Location: Soil Drainage Research2008 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
1a: Sensors were added to continuously record water table levels in all test plots at the DARA (Defiance Agricultural Research Association) site. Hydrologic, water quality, and yield data were collected at both DARA and Hoytville plots year round in response to rainfall inputs. 1b: Eight farmer cooperators in Ohio have provided paired fields where the environmental/economic differences between controlled drainage and conventional, unrestricted drainage can be evaluated. Hydraulic control structures, sensors, and data loggers are now in place at all of these sites. 1c: Site infrastructure changes needed for surface water runoff tests have now been completed. 1d: To determine sampling locations for soil quality research, near-surface geophysical resistivity surveys integrated with GPS were conducted to obtain topographic and soil electrical conductivity maps at 7 sites. 1e: A laboratory investigation was completed that quantified the impacts on soil nitrate mobility due to the type of dissolved cation present. Soil samples from across Ohio and elsewhere in the Midwest have been collected for use to assess anion exclusion processes affecting nitrite transport in a wide variety of soils. 2a: Sensors were added to continuously record water table levels in all plots. Baseline characterization of individual plot hydrologic response to rainfall was continued year round. 2b: Work on this subobjective is not scheduled to begin until the third year of the overall research project. 3a: Field testing and genotyping of a recombinant inbred population segregating for flooding tolerance was completed. Two manuscripts from this research have been submitted to scientific journals. 3b: Eight SAG12:ipt transgenic soybean lines have been developed and tested for flooding tolerance. Four additional constructs containing flood-tolerant candidate genes have been generated for transformation into soybean. 4a: Measurement and analysis of the water flow and water quality both entering and leaving the constructed wetlands continues at the three WRSIS (Wetland Reservoir Subirrigation System) sites. The third year of sampling for fishes, amphibians, reptiles, and habitat data were completed for the WRSIS wetlands and reservoirs. Preliminary analyses indicate the predominance of predatory fishes within the WRSIS wetlands that could be potentially detrimental to amphibians. 4b: A total of 55 filter materials have been screened to date. Further batch tests were conducted on five of the most promising filter materials to gain additional insight on their effectiveness/efficiency in removing nutrients/pesticides from agricultural drainage waters. 4c: Two years of data has been collected at the field site and is currently being analyzed. Likewise, laboratory data has been collected at the 10, 20, and 30 gallon per minute peak flow rates and is currently being analyzed. Initial results indicate that the end of line filters have the ability to significantly reduce concentrations and loadings of both nutrients and pesticides. The project’s 12 research subobjectives support NP 201 (now NP 211) Problem Area #3, Products #1 and #2, and Problem Area #6, Products #4 and #6.
1. Testing of Filter Materials for Removal of Nutrients and Pesticides from Agricultural 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. Initial batch test screening of 55 industrial products/byproducts found five that exhibited promise as filter materials for removing nitrate, phosphate, and atrazine from drainage waters. Additional batch tests were conducted to further delineate the effectiveness and efficiency of these five materials (activated carbon, high carbon fly ash, iron sulfide, sulfur modified iron, and surfactant modified zeolite), and the results indicate that all five filter materials removed significant amounts of nitrate, phosphate, and atrazine across the range of initial concentration levels and exposure times. Consequently, these five materials, when used within filter treatment systems, may in the future prove valuable in reducing the adverse environmental impacts associated with the practice of agricultural subsurface drainage. NP 201 (now NP 211); Problem Area #6, Products #4 & #6.
2. New Germplasm Resources for the Genetic Improvement of Waterlogging Tolerance in American Soybean This study examined the responses of 22 soybean germplasm from Southeast Asia to waterlogging when grown in field plots, and also determined whether waterlogging tolerance of soybean can be tested in a screen house environment. Waterlogging at the early flowering stage reduced seed yield under field conditions between 37 and 100%. Tolerant plants averaged 29% taller than susceptible plants. Tolerance to waterlogging was associated with a higher number of pods per plant and more seeds per pod. Growth response to waterlogging stress, as determined by plant height, was correlated between the field and screen-house tests. While there was no correlation in yield reduction due to waterlogging between field and screen-house tests, screen-house tests could distinguish tolerant from susceptible genotypes based on plant survival and seed yield. Three genotypes, VND2, NamVang and ATF15-1 showed the best waterlogging tolerant responses under field and screen-house conditions. These lines provide new germplasm resources for the genetic improvement of waterlogging tolerance in American soybean. NP 201 (now NP 211); Problem Area #3, Product #1.
3. Cation Effects on Nitrate Mobility in an Unsaturated Soil Nitrate is a widespread contaminant found in both ground and surface water, and it typically moves through the soil profile first, especially if introduced via near-surface fertilizer application. Reducing adverse environmental impacts due to nitrate therefore requires, at least in part, a better understanding of the processes, particularly anion exclusion and adsorption, that govern nitrate mobility in soil. Transient unsaturated horizontal column experiments were carried out with a computer controlled syringe pump for the purpose of assessing accompanying cation effects on the anion exclusion or adsorption processes governing nitrate (NO3-) mobility in an unsaturated loam soil. Monovalent cations produced the greatest anion exclusion effects, followed by the divalent cations, while trivalent cations affected either minimal nitrate anion exclusion or anion adsorption. Results from this study can be used to improve computer models employed to predict nitrate movement through the soil profile, thereby allowing better nitrate fertilizer application management scenarios to be developed, which minimize adverse nitrate impacts on the environment. NP 201 (now NP 211); Problem Area #3, Product #1.
5. Significant Activities that Support Special Target Populations