NCERA207: Drainage design and management practices to improve water quality
- Duration:
- October 01, 2004 to September 30, 2009
- Administrative Advisor(s):
-
Rameshwar Kanwar
(IOW)
- Research
- NIFA Reps:
-
Mary Ann Rozum
Statement of Issue(s) and Justification:
Excess nitrate (NO3) in drinking water can be toxic to humans1, requiring costly treatment of water for human consumption. Excess N in estuaries and coastal waters enhances algal growth2 and is implicated in the formation of a hypoxic zone in the Gulf of Mexico3. The principal sources of nitrogen to the Mississippi river are the agricultural basins within the Midwest corn-belt4, 5. Major source of NO3 in surface waters within these basins is artificial subsurface drainage6, 7. While much of this loss of N is commonly attributed to overuse of commercial N fertilizer, studies by Keeney and DeLuca8 and Willrich9 illustrate that considerable N loss was occurring before the wide spread use of inorganic fertilizers and that N leaching loss is more of a result of crop production per se (drainage, tillage, etc.) than of irresponsible fertilizer use. Within the twelve state North Central Region, there are >41,000,000 acres of drained cropland under production (Appendix 1), with up to 50% of all land under production being drained in some states10. These lands are some of the most productive in the world, but only if adequate drainage is provided.In addition to the role subsurface drainage plays in transporting nitrate to surface waters, there is continuing concern for its role in transporting pesticides to streams and lakes. Subsurface drainage may also play a central role in a number of emerging issues. These include the transport of pathogens and pharmaceuticals to surface waters as a result of manure application to drained land exhibiting preferential flow behavior. Drainage may also play a significant role in the transport of phosphorus to surface waters and often exceeds levels suitable for fishable, drinkable, and swimmable rivers and lakes. There is growing evidence that subsurface drainage waters can also exceed the P concentration levels recommended by EPA for surface waters.
In a recent review by Dinnes et al.11, several approaches were proposed for reducing the impact of drained agricultural lands on surface water quality. These included the use of alternative crop rotations and cover crops, improvements in the timing and rate of fertilizer application, and redesign and management of drainage systems to reduce the contribution of nitrate mass to surface waters. Currently, researchers across the North Central Region are investigating these and other approaches for reducing nutrient and other contaminant losses from drained croplands. While this research has shown promising results, there is little coordination or interaction amongst the different state researchers. Thus, there is little exchange of new ideas amongst researchers and as a result little synergy that such exchange could produce in developing new approaches to improve water quality. Lack of coordinated evaluation of alternative management practices and drainage designs across the Region hinders attempts to identify effective practices for reducing contamination of surface waters within the different states. A coordinated research program, focused on the unique characteristics of subsurface drained lands, would be of considerable benefit to farmers, the drainage industry, and the various state departments of agriculture and natural resources who will be charged with identifying and implementing management and infrastructure changes to reduce surface water contamination. This coordinated research effort will also be of benefit to the Agricultural Drainage Management Task Force within the ARS-NRCS-CSREES Partnership Management Team and the USDA-NRCS who are charged with evaluating the efficacy of alternative drainage designs and management approaches as nutrient control practices.
Objectives
- Evaluate the effectiveness of alternative drainage design and operational practices, to reduce nitrate-N losses from drained agricultural lands.
Research in many of the North Central states is currently underway to develop and test different drainage design and management systems. There is a critical need for researchers from the different states to meet regularly and exchange information about the research and results. Research should be coordinated where possible, so that unnecessary duplication is avoided and the appropriate variables are measured to allow comprehensive comparisons across the corn belt.
- Assess the impact of various soil and crop management practices on reducing nitrate-N loadings to subsurface drains.
Research is being conducted on tile-drained fields, to evaluate different in-field management practices for reduction of nitrate-N losses into tiles, including use of cover crops, fertilizer practices, tillage and rotation, etc. This objective is specifically related to reducing nitrate-N leaching into tile drains, and thus does not overlap significantly with the NC-218 objectives for soil N mineralization and diagnostic criteria for N rates for crops. Discussion of comparative studies conducted in the different soils and climates within the region, are important for understanding and improving management on these drained lands.
- Assess the need for further research in other aspects of water quality from drained agricultural lands, including the emerging issues of pathogens and phosphorus from manure applications.
Although the main emphasis of the committee will be on nitrate-N leaching into tile drains, there are other issues that the committee thinks need to be kept in mind while trying to "solve the N problem." Subsurface drainage usually reduces the losses via surface runoff of sediment, pesticides, and phosphorus, and so management practices designed to reduce nitrate leaching should also evaluate the potential negative impacts on these other components. An emerging area of concern is movement of pathogens, pharmaceuticals, and phosphorus via preferential flow into tile drains in manured fields. The committee will facilitate the exchange of information on these emerging issues and help coordinate new research on these topics.
- Develop drainage guides and other extension materials, and work with state and federal action agencies, to assist in implementation of improved design and management practices for subsurface drainage systems.
The committee will include extension personnel and an NRCS representative, and will coordinate the development of educational materials for drainage design and management for improved water quality. The committee will work with the Agricultural Drainage Management Systems Task Force (ADMSTF) to assess needs for technical bulletins and other educational material. Many of the representatives on the NCR committee are also participating in meetings of the ADMSTF, which will facilitate communication and coordination between the groups.
