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United States Department of Agriculture

Agricultural Research Service


Location: Soil Drainage Research

2012 Annual Report

1a. Objectives (from AD-416):
The overall project goal focuses on improving subsurface drainage water management systems (DWMS), particularly those employing controlled drainage practices, which will be used throughout the Midwest U.S., to provide both environmental and economic benefits. Accomplishing this goal requires an integrated research program that leads to enhanced controlled drainage operational strategies, improvement of DWMS design, development of flooding tolerant crop cultivars, and innovation in agricultural water treatment technologies. Specific objectives include: 1) Develop a knowledge base that will provide useful insight for improving controlled drainage operational strategies so as to maximize environmental and economic benefits. 2) Collect field data that will offer useful insight on proper DWMS design (particularly for controlled drainage systems), and then conduct a computer modeling investigation to determine the best controlled drainage design criteria and operational strategies that provide environmental and economic benefits. 3) Develop flooding stress tolerant soybean cultivars that are better adapted to Midwest U.S. DWMS wet soil conditions. 4) Develop constructed wetland and other water treatment technologies that can be integrated with DWMS to reduce nutrient and pesticide losses from cropland and turf environments.

1b. Approach (from AD-416):
Conduct plot studies to quantify the subsurface drainage effects of three outlet control structure weir elevations and a scenario in which the outlet control structure weir height is gradually lowered. Conduct producer operated, field scale comparisons between open, unrestricted versus controlled subsurface drainage systems. Determine the effects of controlled drainage versus open, unrestricted drainage on surface runoff. Determine the soil quality effects of controlled drainage verses open, unrestricted drainage. Perform laboratory tests and field investigations to quantify processes affecting nitrate mobility in low permeability Midwest U.S. soils that typically require artificial subsurface drainage. Conduct plot studies to evaluate different subsurface drainage system infrastructure characteristics for the purpose of improving DWMS design criteria. Using data collected from different Midwest U.S. field locations, calibrate and verify computer models capable of simulating DWMS flow, water quality, and crop yield responses. If necessary, modify the computer program used to develop the computer models. Screen soybean cultivars of diverse origins for flooding stress tolerance and employ quantitative trait locus (QTL) mapping on the most promising cultivars in order to locate genes on the genetic linkage map that are responsible for flooding stress tolerance. Develop transgenic soybeans with improved flooding tolerance and then verify their flooding tolerance. For three constructed wetlands, assess present water treatment effectiveness along with vegetation/wildlife function and then evaluate, on the same basis, improvement modifications. Perform laboratory tests to screen novel filter materials for ability to remove nitrate and atrazine from drainage water. If an effective and efficient filter material is isolated in the laboratory, a field pilot test will follow. Evaluate the ability of commercially available filter materials to absorb or bind nutrients and pesticides present in tile drainage water from an urban turf environment.

3. Progress Report:
This is the final report for project 3604-13000-008-00D, which was terminated 12/21/2011 and replaced with 3604-13000-010-00D. Substantial results were realized over the 5 years of the project. A field research facility in northwest Ohio was fully instrumented to compare controlled (restricted) subsurface drainage versus conventional, unrestricted subsurface drainage with respect to differences in crop yield, discharged drainage water quality, drainage water discharge volume, and shallow water table response. Eight on-farm paired sites were established and will be used over the next 5 years to document the hydrologic and crop yield responses to seasonal drainage water management. Data were obtained from replicated runoff plots to determine the effect of controlled subsurface drainage on surface runoff. Soil profile compaction and electrical conductivity data has been tabulated at five field locations for determining soil quality impacts of controlled drainage practices. Laboratory tests have quantified the impact on nitrate mobility in unsaturated soil due to factors that impact the magnitude of the anion exclusion effect. Working with scientists in Vietnam, determined and published that use of the screenhouse test method is cost effective and less seasonally dependent for testing flooding tolerance of soybean germplasm. Then used this method to test 21 soybean germplasm from Southeast Asia and found three lines identified as VND2, Nam Vang, and ATF15-1 with superior flooding tolerance. Transgenic soybean containing the flood tolerance SAG12:IPT transgene were generated by the Agrobacterium-mediated transformation technique. The goal was to identify the seeds that were homozygous for the transgene, produce more seeds from them and test these plants for flooding tolerance. Did not proceed that far with the SAG12:IPT transgenic plants because extensive testing of T3 plants could not identify transgenic plants. The transgene appeared unstable and was eliminated. Additionally, the influence of wetland type, hydrology, and wetland destruction on aquatic communities was examined at the three northwest Ohio WRSIS sites for development of WRSIS wetland design and management criteria based on providing improved habitat for aquatic vertebrates. A laboratory testing program isolated several iron-based filter materials capable of removing nutrients (nitrate/phosphate), pesticides, and trace elements from agricultural waters. Substantial progress was made on investigating the use of various industrial byproducts as filter media. The development and testing of filter systems that permit larger flow rates should be explored.

4. Accomplishments

Review Publications
Smiley, P.C., Allred, B.J. 2011. Differences in aquatic communities between wetlands created by an agricultural water recycling system. Wetlands Ecology and Management. 19:495-505.

Last Modified: 2/23/2016
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