Research Project: Developing and Evaluating Strategies to Protect and Conserve Water and Environmental Resources While Maintaining Productivity in Agronomic Systems

Location: Soil and Water Management Research

2023 Annual Report

Objectives
Objective 1: Quantify the transport and fate of nutrients, agrochemicals, and contaminants in managed landscapes and investigate controlling mechanisms. Sub-objective 1A: Determine the persistence and degradation of agricultural inputs and environmental contaminants and factors that control availability to biotic or abiotic (i.e., soil mineral interaction, soil temperature, moisture, and oxidation) processes. Sub-objective 1B: Measure and model the occurrence, export, and transport of agricultural inputs and environmental contaminants to and within surface water and ground water resources. Objective 2: Develop management approaches to reduce adverse impacts of agronomic practices on water quality and quantity. Sub-objective 2A: Examine conventional (BAU) and aspirational (ASP) management practices and investigate new technologies and approaches that will enhance food production while protecting water resources. Sub-objective 2B: Investigate the ecosystem services of turf.

Approach
The challenge we face with a growing world population is to increase agricultural production to meet demands while maintaining environmental quality. Critical to this challenge is protecting the integrity of water resources, which is the foundation of our project’s objectives that quantify the transport and fate of agricultural inputs and contaminants in managed landscapes (objective 1) and develop management approaches to reduce adverse impacts of agronomic practices on water quality and quantity (objective 2). Laboratory, plot level, and watershed-scale investigations will encompass one or more of three over-arching approaches that include: (1) measurements to identify occurrence of contaminants and their sources; (2) management to mitigate contaminants; and (3) modeling to evaluate broader impacts of contaminants and effectiveness of conservation practices or mitigation strategies. Research addressing the first objective will measure the persistence and degradation of agricultural inputs and environmental contaminants and factors that control their availability (subobjective 1a). This includes improving our understanding of biochar aging mechanisms that impact agrochemical sorption and degradation (goal 1a.1), and characterizing contaminants in urban agricultural systems and reducing contaminant availability with management practices (goal 1a.2). In addition, we will measure and model the occurrence, export, and transport of agricultural inputs and environmental contaminants to and within surface water and ground water resources (subobjective 1B). This includes mapping sources and sinks of contaminants in agricultural watersheds to evaluate the mitigation efficacy of management practices (goal 1b.1), and characterizing pesticide sorption to agricultural microplastics (goal 1b.2). Research addressing the second objective will examine conventional and aspirational management practices and investigate new technologies and approaches that will enhance food production while protecting water resources (subobjective 2a). This includes the evaluation of perennial and annual cover crop management practices to reduce negative impacts of row crop production on water quality (goal 2a.1), community-scale denitrifying bioreactor for mitigating nutrient and sediment losses from subsurface tile drained landscapes (goal 2a.2), and synergistic benefits of additives with optimized nitrogen management to reduce loss of soluble nitrogen from cropping systems to ground and surface waters (hypothesis 2a.3). We will also investigate the ecosystem services of turfgrass (subobjective 2b), one of the largest crops grown in the United States, to measure its effectiveness to mitigate transport of roadside contaminants to surface waters (goal 2b.1) and to evaluate the effect of soil moisture and grass species on N-cycling (goal 2b.2). Results of this research will formulate guidelines to enhance the sustainability of agriculture and protect water quality, thus improving water resource security and safeguarding the environment and human and animal health. Data from this project plan will also contribute to Long-Term Agroecosystem Research.

Progress Report
In support of Objective 1, goal 1A.1, an additional five volunteers have been included in the research effort as well as developing connections with the Sustainable Farmers Association in Minnesota to assist in identify additional farmers willing to participate in this research effort. We are hopeful that this recruitment will be completed by Fall of this year. Additionally, analytical methodology has been developed to analyze returned samples for alterations in fundamental characteristics (i.e., cation exchange capacity and surface area analysis). Collaborative efforts are underway with the CHARnet network within ARS for characterization assessments and incorporation of this project’s data into the biochar selection tool being developed at the Corvallis, Oregon location. In support of Objective 1, goal 1A.2, soils were collected from multiple locations throughout a metropolitan area in Minnesota, investigating locations with potential for urban agriculture. Targeted chemical contaminants have been determined and methods for their extraction and analytical identification are under evaluation. Collaborative research with university scientists in St. Paul, Minnesota, has also begun to evaluate contamination of agricultural land with microplastics following application of biosolids from municipal wastewater treatment. Additionally, a third field season comparing three methods of raised bed urban food production will be completed this fall to enhance a data set initiated in the previous project plan (Objective 2, goal 2D, ending 9/2022) and related to the current project plan, Objective 1, goal A.2. In support of Objective 1, goal 1B.1, high frequency optical water probes have been deployed at fixed locations in High Island Creek watershed to measure export of nitrate (NO3-) and other water quality parameters. Additionally, complementary probes have been deployed from an inflatable boat known as a Packraft. Data collected from the moving Packraft platform includes GPS coordinates. We have developed a framework to link water quality data to the stream channel network to allow comparison of repeated sampling campaigns, resulting in the ability to evaluate how watershed behavior changes over time and hydrologic conditions. Collection of information reporting plastic polymers used in agriculture and obtaining samples of agricultural plastics is underway in support of Objective 1, goal 1B.2. Specialized equipment enabling pyrolysis of solid samples for identification of their plastic polymers was purchased, and method evaluation and optimization is taking place. In related research supporting Sub-objective 1B, scientists from St. Paul, Minnesota, collected stream water and atmospheric deposition (precipitation and dry free-fall) throughout the year from an undrained agricultural watershed, which showed greater quantities of microplastics are leaving the watershed in the stream water relative to entering the watershed in the atmosphere – suggesting there are important sources of microplastics within this undrained agricultural watershed. Additionally, in collaboration with USDA-ARS Long-Term Agroecosystem Research (LTAR) network, sampling of tile water in drained agricultural watersheds in Minnesota, Iowa, Illinois, and Ohio has begun. In support of Objective 2, goal 2A.1, new research plots have been established at Lamberton, Minnesota, to study the impacts of kura clover living mulch (KCLM) on quality of water in subsurface tile drainage, a common practice in the Upper Midwest. The kura clover is in its second year of establishment with management practices scheduled to begin in FY24. Ongoing complementary experiments are being conducted at Rosemount, Minnesota, with those experiments designed to quantify the effects of row establishment methods, timing, and fertilizer application on performance of corn in a KCLM system. We recognized that the kura clover has many characteristics that suggest it would be an excellent ground cover in solar farms, providing high infiltration rates and erosion protection while offering an opportunity to maintain agricultural production (hay and honey). A cooperative agreement was established to evaluate kura clover in a large solar installation in Rosemount, Minnesota. Collaborators have allocated 40 acres of their solar array for planting of kura clover, and scientists in St. Paul, Minnesota, will install sensors to measure distribution of solar radiation, soil moisture, temperature, and biomass production. This research supports Objective 2, goal 2A.1. Additionally, in support of Objective 2, goal 2A.1, one year of water flow and chemistry data were collected on the two paired watersheds. These data, with the previous year’s data, were graphed to show excellent pairing of tile drainage outflow and nitrogen losses from the two watersheds. The relationships (R2) were 0.96 for flow and 0.97 for nitrogen loss (1.0 being a perfect relationship). In support of Objective 2, goal 2A.2, the laboratory bioreactor experiment was completed, and field bioreactor data were collected, and hydraulic tracer tests have been conducted on each of the three bioreactor beds. In support of Objective 2, hypothesis 2A.3, laboratory microcosm experiments examining the effectiveness of procyanidin compounds for decreasing nitrous oxide (N2O) production in fertilized soils were conducted. The experiments compared the effectiveness of procyanidin compound mixtures obtained from two different commercial sources and quantified the stability of the chemicals under different storage conditions. The experiments showed that one source was clearly more effective than the other and that storage had minimal impacts on its effectiveness. Additional experiments examined the effectiveness of individual compounds within the mixture and found that some specific compounds had opposing effects that detracted from the effectiveness of the mixture as a whole, suggesting that further purification of the mixture could enhance its efficacy. A manuscript reporting these results was submitted and is currently in review. It was determined that the cost of using either commercially available mixture would be prohibitive for use in a field experiment or actual application. Therefore, field experiment will utilize a commercially available inhibitor (dicyandiamide) that has been previously studied and found to be effective under a range of conditions. In support of Objective 2B, goal 2B.1, researchers in St. Paul, Minnesota, collected roadside snow samples in urban, suburban, and rural locations and began characterizing roadside contaminants. Initial analyses included filtration and microscopic quantified of particulates such as tire wear with development of confirmation analysis by pyrolysis and identification of characteristic polymers to follow. Additionally, the design and fabrication of a portable device for collection of contaminants in wash-off from roadside turf during temperate and warm months is ongoing. In support of Objective 2, goal 2B.2, soil samples from the University of Minnesota turf research plots have been collected this Spring and additional sampling are planned mid-Summer and early Fall. These soil samples will be utilized to determine the dependency of greenhouse gas production on soil moisture content for turf systems in the Upper Midwest. Additionally, as part of a cooperative agreement with collaborators in Madison, Wisconsin, and in support of Sub-objective 2B, we evaluated soil under managed turf (lawns, sports fields) and agricultural or native lands to measure soil microbial diversity and markers of soil health. A manuscript of the findings is in preparation. Additionally, collaborators in Madison, Wisconsin, estimated golf course water use efficiency through modifications of the agricultural version of the Integrated Biosphere Simulator model, Agro-IBIS.

Accomplishments
1. World-first scale up of bioreactor technology to treat watersheds and increase nitrate removal. Mississippi River Basin states struggle to reduce agricultural nonpoint source nitrate pollution that contributes to Gulf of Mexico hypoxia, which alters ecosystem services and negatively impacts fisheries. ARS researchers in St. Paul, Minnesota, confirmed the performance of a world-first, three-bed bioreactor designed to remove nitrate in tile drainage from large areas, ˜1 square mile, rather than single fields. They validated the performance of this unique system, reporting the fraction of watershed flow treated (55%) and nitrate removal potential (18%) over the first year and a half of operation. Sedimentation issues encountered were solved by designing and implementing a sensing and exclusion system. The solution is important to maintaining the performance of and increasing the service life of bioreactors deployed at this scale. The system provides another tool in the toolbox for state and local conservation professionals tasked to reduce agricultural nonpoint nitrate loads.

2. Enhanced bioreactor effectiveness in cold temperatures through increased carbon availability. Woodchip denitrifying bioreactors reduce agricultural tile drainage nitrate loads, but performance under cold temperature is poor due to C limitations. ARS researchers in St. Paul, Minnesota, comprehensively evaluated N removal and C dynamics when using agricultural residues (corn cobs) versus woodchips and when dosing woodchips with a readily available C source (i.e., acetate). Corn cobs improved nitrate removal rates by four times over woodchips. Acetate addition to woodchips increased nitrate removal rates by more than an order of magnitude over woodchips alone in a laboratory study. The lab results informed a replicated on-farm field demonstration that confirmed a three-fold increase in nitrate removal rate for C-dosed woodchips. The results are encouraging for researchers working to improve the effectiveness of denitrifying bioreactors in higher latitudes around the world.

3. Inoculated field woodchip bioreactors with cold-adapted denitrifying bacteria. Woodchip denitrifying bioreactors have shown poor performance in cold temperatures. To address this problem, ARS researchers in St. Paul, Minnesota, were the first to identify and isolate cold-adapted denitrifying bacteria and inoculate them into woodchip beds, a process known as bioaugmentation. The researchers isolated cold-adapted denitrifiers indigenous to existing woodchip beds and added them to field-based, pilot-scale beds. Although the results showed that bioaugmentation did not result in a statistically significant increase in nitrate removal across the entire experiment, for a portion of the experiment, outlet nitrate concentrations were lower and removal rates greater (33%) for bioreactors with bioaugmentation versus the woodchip control. The findings are a step forward for researchers working on the same problem and underscore the need to overcome the issue of maintaining the abundance of inoculated strains under real world conditions.

Review Publications
Law, J.Y., Slade, A., Hoover, N., Feyereisen, G., Soupir, M. 2022. Amending woodchip bioreactors with corncobs reduces nitrogen removal cost. Journal of Environmental Management. 330(15). Article 117135. https://doi.org/10.1016/j.jenvman.2022.117135.
Christianson, L.E., Wickramarathne, N., Johnson, G.M., Feyereisen, G.W. 2022. No/low-cost chipped woody debris nutrient composition benefits and tradeoffs for denitrifying bioreactors. Bioresource Technology Reports. 20. Article 101237. https://doi.org/10.1016/j.biteb.2022.101237.
La Scala, N., Martinez, A.S., Spokas, K.A. 2023. CO2 emission and its interface with soil organic matter: A multidisciplinary vision. In:Bettiol, W., Silva, C.A., Martin-Neto, C.E.P., de Andrade, C.A., editors. Soil Organic Matter.Embrapa, Brazillia, Brazil. p. 297-316.
Gamiz, B., Velarde, P., Spokas, K.A., Cox, L. 2022. The role of nanoengineered biochar activated with Fe for sulfanilamide removal from soils and water. Molecules. 27(21). Article 7418. https://doi.org/10.3390/molecules27217418.
Feyereisen, G.W., Wang, H., Wang, P., Anderson, E.L., Jang, J., Ghane, E., Coulter, J.A., Rosen, C.J., Sadowsky, M.J., Ishii, S. 2023. Carbon supplementation and bioaugmentation to improve denitrifying woodchip bioreactor performance under cold conditions. Ecological Engineering. 191. Article 106920. https://doi.org/10.1016/j.ecoleng.2023.106920.
Toczydlowski, A., Slesak, R., Venterea, R.T., Spokas, K.A. 2023. Pyrolysis temperature has greater effects on carbon and nitrogen biogeochemistry than biochar feedstock when applied to a red pine forest soil. Forest Ecology and Management. 534. Article 120881. https://doi.org/10.1016/j.foreco.2023.120881.
Feyereisen, G.W., Ghane, E., Schumacher, T.W., Dalzell, B.J., Williams, M.R. 2023. Can woodchip bioreactors be used at a catchment scale? Nitrate performance and sediment considerations. Journal of the ASABE. 66(2):367-379. https://doi.org/10.13031/ja.15496.
Dalzell, B.J., Fissore, C., Nater, E. 2022. Topography and land use impact erosion and soil organic carbon burial over decadal timescales. Catena. 218. Article 106578. https://doi.org/10.1016/j.catena.2022.106578.
Elias, E.H., Tsegaye, T.D., Hapeman, C.J., Mankin, K.R., Kleinman, P.J., Cosh, M.H., Peck, D.E., Coffin, A.W., Archer, D.W., Alfieri, J.G., Anderson, M.C., Baffaut, C., Baker, J.M., Bingner, R.L., Bjorneberg, D.L., Bryant, R.B., Gao, F.N., Gao, S., Heilman, P., Knipper, K.R., Kustas, W.P., Leytem, A.B., Locke, M.A., McCarty, G.W., McElrone, A.J., Moglen, G.E., Moriasi, D.N., OShaughnessy, S.A., Reba, M.L., Rice, P.J., Silber-Coats, N., Wang, D., White, M.J., Dombrowski, J.E. 2023. A vision for integrated, collaborative solutions to critical water and food challenges. Journal of Soil and Water Conservation. 78(3):63A-68A. https://doi.org/10.2489/jswc.2023.1220A.
Xiao, K., Griffis, T.J., Lee, X., Xiao, W., Baker, J.M. 2023. A coupled equilibrium boundary layer model with stable water isotopes and its application to local water recycling. Agricultural and Forest Meteorology. 339. Article 109572. https://doi.org/10.1016/j.agrformet.2023.109572.
Dolph, C., Cho, S., Finlay, J., Hansen, A., Dalzell, B.J. 2023. Predicting high resolution total phosphorus concentrations for soils of the Upper Mississippi River Basin using machine learning. Biogeochemistry. 163:289–310. https://doi.org/10.1007/s10533-023-01029-8.
Leverich, L.M., Kaiser, D.E., Feyereisen, G.W. 2022. Influence of soil test phosphorus level and leaching volume on phosphorus leaching. Soil Science Society of America Journal. 86(5):1280–1295. https://doi.org/10.1002/saj2.20452.