Research Project: Assessment of Sediment and Chemical Transport Processes for Developing and Improving Agricultural Conservation Practices

Location: National Soil Erosion Research Laboratory

2024 Annual Report

Objectives
Objective 1: Quantify physical and chemical processes affecting sediment and nutrient transport in surface and subsurface waters. Sub-objective 1.A: Determine the dominant flow pathways for water and nutrient transport in tile-drained headwater watersheds. Sub-objective 1.B: Quantify the effects of landscape, surface, and climate conditions on erosion and related processes. Sub-objective 1.C: Evaluate how flow characteristics impact the ability of soils to behave as nutrient sources and sinks. Objective 2: Evaluate and improve the efficacy of novel soil and water conservation practices. Sub-objective 2.A: Optimize and demonstrate phosphorus removal structures and sorption materials for removing pollutants from water. Sub-objective 2.B: Determine effects of combined management practices on water quality. Objective 3: Enhance soil erosion and water quality models for improved predictions and management of agricultural and forested lands. Sub-objective 3.A: Improve natural resource model functionality and performance. (This is a non-hypothesis research sub-objective.) Sub-objective 3.B: Application of natural resource models and develop modeling techniques. Objective 4: Utilize long-term field and watershed datasets to enhance agricultural production and environmental quality in agroecosystems, and facilitate and support collaborations through the Conservation Effects Assessment Project (CEAP) and Long-Term Agroecosystem Research (LTAR) network. Sub-objective 4.A: Monitor fields and subcatchments in the St. Joseph River Watershed as part of the St. Joseph River CEAP and Eastern Corn Belt LTAR.

Approach
Hydrometric monitoring and conservative tracer analysis will be used to evaluate antecedent conditions on surface runoff and subsurface tile drainage flow generation and quantify surface and subsurface flow contributions to water quantity and quality. Runoff and groundwater within a tile-drained watershed will be analyzed to determine soil physical property effects and management practices on water quality. A lab rill channel and soil box will quantify sediment deposition and transport under different hydrologic conditions, and develop equations for process-based erosion models. Surface topographic techniques will be assessed to quantify spatial distribution of soil erosion and sediment deposition, and morphology of the drainage network. Collect high P soils from Western Lake Erie Basin and characterize for chemical and physical properties, followed by flow-through desorption experiments. Construct a subsurface P removal structure on an agricultural tile drain, using Fe-rich P filter media. Monitor inflow and treated water for P removal. Lab studies to assess different biochars at pollutant removal. Lab and field studies will assess conservation practice impacts on water quality at plot and field scales. Continued efforts on physical-based soil erosion model, including improved channel erosion simulation for ephemeral gullies and grass waterways, water quality routines for pollutant losses, and expanded subsurface tile drainage for better winter simulations and controlled drainage management. Changes to science model have resulted in separate code branches. We will unify these to have a single WEPP version applied by user agencies. Incorporate code from graduate student and other research. Conduct simulations using TauDEM, comparing results to both observed data and simulations using TOPAZ. Assess current code bases for WEPP and WEPS, and determine if common algorithms can be shared. Evaluate data needs of WEPP, WEPS, RHEM and RUSLE2 for common databases. Refactor WEPP code and maintain existing functionality. Use web services locally for desktop WEPP and WEPS, and for web-based applications to separate science and database logic from user interfaces. Expand web service software to fully support WEPP. Develop parallel processing for watershed applications, controlled by software service layer. Use parallelization on CPU and GPU processors. Update P-TRAP software, build mobile research/demo P removal structure, and help with P removal structures across the country. Climate change is resulting in elevated temperatures, more variable rainfall occurrence, and more intense rainfall events. Current conservation practices may be less effective in the future, and other practices may be needed to keep soil and pollutant losses to lower desired levels. Modeling studies will be used to assess impacts of climate change on erosion and off-site water quality, and effectiveness of control practices. Collaborate and support ongoing and future CEAP and LTAR projects and initiatives through sharing historical data from fields and watersheds, continued monitoring of field and watershed sites, and collection of new data and samples for cross-location analyses.

Progress Report
For Sub-objective 1.A, in an agricultural headwater watershed (CME2B) located within the St. Joseph River basin, 11 groundwater wells and nine passive runoff samplers are being monitored in addition to the watershed outlet. At each groundwater well and passive sampler location, water depth, water temperature, and electrical conductivity are being monitored at 10 min. intervals. Water samples are being collected weekly from both the groundwater wells and passive samplers and are being analyzed for nutrient concentration (Nitrate-Nitrogen (NO3-N), Ammonium-Nitrogen (NH4-N), Total Nitrogen (Total N), Dissolved Reactive Phosphorus (DRP), Total Phosphorus (Total P), solute tracers Chloride (Cl), and stable water isotopes. Soil samples were collected at each groundwater well installation (0-5, 5-15, 15-30, and 30-60 cm depths) to monitor changes in soil nutrient status. Data from the watershed described above (CME2B) and another headwater watershed in the St. Joseph River basin (BME2), are being used in conjunction with field and watershed data across the U.S. Midwest as part of the SWIFT (Stable Water Isotope Flowpath Tracing) Project being led by NSERL (Sub-objective 1.A). Six sites across Long-Term Agroecosystem Research (LTAR) locations in Iowa, Minnesota, and Ohio, and one partner location in Ontario, Canada, are using common methodology to collect data on water sources and flow pathways. Each site is sending subsamples of water to NSERL for analysis of stable water isotopes. This project will continue for another year depending on climate and/or hydrologic conditions during monitoring. Please note that Sub-objective 1.B - Quantify the effects of landscape, surface, and climate conditions on erosion and related processes – has not been investigated since the two scientists responsible for this section have either retired or left the research unit. We are currently recruiting for a new scientist that may address this sub-objective. With regards to Sub-objective 1.C, all topsoils have been evaluated in their ability to desorb P under two different flow regimes. The two flow rates representing slower matrix flow and faster preferential flow resulted in vastly different P desorption quantities and kinetics. A manuscript is currently in progress. We hope to utilize this data in updating models that predict dissolved P transport. Much progress has been made on Sub-objective 2.A. The P removal structure, which contains a steel turnings- gravel mixture, has been monitored for P removal performance and pH-metals discharge. This unit is especially unique in that it is the first ever steel turnings filter in which water flows from the bottom-upward. It appears that periods of no-flow do not result in excessive anaerobic conditions that re-release P from the filter media. The pH of discharge was near neutral, and no trace metals were released to the environment. Other media have been collected from various industry stakeholders and are being evaluated for P removal in the lab; depending on success, some materials may be pelletized and re-evaluated. Related to the P removal structures, a series of training videos were released to aid engineers in designing structures (Goal 3A.4); further work is necessary to release similar videos for a different audience, specifically, conservationists that are not engineers. Further, several more P removal structures were designed through various collaborators in a variety of states, including Ohio, Indiana, Iowa, Wisconsin, and Maryland, as well as Canada. Some of these units were constructed. The mobile demonstration P removal laboratory was completed and exhibited recently at the annual Indiana MS4 Stormwater Conference. Related to Sub-objective 2.A.2, sorption isotherms were conducted to investigate the sorption capacity of spent railroad tie-derived biochars (700 degrees C) to remove nitrate and phosphate in water, nutrients known to pollute waterways. Under the conditions of this study, this biochar did not remove these nutrients. Other pollutants (for example, atrazine and cadmium) as a proxy for pesticides and heavy metals will be used in sorption isotherms in the Fall of 2024. Work on Sub-objective 2.B.1 included installation of lysimeters in mid-June 2024 at the Throckmorton Purdue Agricultural Center (TPAC) research plots to investigate the impact of two conservation practices, no-till and winter crops, on nutrients and heavy metals in solution. This is an ongoing study. Chemical analysis of runoff water from rainfall simulations is completed. This research was conducted to investigate the effects of gypsum on P losses from poultry-litter-treated plots. The results will be presented at the 2024 International American Society of Agronomy – Soil Science Society of America (ASA-SSSA) meeting. We also conducted indoor rainfall simulations to investigate the impact of cereal rye (as a winter cover crop) on sediment and water runoff. NSERL scientists also organized a symposium and session at the 2023 International ASA-SSSA-CSSA annual meeting on gypsum as a soil amendment to improve soil health and water quality. Related to Objective 3, ”Enhance soil erosion and water quality models for improved predictions and management of agricultural and forested lands”, efforts continue with improvements to and modifications of the Water Erosion Prediction Project (WEPP) science model and user interfaces. A web service has been updated that runs the WEPP watershed model. Database templates for simulation channel parameters and impoundment parameters are being tested to support typical Natural Resources Conservation Service (NRCS) conservation management options related to channel erosion. Together with cooperators at Colorado State University and NRCS improvements to the online Geographic Information System (GIS) user interface are currently being tested to evaluate WEPP simulations and ease-of-use. During the past year optimizations have been done to the WEPP watershed service and user interface to allow multiple watershed simulations to be combined to cover an area of interest. These simulations allow detailed spatial soil loss estimates to be presented as GIS maps. In addition, a new Geospatial Interface for WEPP (GeoWEPP) was completed and validated using the freely available Quantum GIS (QGIS). For Objective 3, the WEPP Windows interface program, which is a standalone Windows program, has been updated to support both the previous version of the WEPP model as well as the current version. Significant improvements to the user interface software have been made in the areas of using open-source components and also being able to use web services to retrieve data as needed. The updated version of the WEPP Windows interface is currently being tested before making it more widely available. As part of accessing the overall structure of the WEPP model software an automatic documentation generator has been used to produce Hypertext Markup Language (HTML) formatted pages pulling code comments for subroutines and data elements. This type of documentation also determines program flow and shows areas where model documentation can be improved. NSERL researchers are actively engaged in various CEAP and LTAR research coordination efforts at the national scale including the watershed monitoring efforts through CEAP and LTAR (Sub-objective 4.A). Current network collaborations include the LTAR Agroecosystems Group with focus on water and wind erosion across various agroecosystems (led by ARS scientist at Las Cruces, New Mexico) and the newly created LTAR Soil Erosion Subgroup co-led by ARS scientists at Oxford, Mississippi, and West Lafayette, Indiana, the National Legacy Phosphorus Project (led by ARS scientist at Fort Collins, Colorado), LTAR Drainage Group Microplastics Project (led by ARS scientist at St. Paul, Minnesota), LTAR Drainage Group Edge-of- Field Practices Project (led by ARS scientist in St. Paul, Minnesota), LTAR Algal Eutrophication Project (led by ARS scientist in Oxford, Mississippi), and the LTAR Remote Sensing Working Group (led by ARS scientist in Maricopa, Arizona).

Accomplishments
1. The cost of removing phosphorus from drainage water. Phosphorus is a required nutrient for crop growth, but excessive soil concentrations can lead to the degradation of aquatic ecosystems and poor drinking water quality when it moves from soil to water bodies. A team of researchers that included ARS in West Lafayette, Indiana, conducted a detailed economic analysis of different phosphorus removal structures that can filter and remove dissolved phosphorus before it reaches a water body. Several types of systems were considered: modified inlets for filtering surface water, buried tile drainage filters, surface filter beds, as well as various types of filter media and sizes. Overall, the most economical phosphorus removal structure was a modified inlet that contained a steel turnings-gravel byproduct as filter media. Larger phosphorus removal structures are more economical and efficient than smaller ones. This information will help guide conservationists and policy makers in making decisions about what types of phosphorus removal structures to design and fund.

2. Developed web-based tool soil erosion tool to assess NRCS soil conservation practice. ARS researchers in West Lafayette, Indiana, developed a new Water Erosion Prediction Project (WEPP) model and user interface version. This updated version for the Natural Resources Conservation Service (NRCS) can be used in their field offices for conservation planning. The model calculates runoff, erosion, deposition, and other values. This research is the result of working with NRCS and other agencies over more than a decade. To meet NRCS’ needs the team updated climate, soils, and management databases. A risk analysis shows the variations in soil loss predictions. Plant and field management systems are comparable to those in other ARS erosion models. The WEPP model helps soil conservationists and policy makers in making better decisions: What soil conservation practices reduce soil erosion and sediment loss to acceptable levels. The model runs on a webpage at Colorado State University. It is also available to any stakeholder at: https://brenton.nserl.purdue.edu/wepp.

3. Updated the WEPP model and Windows interface to aid in monitoring runoff and soil loss. The Water Erosion Prediction Project (WEPP) model was updated with the latest science. This is the first public release since 2012. It includes all model changes based on a ten-year team effort by ARS researchers in West Lafayette, Indiana, and the Natural Resources Conservation Service (NRCS). The WEPP Windows interface allows users to fully design their simulations. Users create and can change all slope, soil, cropping, climate, channel, and impoundment inputs. The software utilizes NRCS soils, crop, and management databases. It also includes the updated climate database for the United States. The WEPP tool is used by other scientists, faculty, and students around the world to estimate runoff, soil loss, and sediment delivery. Example datasets are also included with this release.

4. Developed and released a new Geospatial Interface for WEPP (QGeoWEPP) to identify areas of large soil erosion. ARS researchers in West Lafayette, Indiana, completed and validated an updated GeoWEPP program. It uses freely available geographic information system (GIS) software. QGeoWEPP is available for download for free from the NSERL website. The Water Erosion Prediction Project (WEPP) model is easy to apply to simple hillslopes and farm fields. QGeoWEPP enables users to develop hillslopes from publicly available geospatial data. The QGeoWEPP tool makes it very easy for a user to also build watershed simulations. The new tool also includes validation data sets as examples. The model and validation results were recently described in a peer-reviewed journal article. Outputs show spatial soil loss and deposition problem locations. Those locations can then be used to design soil conservation measures. The QGeoWEPP software helps to inform scientists and soil conservationists about soil erosion at locations. Then soil conservation practices can help to reduce those soil erosion and sediment losses.

Review Publications
Wood, T.C., Smiley, P.C., Gillespie, R.B., Gonzalez, J.M. 2024. Identifying the environmental variables that predict crayfish assemblage structure in agricultural headwater streams. Freshwater Science. 43(1):18-36. https://doi.org/10.1086/729307.
Villela, J. M., Anache, J. A. A., Watanabe, A. M., Flanagan, D. C., Wendland, E. M., and Crestana, S. 2023. Performance evaluation of a water erosion tracer using plot-scale experiments and process-based modeling. International Soil and Water Conservation Research. 11(4): 622-632. https://doi.org/10.1016/j.iswcr.2023.05.003
Zhao, Y., Zheng, R., Zheng, F., Zhong, K., Fu, J., Zhang, J., Flanagan, D.C., Xu, X., Li, Z. 2023. Spatiotemporal distribution of agrometeorological disasters in China and its impact on grain yield under climate change. International Journal of Disaster Risk Reduction. https://doi.org/10.1016/j.ijdrr.2023.103823.
Mumbi, R., Williams, M.R., Penn, C.J., Camberto, J.J. 2024. Accumulation of soil phosphorus within closed depressions of a drained agricultural watershed. Soil Science Society of America Journal. https://doi.org/10.1002/saj2.20671.
Williams, M.R., Ford, W.I., Mumbi, R. 2023. Preferential flow in the shallow vadose zone: Effect of rainfall intensity, soil moisture, connectivity, and agricultural management. Hydrological Processes. https://doi.org/10.1002/hyp.15057.
Ding, F., Li, S., Lu, J., Wang, Q., Lin, G., Sardans, J., Penuelas, J., Wang, J., Rillig, M., Penn, C.J. 2023. Consequences of 33 years of plastic film mulching and nitrogen fertilization on maize growth and soil quality. Environmental Science and Technology. https://doi.org/10.1021/acs.est.2c08878.
da Silva Sandim, A., Rodrigues da Silva, L.J., Fernandes Deus, A.C., Penn, C.J., Bull, L.T. 2023. Phosphorous fractions in weathered tropical soils after application of conventional and alternative P fertilizers. Journal of Soil Science and Plant Nutrition. https://doi.org/10.1007/s42729-023-01426-w.
Scott, I., Scott, F., McCarty, T., Penn, C.J. 2023. Techno-economic analysis of phosphorus removal structures. Journal of Environmental Science and Technology. https://doi.org/10.1021/acs.est.3c02696.
Ai, H., Zhang, K., Penn, C.J., Zhang, H. 2023. Phosphate removal by low-cost industrial byproduct iron shavings: Efficacy and longevity. Water Research. https://doi.org/10.1016/j.watres.2023.120745.
Zhang, H., Renschler, C.S. 2024. QGeoWEPP: An open-source geospatial interface to enable high-resolution watershed-based soil erosion assessment. Environmental Modelling & Software. https://doi.org/10.1016/j.envsoft.2024.106118.
Buseman, A., Penn, C.J., Charbonnet, J.A., Kaleita, A.L., Long, L.M., Soupir, M.L. 2023. Soil phosphorus in farmed potholes: assessing concentrations and testing export mitigation with steel media. Journal of the ASABE. https://doi.org/10.13031/ja.15759.