Location: Soil Drainage Research
2022 Annual Report
Objectives
Objective 1: Elucidate field and instream governing processes that control water quality and ecological response.
Goal 1.1: Develop water table, soil moisture, and evapotranspiration measurement capacity within a subset of EOF network sites to better understand the water balance in tile drained landscapes.
Hypothesis 1.2: The majority of observed edge-of-field P losses are attributable to old soil P rather than recently applied P fertilizers.
Hypothesis 1.3: Preferential flow to subsurface tile drains are dominated by contributions from a relatively narrow band of the soil surface extending less than 1 m on either side of the drain.
Objective 2: Quantify the response of ecosystem services (e.g., water quality, habitat, and biodiversity) to conservation practice implementation.
Hypothesis 2.1: Implementation of conservation/aspirational practices (ASP) will significantly reduce edge-of-field surface and subsurface nutrient loss compared to business as usual (BAU) practices.
Hypothesis 2.2: Including two or more conservation practices (stacking) will provide greater nutrient loss reductions compared to single practice implementation.
Hypothesis 2.3: Improvements in soil health indicators will be associated with reduced edge-of-field nutrient losses.
Hypothesis 2.4: Installation of instream inserts within an agricultural headwater stream will create riffle pool sequences that will increase instream habitat diversity and improve fish community integrity at the microhabitat spatial scale.
Hypothesis 2.5: Installation of instream inserts in conjunction with channel rerouting and wetland creation will increase instream habitat diversity, improve fish community integrity, increase dissolved oxygen concentrations, and reduce downstream transport of nutrients. Hypothesis 2.6: Channelized agricultural headwater streams with greater instream habitat diversity will exhibit less nutrient concentrations and less within-season variability in nutrient concentrations and greater fish biodiversity and abundance.
Objective 3: Contribute to LTAR network science, data synthesis, and model development through data collection and development/assessment of predictive tools.
Hypothesis 3.1: Aspirational management systems (ASP) will improve soil health indicators compared to business-as-usual (BAU), but the degree of improvement will depend on site-specific factors.
Goal 3.2: Identify the best environmental predictors of fish community structure in agricultural headwater streams in the Eastern Corn Belt LTAR node.
Goal 3.3: Collect and synthesize data for Ohio high priority, agricultural tile drained watersheds.
Approach
Improved drainage, including subsurface tile and channelized streams, is required for sustainable agricultural crop production on an estimated 200 million ha of cropland worldwide. Another 425 million ha could benefit from improved drainage. The Midwest U.S. produces roughly 65% of the Nation’s annual corn and soybean production, largely as a result of artificial drainage. However, improved drainage has been linked to downstream water quality issues that include harmful algal blooms (e.g., Lake Erie and Gulf of Mexico) and hypoxia (e.g., Gulf of Mexico). Future climate predictions for the Midwest U.S. indicate more intense fall and spring storms and increasing temperatures that will heighten the importance of efficient drainage systems that maintain or improve ecosystem function and are in balance with new and/or enhanced production management practices, referred to as conservation/aspirational practices. Voluntary, incentive, and regulatory efforts have been applied to address agricultural nutrient loss and ecosystem function; yet, the problems persist. A combination of plot, field, and stream-scale research will be used to: isolate and understand the governing processes that control hydrological, water quality, and ecological responses; assess existing and novel management and conservation practices for their ability to reduce nutrient loss, enhance stream habitat and increase aquatic biodiversity; and synthesize the findings into improved simulation algorithms/scenarios for existing models and/or the development of new predictive tools. Successful completion of the proposed research will provide producers; certified crop advisors; extension specialists; researchers; drainage industry; conservationists; local, state, and federal action agencies; Western Lake Erie Basin (WLEB) and other watershed stakeholders; and decision/policy makers a better understanding of the governing controls and processes of nutrient dynamics in tile drained landscapes; quantitative assessments to develop and inform design, selection, and implementation of conservation practices; and enhance or improve the development and testing of prediction technologies.
Progress Report
This is the first report for this new project which began in March 2022 and continues research from the previous project, 5080-13210-002-00D, “Agricultural Water Management in Poorly Drained Midwestern Agroecosystems”. Please see the report for the previous project for additional information.
Objective 1: Progress continues to be made on developing water table, soil moisture, and evapotranspiration measurement capacity within a subset of the edge-of-field network. Ground water wells have been installed in four fields while soil moisture sensors have already been installed in the majority of fields. We have two mobile flux towers that we are testing and they will be moved to two different fields where soil moisture and water table depth are measured, permitting a better understanding of the water balance in tile drained landscapes.
Significant progress continues to be made in investigating the contributions of old phosphorus and new phosphorus to water quality. An adaptation of the weighted regressions on time, discharge, and season method (WRTDS) is being applied to edge-of-field data. The method has been applied to data from four edge-of-field sampling points and efforts are underway to apply the methods to the broader data set. Additionally, the findings are being leveraged for a national scale project investigating old and new phosphorus from high priority watersheds across the US.
With respect to investigating preferential flow, a methodology has been established and discussion on plot identification has been initiated.
Objective 2. Significant progress continues to be made on assessing the water quality benefits of single and combined conservation practices. Field scale experiments are already underway to explore the impacts of random vs systematic tile drainage, fertilizer placement, source and rate, tillage vs no tillage, and the use of cover crops. Supplemental plot scale experiments on fertilizer placement are ongoing. Similarly, experiments to investigate the stacking or combination of practices are ongoing. Specifically, investigating the impacts of woodchip bioreactors in combination with phosphorus removal structures, the combined effect of in-field practices combined with a two-stage ditch, and the combination of two in-field practices (fertilizer rate and cover crops) are all ongoing. On many of the field, soil samples have and will continue to be collected to evaluate the effects of the various practices on soil health/quality.
With respect to the ecology component, we have identified sampling site locations and are working to obtain landowner permission to sample. Additionally, we have been developing field testing sampling methods for collection of fishes at microhabitat scale. Grab samples for nutrients is ongoing and instream habitat and fishes were sampled this spring. Second sample of instream habitat and fishes to be collected in the fall. Additionally, measurement of stream metabolism and associated hydrological, water chemistry, and riparian habitat measurements were recently completed and another round will occur in the fall. Currently developing protocol and ordering supplies for nutrient addition experiment to be conducted later this year. We have identified sites for reconnaissance sampling of instream habitat diversity and seeking landowner permission to sample.
Objective 3: Plans for soil sampling and analysis across the edge-of-field network to assess soil quality between aspirational and business as usual practices is on target. All supplies are in hand and sampling will occur after crop harvest.
Collaboration with various LTAR working groups is ongoing. Specific to the drainage working group, sites for isotope study have been identified and sampling will commence this summer.
Accomplishments
Review Publications
Allred, B.J., Martinez, L.R., Khanal, S., Sawyer, A., Rouse, G. 2022. Subsurface drainage outlet detection in ditches and streams with UAV thermal infrared imagery: preliminary research. Agricultural Water Management. Article 107737. https://doi.org/10.1016/j.agwat.2022.107737.
Williams, M.R., Welikhe, P., Bos, J.H., King, K.W., Akland, M., Augustine, D.J., Baffaut, C., Beck, G., Bierer, A.M., Bosch, D.D., Boughton, E., Brandani, C., Brooks, E., Buda, A.R., Cavigelli, M.A., Faulkner, J., Feyereisen, G.W., Fortuna, A., Gamble, J.D., Hanrahan, B.R., Hussain, M., Kohmann, M., Kovar, J.L., Lee, B., Leytem, A.B., Liebig, M.A., Line, D., Macrae, M., Moorman, T.B., Moriasi, D.N., Nelson, N., Ortega-Pieck, A., Osmond, D., Pisani, O., Ragosta, J., Reba, M.L., Saha, A., Sanchez, J., Silveira, M., Smith, D.R., Spiegal, S.A., Swain, H., Unrine, J., Webb, P., White, K.E., Wilson, H., Witthaus, L.M. 2022. P-FLUX: A phosphorus budget dataset spanning diverse agricultural production systems in the United States and Canada. Journal of Environmental Quality. 51:451–461. https://doi.org/10.1002/jeq2.20351.
