Location: Soil Drainage Research2009 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
Progress at the DARA field research site is described in detail within the AD-421 for Project 3604-13000-008-14S. Water table elevations were recorded in the control structures at the Hoytville experiment site again during this FY. Crop yields were obtained by the research farm crew per instructions. These data have been downloaded and added to the archived data on the Unit’s server. Water table elevations were recorded in the control structures at 8 producer operated paired DWM sites. These farmers have provided input and crop yield records. These data have been downloaded and added to the archived data on the Unit’s server. The infrastructure renovations and upgrades to the 8 plots where this planned study is to be carried out have been completed. Soil electrical conductivity field map obtained from geophysical resistivity surveys have been used to guide compaction measurements using an automated cone penetrometer. A laboratory investigation of mechanisms affecting nitrate mobility in soil continues. Soil samples from across Ohio and elsewhere in the Midwest have been collected for use and are now being tested to assess anion exclusion processes affecting nitrite transport in a wide variety of soils. Progress is the same as described in Subobjective 1a for the DARA field research site. Field testing of the recombinant inbred (RI) population S99-2281 x PI 408105A segregating for flooding tolerance was completed at two locations for two years. The second year testing for Phytophthora root rot disease is being conducted. Identification of the genetic loci associated with flooding tolerance and Phytophthora tolerance is in progress. One hundred thirty transgenic lines containing the anti-senescence gene were evaluated in the greenhouse. A number of these lines remained green and healthy during the late pod-filling stage and produced twice the seed yield of the non-transgenic type. Additional transgenic soybean lines containing flood-tolerant candidate genes have been successfully generated and are now being grown in the greenhouse for seed collection. Measurement and analysis of the water flow/quality both entering and leaving the constructed wetlands continues at the WRSIS sites. Completed fourth year of field sampling of wildlife (fishes, amphibians, and reptiles) and physical habitat (water surface area, water depth, ratio of open water to emergent wetland vegetation) within the three WRSIS wetlands. Laboratory hydraulic conductivity tests and saturated solute transport column experiments have documented the feasibility of several industrial products and byproducts for use as filter materials to remove nutrients and pesticides from drainage waters. The laboratory portion of the project was completed and manuscript preparation for that portion has begun on the findings from that study. The system was installed in a field setting at a golf course in MN.
1. Improved tolerance of soybean to excessive soil moisture. Soybeans are known to be sensitive to flooding stress caused by ponding in low laying areas due to heavy rainfall. Flooding stress ranked second to combined heat and drought stress for economic losses to US agriculture during the 14-year period from 1990 to 2004. Flooding stress initiates early onset of senescence. ARS scientists, in cooperation with University of Missouri scientists, developed transgenic soybean lines containing an anti-senescence gene and evaluated the impact of flooding on these plants in the greenhouse. A number of these lines remained green and healthy during the late pod-filling stage and produced twice the seed yield of non-transgenic plants. The research will lead to the development of soybean cultivars tolerant to flooding and can potentially address the low yield barrier of soybean.
2. Enhancing created wetlands through hydrology manipulation. Amphibians and reptiles are exhibiting worldwide population declines and conservation practices capable of providing benefits for these aquatic animals in agricultural landscapes are much needed. ARS scientists in Columbus, Ohio documented differences in fishes, amphibians, and reptiles between different wetland types created through the installation of the wetland-reservoir-subirrigation system (WRSIS). WRSIS systems include both a shallow water wetland and a deepwater irrigation reservoir. Aquatic communities in both of these wetland types consisted mostly of predatory fish. Predatory fishes are detrimental to amphibians suggesting the ecological benefits of the WRSIS could be improved if the shallow water wetlands were managed primarily as amphibian habitat. ARS scientists used these results to design a new experiment that alters the hydrology within the shallow WRSIS wetlands to decrease fish abundance and increase amphibian abundance. This research will enable state/federal agencies and non-government organizations information to increase the ecological benefits of created agricultural wetlands by providing needed information to guide the creation and management of created wetlands.
3. Laboratory feasibility testing of sulfur modified iron for use as a filter material to remove contaminants from drainage waters. Filter treatment systems can potentially remove nutrients and pesticides from water discharged by subsurface drainage systems in both large and small scale agricultural settings. The success of these treatment systems will depend on finding economic filter materials that are capable of effectively and efficiently removing nutrients and/or pesticides. Batch tests indicated that sulfur modified iron, a relatively new industrial product, may have potential as a filter material employed for agricultural water treatment. Laboratory hydraulic conductivity tests and saturated solute transport column experiments were conducted to better document the feasibility of using sulfur modified iron as an agricultural water treatment filter material. These results show that sulfur modified iron alone is permeable enough to allow a sufficient water flow and it is effective/efficient in removing nitrate and phosphate from water. Sulfur modified iron when combined in series with another filter material, such as zero valent iron or activated carbon, can also remove the pesticide, atrazine, from water. Consequently, sulfur modified iron used alone or in combination with other filter materials may in the future prove valuable for reducing the adverse environmental impacts associated with agricultural subsurface drainage practices.