals in runoff is also poorly defined. Essentially nothing is known about the ability of the Delta lakes to recover productivity and/or to sustain an appropriate sport fishery after sediment and agrichemical inputs are permanently reduced.

The potential benefits from conducting this research include: 1) an increased knowledge of how the various physical, chemical, and biological properties of soils affect water and agrichemical movement, 2) the development of improved agrichemical transport models that allow for management, edaphic (inherent in the soil), and environmental variables, 3) new knowledge of agrichemical filter/processing system design and effectiveness, 4) improvements in crop residue and agrichemical management, 5) a reduction in agrichemical application with a concomitant reduction in sediment as well as surface and subsurface agrichemical transport, and 6) ecologically healthy lakes and streams with sustainable sport fisheries.