Developing Agricultural Practices to Protect Water Quality and Conserve Water and Soil Resources in the Upper Midwest United States

Goals / Objectives
1. Develop irrigation and drainage strategies in the North Central United States to protect water and soil resources a. Determine the potential of amendments to mitigate leaching and contamination of groundwater from agricultural operations. b. Identify materials and designs that will maximize contaminant removal from subsurface drainage water. 2. Identify and test innovative management practices to reduce potential adverse impacts on water quality or conserve water resources. a. Evaluate the effectiveness of low-input turf and management practices to reduce contaminant transport with runoff. b. Identify and test management practices to reduce reactive nitrogen leakage from dairy farming systems. c. Determine the impact of perenniallizing practices on the nutrient and water balances of corn/soybean systems. d. Determine the influence of management practices and water conservation strategies on water use and the occurrence and fate of contaminants in urban agriculture. 3. Conduct research as part of the LTAR network, and in concert with similar long-term, land-based research infrastructure in the U.S., use the Upper Mississippi River Basin LTAR site to improve the observational capabilities and data accessibility of the LTAR network and support research to sustain or enhance agricultural production and environmental quality in agroecosystems characteristic of the Upper Mississippi River Basin. Research and data collection are planned and implemented based on the LTAR site application and in accordance with the responsibilities outlined in the LTAR Shared Research Strategy, a living document that serves as a roadmap for LTAR implementation. Participation in the LTAR network and test innovative management practices to reduce potential adverse impacts on water quality or conserve water resources includes research and data management in support of the ARS GRACEnet and DAWG projects.

Project Methods
Protecting the integrity and supply of our water resources is one of the most important issues we will face this century and therefore the foundation of our project¿s objectives (objectives 1 and 2). Our research approach requires laboratory to field scale investigations focusing on two strategies, prevention and mitigation. With the prevention strategy we will identify and understand the fate of potential water contaminants (e.g. agrochemicals: fertilizer, pesticides; anthropogenic compounds) and develop practices to prevent or minimize the off-site transport of contaminants from their site of application or point of origin. For instance, we will evaluate the fate of biochar and its efficacy as a soil amendment to reduce the leaching of agrochemicals (subobjective 1a), management practices to minimize agrochemical transport with storm runoff from low-input turf (subobjective 2a.1), and the occurrence of contaminants in urban agricultural systems and the influence of water conservation and management practices on contaminant availability (subobjective 2d). In addition, we will determine the influence of perennial cover crops and the use of different irrigation and nitrogen rates to reduce transport of nutrients with runoff and drainage from row crops subobjective 2c). Model simulations will also be used to predict nitrate loads in tile drainage from a concentrated animal feeding operations (CAFO) dairy and simulate the efficacy of alternative practices to reduce loads (subobjective 2b). In circumstances where contaminants are transported off-site with overland flow or leaching, mitigation strategies will be taken to remove contaminants from runoff and tile drainage before they reach surface waters or groundwater. Mitigation approaches include plot-scale studies to identify optimal buffer size and management of low-input turf for the removal of contaminants transported with runoff (subobjective 2a.2), while field and modeling experiments will identify the most effective bioreactor design and materials for removing nutrients from subsurface drainage water (subobjective 1b). Laboratory, field, and small watershed studies will be employed to enhance and extend the research that has been initiated to develop aspirational farming practices (ASP) for the Upper Mississippi River Basin and to compare their environmental and economic metrics against business as usual (BAU) farming practices in the region. Management practices that will be explored include maintenance of continuous living cover in sensitive locations on the landscape, and downstream or down-gradient practices that remove excess nutrients and reduce N2O emissions. Our multidisciplinary team and the interrelationship of our project subobjectives within and across these strategies will make progress towards the national goal for improved water resource security.

Progress 10/01/21 to 09/30/22

Outputs
PROGRESS REPORT Objectives (from AD-416): 1. Develop irrigation and drainage strategies in the North Central United States to protect water and soil resources a. Determine the potential of amendments to mitigate leaching and contamination of groundwater from agricultural operations. b. Identify materials and designs that will maximize contaminant removal from subsurface drainage water. 2. Identify and test innovative management practices to reduce potential adverse impacts on water quality or conserve water resources. a. Evaluate the effectiveness of low-input turf and management practices to reduce contaminant transport with runoff. b. Identify and test management practices to reduce reactive nitrogen leakage from dairy farming systems. c. Determine the impact of perenniallizing practices on the nutrient and water balances of corn/soybean systems. d. Determine the influence of management practices and water conservation strategies on water use and the occurrence and fate of contaminants in urban agriculture. 3. Conduct research as part of the LTAR network, and in concert with similar long-term, land-based research infrastructure in the U.S., use the Upper Mississippi River Basin LTAR site to improve the observational capabilities and data accessibility of the LTAR network and support research to sustain or enhance agricultural production and environmental quality in agroecosystems characteristic of the Upper Mississippi River Basin. Research and data collection are planned and implemented based on the LTAR site application and in accordance with the responsibilities outlined in the LTAR Shared Research Strategy, a living document that serves as a roadmap for LTAR implementation. Participation in the LTAR network and test innovative management practices to reduce potential adverse impacts on water quality or conserve water resources includes research and data management in support of the ARS GRACEnet and DAWG projects. Approach (from AD-416): Protecting the integrity and supply of our water resources is one of the most important issues we will face this century and therefore the foundation of our project⿿s objectives (objectives 1 and 2). Our research approach requires laboratory to field scale investigations focusing on two strategies, prevention and mitigation. With the prevention strategy we will identify and understand the fate of potential water contaminants (e.g. agrochemicals: fertilizer, pesticides; anthropogenic compounds) and develop practices to prevent or minimize the off-site transport of contaminants from their site of application or point of origin. For instance, we will evaluate the fate of biochar and its efficacy as a soil amendment to reduce the leaching of agrochemicals (subobjective 1a), management practices to minimize agrochemical transport with storm runoff from low-input turf (subobjective 2a.1), and the occurrence of contaminants in urban agricultural systems and the influence of water conservation and management practices on contaminant availability (subobjective 2d). In addition, we will determine the influence of perennial cover crops and the use of different irrigation and nitrogen rates to reduce transport of nutrients with runoff and drainage from row crops subobjective 2c). Model simulations will also be used to predict nitrate loads in tile drainage from a concentrated animal feeding operations (CAFO) dairy and simulate the efficacy of alternative practices to reduce loads (subobjective 2b). In circumstances where contaminants are transported off-site with overland flow or leaching, mitigation strategies will be taken to remove contaminants from runoff and tile drainage before they reach surface waters or groundwater. Mitigation approaches include plot-scale studies to identify optimal buffer size and management of low-input turf for the removal of contaminants transported with runoff (subobjective 2a.2), while field and modeling experiments will identify the most effective bioreactor design and materials for removing nutrients from subsurface drainage water (subobjective 1b). Laboratory, field, and small watershed studies will be employed to enhance and extend the research that has been initiated to develop aspirational farming practices (ASP) for the Upper Mississippi River Basin and to compare their environmental and economic metrics against business as usual (BAU) farming practices in the region. Management practices that will be explored include maintenance of continuous living cover in sensitive locations on the landscape, and downstream or down-gradient practices that remove excess nutrients and reduce N2O emissions. Our multidisciplinary team and the interrelationship of our project subobjectives within and across these strategies will make progress towards the national goal for improved water resource security. Analyses were completed on biochar samples that were returned from the volunteers who participated in the citizen science effort of aging biochar in their respective soils. We observed an alteration in greenhouse gas production potentials and increases in the water extractable metal species following soil exposure, particularly iron. Due the significant accumulation of iron in the aged biochar samples, we designed an additional experiment to evaluate the potential impact of dissolved iron species interacting with the biochar. We observed that the exposure of the biochar to iron solutions under laboratory conditions (with no external heating or additional water pressure applied) increased the sorption capacity of the biochar nearly 2-times, as well as increased the water-holding capacity nearly 3-times. These biochar-dissolved species interactions also provided additional physical protection against fragmentation. This research has demonstrated that the rate-limiting step for moisture interaction with biochar is driven by the phase change (first order process) and not a diffusional limitation. It was also observed during the analysis of the aged biochar samples that selection of analytical instrumentation and software signal deconvolution algorithms has profound impacts on the results for interpreting carbon electron bond configurations in aged biochar samples. Initial research data on the sorption of bicyclopyrone to a variety of soils was published, with the most striking result being the lack of correlation between soil organic matter and the soil⿿s sorption capacity for bicyclopyrone. For the first time, the fate of the allelochemical coumarin in unamended and soil amended with fresh and soil-aged biochar was determined. Biochar additions modified the soil⿿s retention capacity towards coumarin and consequently changed its degradation and leaching patterns. The aging process did not alter the sorption capacity of biochar with respect to coumarin, likely, the increase in organic matter content was the dominant factor that controlled sorption of the compound instead of the surface chemistry alterations due to soil aging. There was no consistency between dissipation, leaching and application rate, which reveals the problems relating dissipation and mobility of natural compounds in soils, since they are rapidly degraded. Biochar additions enhanced coumarin⿿s activity only at high application rates. These results supply guidance for the use of biochar amendments as a promising tool for enhancing the activity of allelochemicals. Dosing woodchips in a denitrification bioreactor with a readily available carbon source doubled nitrate removal rate from tile drainage water without increasing nitrous oxide concentrations. Research in this process showed that a three-bed bioreactor can treat tile drainage from a one- square-mile watershed, and that sedimentation can negatively impact performance. A control system designed and installed to monitor influent turbidity and close off flow during periods of high-sediment flux prevented further problems. Continuous nitrate-nitrogen sensors have been deployed and provided real-time confirmation of conservation practice effectiveness. Monitoring of a watershed adjacent to the bioreactor watershed supported preparation for a paired watershed experiment. Relationships with local producers and conservation professionals enlisted their cooperation in the paired watershed efforts. Experiments were designed to evaluate the effectiveness of low-input turf and management practices of turfgrass filter strips to mitigate contaminant transport with runoff. Replicated plots were planted with a fine fescue mixture and managed at different heights of cut. The base of each plot contained a runoff collection gutter, flume, flow meter and automated sampler to record runoff volumes and flow rates and to collect samples throughout rainfall events. A rainfall simulator provided precipitation at desired rates and durations. A manifold system delivered runoff containing sediment, nutrients from fertilizer, herbicides, fungicides, insecticides, and a conservative tracer to the top of the filter strip. Each manifold system included a mixing tank with trolling motor, pump and flow meter. Manifold samples entering the filter strip and runoff samples leaving the filter strip were collected throughout the simulated storm event and compared for contaminant content. Water samples were analyzed for specific contaminants according to published procedures or methods developed in our laboratory. Replicated evaluations across multiple years provided hundreds of samples. Analysis of inorganic compounds of interest have been completed. Chemical analysis of organic contaminants of interests are complete or nearing completion. Data analysis of contaminant loads entering and exiting the filter strips identified management practices that were most effective towards contaminant removal. Delivering the manure with center pivot irrigation during the growing season rather than with fall injection reduced tile drainage nitrate losses in a manured silage corn-alfalfa dairy cropping system. In-season application allowed reduction in rate without loss of productivity. Published research showed that alfalfa, relative to corn silage, reduced losses of nitrate-nitrogen and sediment in tile drainage. An environmental assessment of U.S. dairy farms, which included our input on crop, feed, management practices, and water impacts in the Upper Midwest, indicated the loss of reactive nitrogen is a significant industry challenge, with water-borne losses critical in our region. Field phosphorus (P) budgets from this research, via inclusion in a national P budget database, provided context for understanding cropping systems⿿ contributions to phosphorus-related water quality problems. We conducted intensive soil sampling of our Long-Term Agroecosystem Research (LTAR) ⿿aspirational⿝ and ⿿business as usual⿝ fields with cores to 75 cm depth at 64 locations in each field. These will be compared to samples taken at the start of the experiment to document changes due to differences in management. In related work, an experiment was conducted in the aspirational system to determine the spatial distribution of corn and clover roots, and to determine the fate of nitrogen released by decomposing clover. We found virtually no corn roots in the interrow region, indicating that very little of the clover-derived N was taken up by the corn. We also found higher N2O emission from the interrow than from the row. In the Water Parcel Tracking project, we mapped in-stream nitrate concentrations in the High Island Creek watershed on multiple occasions, using our inflatable raft-based platform. Overlaying the nitrate maps with maps of land use and funded conservation practices is now being conducted to estimate the effectiveness of those practices. Community gardens were visited for observation of management practices, and samples were collected in the Twin Cities metropolitan area. This provided insight on practices and inputs associated with urban agriculture. Replicated plots were established to provide scientific assessments of contaminant transport with leachate, crop growth, harvest yields, and cost of urban food production in conventional, alternative, and innovative urban agricultural systems. Raised bed plots were constructed on stainless steel trays that guided water leaching from the plant matrix to flumes for sample collection. Selected crops included vegetables that represent harvest of fruits, roots, and leafy greens. Moisture content and temperature of planting matrix (soil, straw bale, or layered no-dig) was periodically measured before and after natural or simulated precipitation. Subsamples of raised bed inputs and end-of- season planting matrix were analyzed and compared. Concentrations of nitrogen and phosphorus were measured in water samples leached from each raised bed to assess off-site transport of excess nutrients. Measure of leaf chlorophyll, plant nitrogen content, and harvest yields were also compared between identical crops grown in the three urban agricultural systems. These studies showed the influence of management practices on the productivity, cost, and environmental contaminant transport from the urban agricultural systems evaluated. Research was conducted as part of the LTAR network, representing the Upper Mississippi River Basin site. Collection of grab surface water samples and deployment of polar organic chemical integrative samplers were conducted for multiple years as part of a cooperative effort with other LTAR locations, led by the Lower Chesapeake Bay site. Sample collection and analyses are nearly complete. Data evaluation is ongoing. The project goal is to track the transport and fate of nitrogen in agricultural watersheds. Additional LTAR related research involved development of new methods to map nitrate concentrations in watersheds and related spatial differences to edge-of-field conservation practices, use of a stable isotope mass spectrometer for improved tracing of carbon cycling and mechanistic level nitrogen cycling, and ⿿aspirational⿝ and ⿿business as usual⿝ research (see 2c). Scientists from St. Paul, Minnesota, are active participants in LTAR working groups including Croplands, Drainage, Eddy Covariance, Non-CO2 Greenhouse Gases, Resilience, Soil, Water Quality, and Water Quantity. This is the final report for this project which terminated on May 21, 2022 and is replaced by project, 5062-12130-008-00D, ⿿Developing and Evaluating Strategies to Protect and conserve Water and Environmental Resources While Maintaining Productivity in Agronomic Systems⿝ that was certified by OSQR on May 10, 2022. ACCOMPLISHMENTS 01 Iron and biochar interactions increases chemical sorption capacity of biochar. There is a growing issue of antibiotic chemicals being detected in the environment. ARS researchers in St. Paul, Minnesota examined the potential use of biochar to reduce the presence and availability of antibiotics in agricultural soils, as well as simple pretreatment of the biochar with iron salt solutions to increase biochar⿿s removal effectiveness. They observed that modifying the biochar with an iron-salt solution increases the observed antibiotic sorption capacity of the biochar nearly 2-times. Additionally, adding the iron-treated biochar to the soil system at 2% (w/w) did increase the half-life (the time for 50% of the antibiotic to be removed from the water) from 4 to 6.4 days. These results will assist scientists and engineers, supplying guidance for the influence of biochar additions in mitigating antibiotics and other agrochemicals in the soil system. 02 Fine fescue vegetative filter strips mitigate herbicide transport in runoff. Herbicides are a useful tool for controlling weeds in crops and on managed landscapes. However, they may be transported from their site of application with runoff to locations that may impact sensitive non- target organisms. ARS researchers at St. Paul, Minnesota, conducted studies to evaluate the ability of a fine fescue mixture vegetative filter strip to reduce quantities of herbicides transported with surface runoff. Measurement of herbicides (dicamba, mecoprop-p and 2,4- D) in runoff entering and exiting a 50-ft vegetative filter strip revealed the fine fescue turfgrass mixture removed 67 to 99% of the herbicides that were transported with runoff. This research data is important to land managers to help support decisions toward enhanced environmental stewardship and to scientists for modeling larger scale impacts of implementing these mitigation measures. 03 A living mulch system enhances soil infiltration and reduces soil erosion in row crops. Corn and soybean farmers are encouraged to use winter cover crops for a variety of reasons, but it is challenging and expensive to replant them every fall. Perennial living mulches have been proposed as way to get the benefits of cover crops while only having to plant them once. ARS researchers at St. Paul, Minnesota, completed a 5-year project examining the long-term environmental impact of a new farming practice ⿿ growing corn and soybeans in a perennial living mulch of kura clover. This research was conducted at Rosemount Minnesota and Arlington Wisconsin. After 5 years of planting row crops in both treatments, all of the soil property measurements were repeated. While no differences were found in many soil properties, there were large differences in water infiltration rates ⿿ which were 10-19 times higher in the living mulch system compared to the conventional system. In a related experiment, storm runoff was measured on sloped plots with both systems, and the living mulch system reduced erosive soil loss by 93% compared to the conventional system. These results show that growing corn in a perennial living mulch is a promising management practice for producers challenged by either poor water infiltration or soil erosion. 04 Alfalfa reduces nitrate and phosphorus loads in tile drainage water from manured fields. Dairy products provide needed protein at a reasonable price, yet manure management practices on large, concentrated dairies can negatively impact natural water system health. ARS researchers in St. Paul and Morris, Minnesota, monitored flow rate, and nitrate, phosphorus, and sediment concentrations in tile drainage water from manured silage corn and alfalfa fields on a modern dairy. Alfalfa substantially reduced weekly nitrate and phosphorus loads and annual sediment loads compared to silage corn. These results indicate that surface and groundwater quality may be improved by increasing alfalfa acreage with respect to silage corn in dairy production systems. This research underscores the importance of perennials such as alfalfa for dairy producers to protect water resources.

Impacts
(N/A)

Publications

Spokas, K.A., Bogner, J., Corcoran, M. 2021. Modeling landfill CH4 emissions: CALMIM international field validation, using CALMIM to simulate management strategies, current and future climate scenarios. Elementa: Science of the Anthropocene. 9(1). Article 00050. https://doi.org/10.1525/ elementa.2020.00050.
Gamble, J.D., Baker, J.M., Dalzell, B.J., Wente, C.D., Feyereisen, G.W. 2022. Ecohydrology of irrigated silage maize and alfalfa production systems in the Upper Midwest US. Agricultural Water Management. 267. Article 107612. https://doi.org/10.1016/j.agwat.2022.107612.
Ferrari, F., Thomazini, A., Pereira, A., Spokas, K.A., Schaefer, C. 2022. Potential greenhouse gases emissions by different plant communities in maritime Antarctica. Annals of the Brazilian Academy of Science. 94(4). https://doi.org/10.1590/0001-3765202220210602.
Feyereisen, G.W., Hay, C.H., Christianson, R.D., Helmers, M.J. 2022. Eating the metaphorical elephant: Meeting nitrogen reduction goals in Upper Mississippi River Basin states. Journal of the ASABE. 65(3):621-631. https://doi.org/10.13031/ja.14887.
Goebel, K.M., Davros, N.M., Andersen, D.E., Rice, P.J. 2022. Tallgrass prairie wildlife exposure to spray drift from commonly used soybean insecticides in Midwestern USA. Science of the Total Environment. 818. Article 151745. https://doi.org/10.1016/j.scitotenv.2021.151745.
Lentz, R.D., Ippolito, J.A., Spokas, K.A. 2022. Does turbulent-flow conditioning of irrigation water influence soil chemical processes: II. Long-term soil and crop study. Communications in Soil Science and Plant Analysis. 53(5):636-650. https://doi.org/10.1080/00103624.2021.2017963.
Baker, J.M., Feyereisen, G.W., Albrecht, K.A., Gamble, J.D. 2022. A perennial living mulch substantially increases infiltration in row crop systems. Journal of Soil and Water Conservation. 77(2):212-220. https:// doi.org/10.2489/jswc.2022.00080.
Ducey, T.F., Sigua, G.C., Novak, J.M., Ippolito, J.A., Spokas, K.A., Johnson, M.G. 2021. Microbial response to phytostabilization in mining impacted soils using maize in conjunction with biochar and compost. Microorganisms. 9(12), Article 2545. https://doi.org/10.3390/ microorganisms9122545.
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.

Progress 10/01/20 to 09/30/21

Outputs
PROGRESS REPORT Objectives (from AD-416): 1. Develop irrigation and drainage strategies in the North Central United States to protect water and soil resources a. Determine the potential of amendments to mitigate leaching and contamination of groundwater from agricultural operations. b. Identify materials and designs that will maximize contaminant removal from subsurface drainage water. 2. Identify and test innovative management practices to reduce potential adverse impacts on water quality or conserve water resources. a. Evaluate the effectiveness of low-input turf and management practices to reduce contaminant transport with runoff. b. Identify and test management practices to reduce reactive nitrogen leakage from dairy farming systems. c. Determine the impact of perenniallizing practices on the nutrient and water balances of corn/soybean systems. d. Determine the influence of management practices and water conservation strategies on water use and the occurrence and fate of contaminants in urban agriculture. 3. Conduct research as part of the LTAR network, and in concert with similar long-term, land-based research infrastructure in the U.S., use the Upper Mississippi River Basin LTAR site to improve the observational capabilities and data accessibility of the LTAR network and support research to sustain or enhance agricultural production and environmental quality in agroecosystems characteristic of the Upper Mississippi River Basin. Research and data collection are planned and implemented based on the LTAR site application and in accordance with the responsibilities outlined in the LTAR Shared Research Strategy, a living document that serves as a roadmap for LTAR implementation. Participation in the LTAR network and test innovative management practices to reduce potential adverse impacts on water quality or conserve water resources includes research and data management in support of the ARS GRACEnet and DAWG projects. Approach (from AD-416): Protecting the integrity and supply of our water resources is one of the most important issues we will face this century and therefore the foundation of our project⿿s objectives (objectives 1 and 2). Our research approach requires laboratory to field scale investigations focusing on two strategies, prevention and mitigation. With the prevention strategy we will identify and understand the fate of potential water contaminants (e.g. agrochemicals: fertilizer, pesticides; anthropogenic compounds) and develop practices to prevent or minimize the off-site transport of contaminants from their site of application or point of origin. For instance, we will evaluate the fate of biochar and its efficacy as a soil amendment to reduce the leaching of agrochemicals (subobjective 1a), management practices to minimize agrochemical transport with storm runoff from low-input turf (subobjective 2a.1), and the occurrence of contaminants in urban agricultural systems and the influence of water conservation and management practices on contaminant availability (subobjective 2d). In addition, we will determine the influence of perennial cover crops and the use of different irrigation and nitrogen rates to reduce transport of nutrients with runoff and drainage from row crops subobjective 2c). Model simulations will also be used to predict nitrate loads in tile drainage from a concentrated animal feeding operations (CAFO) dairy and simulate the efficacy of alternative practices to reduce loads (subobjective 2b). In circumstances where contaminants are transported off-site with overland flow or leaching, mitigation strategies will be taken to remove contaminants from runoff and tile drainage before they reach surface waters or groundwater. Mitigation approaches include plot-scale studies to identify optimal buffer size and management of low-input turf for the removal of contaminants transported with runoff (subobjective 2a.2), while field and modeling experiments will identify the most effective bioreactor design and materials for removing nutrients from subsurface drainage water (subobjective 1b). Laboratory, field, and small watershed studies will be employed to enhance and extend the research that has been initiated to develop aspirational farming practices (ASP) for the Upper Mississippi River Basin and to compare their environmental and economic metrics against business as usual (BAU) farming practices in the region. Management practices that will be explored include maintenance of continuous living cover in sensitive locations on the landscape, and downstream or down-gradient practices that remove excess nutrients and reduce N2O emissions. Our multidisciplinary team and the interrelationship of our project subobjectives within and across these strategies will make progress towards the national goal for improved water resource security. Subobjective 1a. Returned biochar samples have been analyzed for extractable metals as well as total carbon to nitrogen (C-N) ratio. This data is being utilized with the soil composition data to examine for correlations across multiple locations for biochar weathering characteristics. Additionally, statistical analyses are being conducted to determine if there are any feedstock/pyrolysis temperature dependencies on the biochar oxidation. Subobjective 1a. A control system has been developed to optimize relative humidity (RH) control during the biochar moisture sorption evaluation. This system was necessary to obtain more precise data on the rate of water sorption on biochar samples at defined relative humidity contents in the laboratory incubator. This system utilizes an Arduino microcontroller, which then controls air pumps which either moistens (through a water atomizer) or dries (through a desiccant trap) the air within the incubator. This system has been able to control the RH more precisely in the chamber (± 5%), which is superior to the control achieved with saturated salt solutions. Subobjective 1a. A manuscript was published detailing the selection of analytical instrumentation and software curve deconvolution algorithms on the results for carbon electron bond configurations in aged biochar samples. Additionally, the initial research data on the sorption of bicyclopyrone to a variety of soils was published this year. The most striking result of this sorption study was the lack of correlation with soil organic matter and the soil⿿s sorption capacity for bicyclopyrone. Subobjective 1b. Addition of a readily available carbon source to woodchip denitrifying bioreactors at four-fold flow rates doubled the nitrate-nitrogen (N) removal rate without increasing nitrous oxide (N2O) concentrations in the effluent. Follow-up experimentation is evaluating nitrate-N removal and N2O production rates for media with various C-N ratios and periodic aeration. The large three-bed bioreactor was re- charged with new woodchips and has been instrumented with high-resolution nitrate-N concentration sensors. A system to sense influent turbidity level and control flow has been excluding sediment from entering the bioreactors when sediment increases in tile flow. A watershed adjacent to the bioreactor watershed has been instrumented. Data from the watersheds, which includes high-resolution nitrate-N concentration, are being shared with the producers, who are interested in seeing the impacts of their application practices on water quality. Subobjective 2a. Experiments designed to evaluate the effectiveness of low-input turf and management practices of turfgrass filter strips to reduce contaminant transport with runoff were continued. Modifications to sample extraction and analysis methods were performed to accommodate changes in instrumentation and updated software. Extraction of contaminants of interest from the runoff and manifold water samples and their analytical quantification are ongoing. Subobjective 2b. An environmental assessment of U.S. dairy farms indicated that loss of reactive nitrogen is a significant industry challenge, with two-thirds of the losses in the form of ammonia. Dairy ammonia losses represent roughly one-fifth to one-fourth of the national ammonia emission inventories. The assessment was based on whole-farm modeling, led by ARS researchers at University Park, Pennsylvania, with our input on feed, crop, and manure management practices in the Midwest and input from other ARS units involved in the Dairy Agroecosystem Working Group (DAWG). Subobjective 2c. A new project has been initiated, funded by USDA-FSA (Farm Service Agency), to develop a new method, Water Parcel Tracking, for mapping how key water quality parameters can change as water flows downstream. In particular, we apply this approach to map nitrate concentration in small watersheds. These maps will be overlaid with maps of FSA-funded conservation practices to evaluate their effectiveness. Two graduate students have been hired to work on the project, and mapping has begun in two watersheds. Subobjective 2d. Collection of soil samples from vacant lots continues, as well as efforts to identify and sample additional locations where urban food production is anticipated. Observation of established community gardens continues in order to identify currently utilized management practices and urban agricultural inputs. Refinement of extraction and analysis methodologies and progress toward sample extraction and analysis are ongoing. The location of plots for evaluation of conventional and innovative urban agricultural systems were relocated and data and sample collection and analysis are ongoing. Objective 3. Deployment and collection of passive samplers and collection of grab water samples continued for an additional year towards a cooperative effort with several other Long-Term Agroecosystem Research (LTAR) locations, led by the Lower Chesapeake Bay LTAR, to track the transport and fate of nitrogen in agricultural watersheds. Record of Any Impact of Maximized Teleworking Requirement: The maximized telework posture due to COVID-19 enabled one ARS scientist to analyze backlogs of data and to progress in first-author publishing. This scientist contracted COVID-19 and suffered from PASC COVID (post- acute sequelae SARS-CoV-2) for five months. One of the symptoms of PASC COVID is activity intolerance, which would have kept the scientist from commuting to their duty station and maintaining the rigors of a ⿿normal⿝ workday under non-pandemic conditions. The maximum telework posture enabled this scientist to work 6 to 7 hours per day, as health permitted, thus allowing them to maintain some progress as opposed to falling behind on research objectives. Due to the global pivoting to teleworking and the conversion of meetings and workshops to video conferencing (i.e., Zoom), this allowed for new and unplanned collaborations to be fostered during the pandemic. One example of this was the new collaboration formed with University of Manitoba (Winnipeg) and University of Saskatchewan (Saskatoon) on the reliability of advanced analytical instrumentation in determining the functional group distribution on field-aged biochars. Social distancing requirements in laboratories due to COVID-19 made it more difficult to train new students and workers. Maximized teleworking and travel restrictions resulted in a virtual Long- Term Agroecosystem Research (LTAR) annual meeting, which enabled a greater number of scientists to participate and enhanced new collaborative efforts. ACCOMPLISHMENTS 01 Soil sorption of bicyclopyrone is not controlled by organic matter content. Bicyclopyrone is a new herbicide that targets a specific enzyme reaction in plants and is particularly used for control of weeds that have become resistant to other herbicides. However, there is little known about the behavior of bicyclopyrone in the soil system, which is needed to determine its fate and transport. Therefore, ARS researchers at St. Paul, Minnesota and Brookings, South Dakota evaluated its binding across a wide collection of soils (25 total) that ranged in chemical properties. Our data demonstrated that there was no correlation between any of the soil properties measured (including organic matter) and the soil sorption capacities. This lack of correlation complicates prediction of risk of carryover and water contamination by bicyclopyrone. These results are significant to assist scientists, engineers, farmers, as well as provide evidence that the measured soil properties do not control the binding of bicyclopyrone in the environment; therefore, other potential regulating factors that may mitigate risk need to be investigated. 02 Turfgrass filter strips remove nitrogen from runoff, potentially reducing algal blooms. Fertilizer provides nutrients essential for plant growth. However, nitrate and ammonium, two forms of nitrogen found in chemical fertilizer, are very water soluble and readily transported with runoff from areas of application to surrounding surface waters. Excess nitrogen in surface waters can lead to aquatic plant and algal blooms that block light and consume dissolved oxygen as they degrade, leading to areas of hypoxia and fish kills. ARS researchers at St. Paul, Minnesota, conducted studies to evaluate the ability of a fine fescue mixture vegetative filter strip to reduce quantities of nitrate nitrogen and ammonium nitrogen transported with surface runoff. Measurement of nutrient concentrations in runoff at the entrance and exit of 50-ft vegetative filter strips revealed a 40 to 89% removal of nitrate nitrogen and a 77 to 98% removal of ammonium nitrogen depending on the mow height of the fine fescue turfgrass mixture. This research data is important to land managers to help support decisions toward enhanced environmental stewardship and to scientists for modeling larger scale impacts of implementing these mitigation measures.

Impacts
(N/A)

Publications

Ezzati, G., Healy, M.G., Christianson, L.E., Daly, K., Fenton, O., Feyereisen, G.W., Thornton, S., Callery, O. 2020. Use of rapid small-scale column tests for simultaneous prediction of phosphorus and nitrogen retention in large-scale filters. Journal of Water Process Engineering. 37. Article 101473. https://doi.org/10.1016/j.jwpe.2020.101473.
Christianson, L.E., Cooke, R.A., Hay, C.H., Helmers, M.J., Feyereisen, G.W. , Ranaivoson, A.Z., McMaine, J.T., McDaniel, R., Rosen, T.R., Pluer, W.T., Schipper, L.A., Dougherty, H., Robinson, R.J., Layden, I.A., Irvine-Brown, S.M., Manca, F., Dhaese, K., Nelissen, V., Von Ahnen, M. 2021. Effectiveness of denitrifying bioreactors on water pollutant reduction from agricultural areas. Transactions of the ASABE. 64(2):641-658. https:// doi.org/10.13031/trans.14011.
Venterea, R.T., Clough, T.J., Coulter, J.A., Souza, E.F., Breuillin- Sessoms, F., Spokas, K.A., Sadowsky, M.J., Gupta, S.K., Bronson, K.F. 2021. Temperature alters dicyandiamide (DCD) efficacy for multiple reactive nitrogen species in urea-amended soils: Experiments and modeling. Soil Biology and Biochemistry. 160. Article 108341. https://doi.org/10.1016/j. soilbio.2021.108341.
Ao, S., Russelle, M.P., Feyereisen, G.W., Varga, T., Coulter, J.A. 2020. Maize hybrid response to sustained moderate drought stress reveals clues for improved management. Agronomy. 10(9). Article 1374. https://doi.org/10. 3390/agronomy10091374.
Feyereisen, G.W., Spokas, K.A., Strock, J.S., Mulla, D.J., Ranaivoson, A.Z. , Coulter, J.A. 2020. Nitrate removal and nitrous oxide production from upflow and downflow column woodchip bioreactors. Agricultural and Environmental Letters. 5(1). Article e20024. https://doi.org/10.1002/ael2. 20024.
Gamiz, B., Lopez-Cabeza, R., Velarde, P., Spokas, K.A., Cox, L. 2020. Biochar changes the bioavailability and bioefficacy of the allelochemical coumarin in agricultural soils. Pest Management Science. 77(2):834-843. https://doi.org/10.1002/ps.6086.
Ippolito, J.A., Cui, L., Kammann, C., Wrage-Monnig, N., Estavillo, J.M., Fuertes-Mendizabal, T., Cayuela, M., Sigua, G.C., Novak, J.M., Spokas, K.A. , Borchard, N. 2020. Feedstock choice, pyrolysis temperature and type influence biochar characteristics: a comprehensive meta-data analysis review. Biochar. 2:421-438. https://doi.org/10.1007/s42773-020-00067-x.
Spokas, K.A., Schneider, S.K., Gamiz, B., Hall, K., Chen, W. 2021. Sorption and desorption of bicyclopyrone on soils. Agricultural and Environmental Letters. 5(1). Article e20039. https://doi.org/10.1002/ael2. 20039.
Munira, S., Dynes, J.J., Islam, M., Khan, F., Adesanya, T., Regier, T.Z., Spokas, K.A., Farenhorst, A. 2021. Relative proportions of organic carbon functional groups in biochars as influenced by spectral data collection and processing. Chemosphere. 283. Article 131023. https://doi.org/10.1016/ j.chemosphere.2021.131023.
Souza, E., Rosen, C., Venterea, R.T. 2021. Co-application of DMPSA and NBPT with urea mitigates both nitrous oxide emissions and nitrate leaching during irrigated potato production. Environmental Pollution. 284. Article 117124. https://doi.org/10.1016/j.envpol.2021.117124.
Schaefer, A., Werning, K., Hoover, N., Tschirner, U., Feyereisen, G.W., Moorman, T.B., Howe, A.C., Soupir, M.L. 2021. Impact of flow on woodchip properties and subsidence in denitrifying bioreactors. Agrosystems, Geosciences & Environment. 4(1). Article e20149. https://doi.org/10.1002/ agg2.20149.
Hansen, A.T., Campbell, T., Cho, S., Czuba, J.A., Dalzell, B.J., Dolph, C. L., Hawthorne, P.L., Rabotyagov, S., Lang, Z., Kumarasamy, K., Belmont, P., Finlay, J.C., Foufoula, E., Gran, K.B., Kling, C., Wilcock, P. 2021. Integrated assessment modeling reveals near-channel management as cost- effective to improve water quality in agricultural watersheds. Proceedings of the National Academy of Sciences (PNAS). 118(28). Article e2024912118. https://doi.org/10.1073/pnas.2024912118.
Rotz, C.A., Stout, R.C., Leytem, A.B., Feyereisen, G.W., Waldrip, H., Thoma, G., Holly, M., Bjorneberg, D.L., Baker, J.M., Vadas, P.A., Kleinman, P.J. 2021. Environmental assessment of United States dairy farms. Journal of Cleaner Production. 315. Article 128153. https://doi.org/10.1016/j. jclepro.2021.128153.
Ducey, T.F., Novak, J.M., Sigua, G.C., Ippolito, J.A., Rushmiller, H.C., Watts, D.W., Trippe, K.M., Spokas, K.A., Stone, K.C., Johnson, M.G. 2021. Microbial response to designer biochar and compost treatments for mining impacted soils. Biochar. 3:299-314. https://doi.org/10.1007/s42773-021- 00093-3.
Trippe, K.M., Manning, V., Reardon, C.L., Klein, A.M., Weidman, C.S., Ducey, T.F., Novak, J.M., Watts, D.W., Rushmiller, H.C., Spokas, K.A., Ippolito, J.A., Johnson, M.G. 2021. Phytostabilization of acidic mine tailings with biochar, biosolids, lime, and locally-sourced microbial inoculum: Do amendment mixtures influence plant growth, tailing chemistry, and microbial composition? Applied Soil Ecology. 165. Article 103962. https://doi.org/10.1016/j.apsoil.2021.103962.
Weyers, S.L., Gesch, R.W., Forella, F., Eberle, C., Thom, M.D., Matthees, H.L., Ott, M., Feyereisen, G.W., Strock, J.S. 2021. Surface runoff and nutrient dynamics in cover crop-soybean systems in the Upper Midwest. Journal of Environmental Quality. 50(1):158-171. https://doi.org/10.1002/ jeq2.20135.

Progress 10/01/19 to 09/30/20

Outputs
Progress Report Objectives (from AD-416): 1. Develop irrigation and drainage strategies in the North Central United States to protect water and soil resources a. Determine the potential of amendments to mitigate leaching and contamination of groundwater from agricultural operations. b. Identify materials and designs that will maximize contaminant removal from subsurface drainage water. 2. Identify and test innovative management practices to reduce potential adverse impacts on water quality or conserve water resources. a. Evaluate the effectiveness of low-input turf and management practices to reduce contaminant transport with runoff. b. Identify and test management practices to reduce reactive nitrogen leakage from dairy farming systems. c. Determine the impact of perenniallizing practices on the nutrient and water balances of corn/soybean systems. d. Determine the influence of management practices and water conservation strategies on water use and the occurrence and fate of contaminants in urban agriculture. 3. Conduct research as part of the LTAR network, and in concert with similar long-term, land-based research infrastructure in the U.S., use the Upper Mississippi River Basin LTAR site to improve the observational capabilities and data accessibility of the LTAR network and support research to sustain or enhance agricultural production and environmental quality in agroecosystems characteristic of the Upper Mississippi River Basin. Research and data collection are planned and implemented based on the LTAR site application and in accordance with the responsibilities outlined in the LTAR Shared Research Strategy, a living document that serves as a roadmap for LTAR implementation. Participation in the LTAR network and test innovative management practices to reduce potential adverse impacts on water quality or conserve water resources includes research and data management in support of the ARS GRACEnet and DAWG projects. Approach (from AD-416): Protecting the integrity and supply of our water resources is one of the most important issues we will face this century and therefore the foundation of our project⿿s objectives (objectives 1 and 2). Our research approach requires laboratory to field scale investigations focusing on two strategies, prevention and mitigation. With the prevention strategy we will identify and understand the fate of potential water contaminants (e.g. agrochemicals: fertilizer, pesticides; anthropogenic compounds) and develop practices to prevent or minimize the off-site transport of contaminants from their site of application or point of origin. For instance, we will evaluate the fate of biochar and its efficacy as a soil amendment to reduce the leaching of agrochemicals (subobjective 1a), management practices to minimize agrochemical transport with storm runoff from low-input turf (subobjective 2a.1), and the occurrence of contaminants in urban agricultural systems and the influence of water conservation and management practices on contaminant availability (subobjective 2d). In addition, we will determine the influence of perennial cover crops and the use of different irrigation and nitrogen rates to reduce transport of nutrients with runoff and drainage from row crops subobjective 2c). Model simulations will also be used to predict nitrate loads in tile drainage from a concentrated animal feeding operations (CAFO) dairy and simulate the efficacy of alternative practices to reduce loads (subobjective 2b). In circumstances where contaminants are transported off-site with overland flow or leaching, mitigation strategies will be taken to remove contaminants from runoff and tile drainage before they reach surface waters or groundwater. Mitigation approaches include plot-scale studies to identify optimal buffer size and management of low-input turf for the removal of contaminants transported with runoff (subobjective 2a.2), while field and modeling experiments will identify the most effective bioreactor design and materials for removing nutrients from subsurface drainage water (subobjective 1b). Laboratory, field, and small watershed studies will be employed to enhance and extend the research that has been initiated to develop aspirational farming practices (ASP) for the Upper Mississippi River Basin and to compare their environmental and economic metrics against business as usual (BAU) farming practices in the region. Management practices that will be explored include maintenance of continuous living cover in sensitive locations on the landscape, and downstream or down-gradient practices that remove excess nutrients and reduce N2O emissions. Our multidisciplinary team and the interrelationship of our project subobjectives within and across these strategies will make progress towards the national goal for improved water resource security. Laboratory analyses on the initial samples from the biochar aging citizen science experiment are continuing. Currently, the samples are being analyzed for the alteration in greenhouse gas production potentials and the alteration in sorbed cation species. Customized R-scripts have been developed to aid in the automation of data processing for the samples returned from the citizen science project. Data from four sites have been processed to date. All 12 aged biochar samples have been processed for water extractable metal content, but the samples are still waiting for instrument analysis. These aged biochar samples will also be analyzed by stable isotope mass spectrometry for alterations in the isotopic signatures of carbon and nitrogen for potential insights into the compositional alterations from soil aging. Additionally, research continued the development of Arduino based balance systems for monitoring the impact of biochar and water vapor. These systems can be enclosed in environments of known temperature, relative humidity and carbon dioxide concentrations, so the kinetics of the moisture sorption process can be determined on fresh and aged biochar samples. This work has demonstrated that the rate limiting step for moisture interaction with biochar is driven by the phase change (first order process) and not a diffusional limitation. For the first time, the fate of the allelochemical coumarin in unamended and soil amended with fresh and soil-aged biochar was determined. Biochar additions modified the soil⿿s retention capacity towards coumarin and consequently, changed its degradation and leaching patterns. The aging process did not alter the sorption capacity of biochar with respect to coumarin, likely, the increase in organic matter content was the dominant factor that controlled sorption of the compound instead of the surface chemistry alterations due to soil aging. There was no consistency between dissipation, leaching and application rate, which reveals the problems relating dissipation and mobility of natural compounds in soils, since they are rapidly degraded. Biochar additions enhanced coumarin⿿s activity only at high application rates. These results supply guidance for the use of biochar amendments as a promising tool for enhancing the activity of allelochemicals. The laboratory experiment to improve nutrient removal in denitrifying bioreactors by adding a readily available carbon source has been completed and summarized in a peer-reviewed journal article. The work showed that, by adding an acetate carbon source, flow through bioreactors can be increased by 3- to 4-fold without producing additional nitrous oxide. The three-bed bioreactor has been offline waiting planned renovation. During this time, watershed parameters continued to be monitored; data have been made available to producers and local conservation agency personnel to build awareness of management and weather impacts on water quality outcomes. Producers have been engaged several times to establish a working group willing to coordinate management change at a scale at which discernible improvement can be expected to be seen. To this end, permission has been obtained to deploy instrumentation on a neighboring, paired watershed to the one previously mentioned. Experiments are underway to provide an additional field season of data evaluating the effectiveness of low-input turf and management practices to reduce contaminant transport with runoff. Standard annual repairs were made to the experimental plots including the repositioning and testing of the runoff collection system and testing of the rainfall simulator and run-on manifold. Plots planted with a low-input fine fescue turfgrass are being managed as either a golf course fairway or residential lawn. Evaluation of flow data and water sample collection, extraction and analysis are ongoing. Modeling (Integrated Farming System Model) of reactive nitrogen losses from representative dairy farms for ten Midwestern states is progressing in collaboration with ARS researchers in University Park, Pennsylvania. Model inputs related to feed, crop, and manure management practices are being refined with input from researchers and extension personnel in each state. Collaboration with other ARS researchers in the Dairy Agroecosystem Working Group on other dairy-related environmental studies continues. We analyzed multiple years of evapotranspiration (ET) data from our Long- Term Agroecosystem Research (LTAR) fields and our native prairie system. The data show that the order of annual ET use, from greatest to least, is living mulch system > conventional corn/soy > native prairie. We initiated a new experiment in the living mulch system to determine impacts of tillage and suppression management on soil nitrogen (N) cycling. Implementation of living mulch technology in the corn/soybean rotation will result in reduced offsite nitrate loss through higher ET, less drainage, less runoff, and more effective N use. Collection of soil samples from vacant lots continues, as well as efforts to identify and sample additional locations where urban food production is anticipated. Observation of established community gardens continues in order to identify currently utilized management practices and urban agricultural inputs. Testing and refinement of extraction and analysis methodologies are ongoing. These efforts will identify the occurrence of contaminants in urban agriculture and potential sources that will lead to the development of management practices to mitigate concerns and provide guidelines for healthy food production in areas with anthropogenic contaminants. A stable isotope mass spectrometer was purchased which will be used for both the improved analytical methodology for tracing carbon cycling (particularly envisioned to aid LTAR research efforts) as well as add improved mechanistic level research for nitrogen cycling. The stable isotope mass spectrometer was installed in the laboratory just prior to the COVID-19 outbreak. Two experiments initiated in 2019 were continued in 2020. The first is a cooperative effort with several other LTAR locations, led by the Lower Chesapeake Bay LTAR, to determine the lag time of watersheds with a novel technique. The second developed new methods to map nitrate concentrations in watersheds and related spatial differences to edge-of-field conservation practices. Accomplishments 01 Use of biochar to improve cation exchange capacity of soils. The ability to increase the nutrient holding capacity of soils is an important mechanism to improve the fertility of low productivity soils, particularly those located in humid and tropical regions. ARS researchers at Saint Paul, Minnesota, completed the laboratory experiments examining the impact of three different feedstocks that were used for biochar production at three different temperatures (350, 450, and 750 C). Feedstock, pyrolysis temperature, and application rate were key factors controlling the cation exchange capacity (CEC) of biochar-amended soils and increasing the fertility of the two Oxisols used in this study. High-ash biochar produced at low pyrolysis temperatures (<450 C) increases the soil CEC to the greatest extent. Interestingly, increases in soil CEC from biochar additions correlated with soil pH rather than with soil carbon. CEC of the amended soils can be estimated from the biochar CEC, rate, liming value, and the extent of soil acidity neutralization. In this short-term incubation study, aging is a minor factor controlling CEC of the biochar-treated soils. Overall, this study provides results that guide selecting biochars for specific agronomic and environmental applications, such as improving soil CEC. 02 Continental scale analysis of manure sources and sinks. Nutrient recycling is fundamental to sustainable agricultural systems. Few mechanisms exist, however, to ensure that surplus manure nutrients from confined animal feeding operations are transported for use in nutrient- deficient croplands. As a result, surplus manure nutrients concentrate in locations where they can threaten environmental health and devalue manure as a fertilizer resource. This study advances the concept of the ⿿manureshed⿝ ⿿ the geographic area surrounding one or more livestock operations where excess manure nutrients can be recycled for agricultural production. ARS scientists at Saint Paul, Minnesota, classified the 3109 counties of the contiguous United States by their capacity to either supply manure phosphorus (P) and nitrogen (N) (⿿sources⿝) or assimilate and remove excess P and N via crops (⿿sinks⿝). Manuresheds with source areas dominated by various combinations of confined hog, poultry, dairy, and beef industries differed in the transport distances needed to assimilate excess manure P (from 147 ± 51 km for a beef dominated manureshed to 368 ±140 km for a poultry dominated manureshed), highlighting the need for systems-level strategies to promote manure nutrient recycling that operate across local, county, regional and national scales.

Impacts
(N/A)

Publications

Jilling, A., Kane, D., Williams, A., Yannarell, A., Davis, A., Jordan, N., Koide, R., Mortensen, D., Smith, R., Snapp, S., Spokas, K.A., Grandy, S. 2019. Rapid and distinct responses of particulate and mineral-associated organic nitrogen to conservation tillage and cover crops. Geoderma. 359.
Griffis, T.J., Hu, C., Baker, J.M., Wood, J.D., Millet, D.B., Erickson, M. D., Yu, Z., Deventer, J.M., Winker, C.D., Chen, Z. 2019. Tall tower ammonia observations and emission estimates in the U.S. Midwest. Journal of Geophysical Research-Biogeosciences. 124(11):3432-3447.
Hu, C., Griffis, T.J., Baker, J.M., Wood, J.D., Millet, D.B., Yu, Z., Lee, X. 2019. Modeling the sources and transport processes during extreme ammonia episodes in the U.S. Corn Belt. Journal of Geophysical Research Atmospheres. 125(2):e2019JD031207.
Anderson, E., Jang, J., Venterea, R.T., Feyereisen, G.W., Ishii, S. 2020. Isolation and characterization of denitrifiers from woodchip bioreactors for bioaugmentation application. Journal of Applied Microbiology.
Baffaut, C., Baker, J.M., Biederman, J.A., Bosch, D.D., Brooks, E.S., Buda, A.R., Demaria, E.M., Elias, E.H., Flerchinger, G.N., Goodrich, D.C., Hamilton, S.K., Hardegree, S.P., Harmel, R.D., Hoover, D.L., King, K.W., Kleinman, P.J., Liebig, M.A., McCarty, G.W., Moglen, G.E., Moorman, T.B., Moriasi, D.N., Okalebo, J., Pierson Jr, F.B., Russell, E.S., Saliendra, N. Z., Saha, A.K., Smith, D.R., Yasarer, L.M. 2020. Comparative analysis of water budgets across the U.S. long-term agroecosystem research network. Journal of Hydrology. 588.
Christianson, L.E., Feyereisen, G.W., Hay, C.H., Tschirner, U.W., Keegan, K.J., Soupir, M.L., Hoover, N.L. 2020. Denitrifying bioreactor woodchip recharge: Media properties after nine years. Transactions of the ASABE. 63(2):407-416.
Deventer, J.M., Griffis, T.J., Roman, T.J., Kolka, R.B., Wood, J.D., Erickson, M.D., Baker, J.M., Millet, D.B. 2019. Error characterization of methane fluxes and budgets derived from a long-term comparison of open- and closed-path eddy covariance systems. Agricultural and Forest Meteorology. 278:107638.
Domingues, R.R., Sanchez-Monedero, M.A., Spokas, K.A., Melo, L.C., Trugilho, P.F., Valenciano, M.N., Silva, C.A. 2020. Enhancing cation exchange capacity of weathered soils using biochar: feedstock, pyrolysis conditions and addition rate. Agronomy. 10(6):824.
Ezzati, G., Fenton, O., Healy, M.G., Christianson, L.E., Feyereisen, G.W., Thornton, S., Chen, Q., Fan, B., Ding, J., Daly, K. 2020. Impact of P inputs on the source-sink P dynamics of sediment along an agricultural ditch network. Journal of Environmental Management. 257.
Ezzati, G., Healy, M.G., Christianson, L.E., Feyereisen, G.W., Thorton, S. F., Daly, K., Fenton, O. 2019. Developing and validating a decision support tool for media selection to mitigate drainage waters. Ecological Engineering. 2:100010.
Fairbrother, A., Muir, D., Solomon, K.R., Ankley, G.T., Rudd, M.A., Boxall, A.B., Apell, J.N., Armbrust, K.L., Blalock, B.J., Rice, P.J. et al. 2019. Toward sustainable environmental quality: priority research questions for North America. Environmental Toxicology and Chemistry. 38(8):1606-1624.
Ferraz-Almeida, R., Spokas, K.A., De Oliveira, R.C. 2020. Columns and detectors recommended in gas chromatography to measure greenhouse emission and O2 uptake in soil: A review. Communications in Soil Science and Plant Analysis. 51(5):582-594.
Gamiz, B., Velarde, P., Spokas, K.A., Cox, L. 2019. Dynamic effect of fresh and aged biochar on the behavior of the herbicide mesotrione in soils. Journal of Agricultural and Food Chemistry. 67(34):9450-9459.
Gamiz, B., Hall, K., Spokas, K.A., Cox, L. 2019. Understanding activation effects on low-temperature biochar for optimization of herbicide sorption. Agronomy. 9(10):588.
Ginakes, P., Grossman, J., Baker, J.M., Sooksa-nguan, T. 2019. Tillage intensity influences nitrogen cycling in organic kura clover living mulch. Nutrient Cycling in Agroecosystems. 116:71-82.
Fisher, J.B., Lee, B., Purdy, A.J., Halverson, G.H., Dohlen, M.B., Cawse- Nicholson, K., Wang, A., Anderson, R.G., Aragon, B., Arain, M., Baldocchi, D.D., Baker, J.M., Barral, H., Bernacchi, C.J., Bernhofer, C., Biraud, S.C. , Bohrer, G., Brunsell, N., Cappelaere, B., Castro-Contreras, S., Chun, J., Conrad, B.J., Cremonese, E., Demarty, J., Desai, A.R., Ligne, A.D., Foltýnová, L., Goulden, M.L., Griffis, T.J., Grunwald, T., Johnson, M.S., Kang, M., Kelbe, D., Kowalska, N., Lim, J., Mainassara, I., McCabe, M.F., Missik, J.E., Mohanty, B.P., Moore, C.E., Morillas, L., Morrison, R., Munger, J., Posse, G., Richardson, A.D., Russell, E.S., Ryu, Y., Sanchez- Azofeifa, A., Schmidt, M., Schwartz, E., Sharp, I., Šigut, L., Tang, Y., Hulley, G., Anderson, M.C., Hain, C., French, A.N., Wood, E., Hook, S. 2020. ECOSTRESS: NASA⿿s next generation mission to measure evapotranspiration from the International Space Station. Water Resources Research. 56(4).
Novak, J.M., Spokas, K.A., Johnson, M.G. 2018. Concentration and release of phosphorus and potassium from lignocellulosic and manure-based biochars from fertilizer reuse. Frontiers in Sustainable Food Systems.
Ranaivoson, A., Rice, P.J., Moncrief, J.F., Feyereisen, G.W., Dittrich, M. 2019. Acetochlor and atrazine dissipation in a woodchip denitrifying bioreactor: A comparison of experimental results with model estimates. International Journal of Hydrology. 3(4):286-306.
Souza, E.F., Soratto, R.P., Sandana, P., Venterea, R.T., Rosen, C. 2020. Split application of stabilized ammonium nitrate improved potato yield and nitrogen-use efficiency with reduced application rate in tropical sandy soils. Field Crops Research. 254.
Spiegal, S.A., Kleinman, P.J., Endale, D.M., Bryant, R.B., Dell, C.J., Goslee, S.C., Meinen, R.J., Flynn, K.C., Baker, J.M., Browning, D.M., McCarty, G.W., Bittman, S., Carter, J.D., Cavigelli, M.A., Duncan, E.W., Gowda, P.H., Li, X., Ponce, G., Raj, C., Silveira, M., Smith, D.R., Arthur, D.K., Yang, Q. 2020. Manuresheds: Advancing nutrient recycling in US agriculture. Agricultural Systems. 182:102813.
Toczydlowski, A., Slesak, R., Kolka, R., Venterea, R.T., D'Amato, A., Palik, B. 2019. Effect of simulated emerald ash borer infestation on nitrogen cycling in black ash (Fraxinus nigra) wetlands in northern Minnesota, USA. Forest Ecology and Management. 458:117769.
Venterea, R.T., Coulter, J., Clough, T. 2020. Nitrite accumulation and nitrogen gas production increase with decreasing temperature in urea- mended soils: Experiments and modeling. Soil Biology and Biochemistry. 142:107727.
Wilson, M., Baker, J.M., Allan, D.L., Pagliari, P.H. 2019. Comparing methods for overseeding winter rye into standing soybean. Agrosystems, Geosciences & Environment. 2(1):1-7.

Progress 10/01/18 to 09/30/19

Outputs
Progress Report Objectives (from AD-416): 1. Develop irrigation and drainage strategies in the North Central United States to protect water and soil resources a. Determine the potential of amendments to mitigate leaching and contamination of groundwater from agricultural operations. b. Identify materials and designs that will maximize contaminant removal from subsurface drainage water. 2. Identify and test innovative management practices to reduce potential adverse impacts on water quality or conserve water resources. a. Evaluate the effectiveness of low-input turf and management practices to reduce contaminant transport with runoff. b. Identify and test management practices to reduce reactive nitrogen leakage from dairy farming systems. c. Determine the impact of perenniallizing practices on the nutrient and water balances of corn/soybean systems. d. Determine the influence of management practices and water conservation strategies on water use and the occurrence and fate of contaminants in urban agriculture. 3. Conduct research as part of the LTAR network, and in concert with similar long-term, land-based research infrastructure in the U.S., use the Upper Mississippi River Basin LTAR site to improve the observational capabilities and data accessibility of the LTAR network and support research to sustain or enhance agricultural production and environmental quality in agroecosystems characteristic of the Upper Mississippi River Basin. Research and data collection are planned and implemented based on the LTAR site application and in accordance with the responsibilities outlined in the LTAR Shared Research Strategy, a living document that serves as a roadmap for LTAR implementation. Participation in the LTAR network and test innovative management practices to reduce potential adverse impacts on water quality or conserve water resources includes research and data management in support of the ARS GRACEnet and DAWG projects. Approach (from AD-416): Protecting the integrity and supply of our water resources is one of the most important issues we will face this century and therefore the foundation of our project⿿s objectives (objectives 1 and 2). Our research approach requires laboratory to field scale investigations focusing on two strategies, prevention and mitigation. With the prevention strategy we will identify and understand the fate of potential water contaminants (e.g. agrochemicals: fertilizer, pesticides; anthropogenic compounds) and develop practices to prevent or minimize the off-site transport of contaminants from their site of application or point of origin. For instance, we will evaluate the fate of biochar and its efficacy as a soil amendment to reduce the leaching of agrochemicals (subobjective 1a), management practices to minimize agrochemical transport with storm runoff from low-input turf (subobjective 2a.1), and the occurrence of contaminants in urban agricultural systems and the influence of water conservation and management practices on contaminant availability (subobjective 2d). In addition, we will determine the influence of perennial cover crops and the use of different irrigation and nitrogen rates to reduce transport of nutrients with runoff and drainage from row crops subobjective 2c). Model simulations will also be used to predict nitrate loads in tile drainage from a concentrated animal feeding operations (CAFO) dairy and simulate the efficacy of alternative practices to reduce loads (subobjective 2b). In circumstances where contaminants are transported off-site with overland flow or leaching, mitigation strategies will be taken to remove contaminants from runoff and tile drainage before they reach surface waters or groundwater. Mitigation approaches include plot-scale studies to identify optimal buffer size and management of low-input turf for the removal of contaminants transported with runoff (subobjective 2a.2), while field and modeling experiments will identify the most effective bioreactor design and materials for removing nutrients from subsurface drainage water (subobjective 1b). Laboratory, field, and small watershed studies will be employed to enhance and extend the research that has been initiated to develop aspirational farming practices (ASP) for the Upper Mississippi River Basin and to compare their environmental and economic metrics against business as usual (BAU) farming practices in the region. Management practices that will be explored include maintenance of continuous living cover in sensitive locations on the landscape, and downstream or down-gradient practices that remove excess nutrients and reduce N2O emissions. Our multidisciplinary team and the interrelationship of our project subobjectives within and across these strategies will make progress towards the national goal for improved water resource security. The initial samples from the biochar aging citizen science experiment have been received back in the laboratory. A project website has been created on SciStarter (https://scistarter.org/biochar-soil-aging) to improve recruitment of volunteers for the project. The soil and biochar have been analyzed by x-ray fluorescence to detect the presence of metal cations in the soil and the associated fractions on the biochar. These samples have also been processed and analyzed for compositional changes in carbon, hydrogen and nitrogen. They are being sent for more detailed analyses by scanning electron microscopy and further elemental surface analyses. Additionally, wireless balance systems have also been developed to monitor the gain or loss in mass of biochar samples while they undergo drying or moisture sorption (±10 mg). These systems can be enclosed in environments of known temperature, relative humidity and carbon dioxide concentrations, so the kinetics of the moisture sorption process can be determined on fresh and aged biochar samples. This work has demonstrated that the rate limiting step for moisture interaction with biochar is driven by the phase change (first order process) and not a diffusional limitation. Alterations in sorption characteristics for the aged biochar for a variety of chemical compounds is still ongoing. An experiment identifying materials and designs that will maximize contaminant removal from subsurface drainage water has been conducted, water analyses completed, and experimental data prepared for statistical analysis. Data on the percentage of system flow treated by the bioreactors have been prepared and are being analyzed. All water analyses have been completed on system and bioreactor outlet flow. A continuous nitrate-N concentration sensor and a turbidity sensor have been installed at the system inlet. Flow through the bioreactor beds was impeded last year, preventing planned tracer tests, which will be delayed a year until planned renovations are completed. Experiments are underway to provide a second field season of data evaluating the effectiveness of low-input turf and management practices to reduce contaminant transport with runoff. Field plots planted with a low-input fine fescue turfgrass are being managed as either a golf course fairway or residential lawn. Runoff collection gutters were repaired, repositioned and tested. Instrumentation for runoff collection was installed at each plot and calibrated. The manifold systems designed to deliver run-on for the filter strip experiments were repaired or modified to accommodate experimental needs. Water samples, collected during the first field season, were analyzed for nutrients and a tracer compound to characterize off-site chemical transport with runoff. Extraction and analysis of pesticides in the runoff water has been initiated. Research identifying and testing management practices to reduce reactive nitrogen leakage from dairy farming systems in ongoing. A peer-reviewed journal article on manure application methods has been published. The drainage component of the Integrated Farm Systems Model (IFSM) has been tested against field measurements reported in a number of published studies and a manuscript has been started. Collaboration on dairy- related environmental studies with other ARS units in the Dairy Agroecosystem Working Group has continued. Eddy covariance systems were installed in our new LTAR fields, one in the conventional corn/soy field and the other in our perennial living mulch field. Kura clover was planted in the perennial field to establish the living mulch system. The eddy covariance data will allow the direct measurement of evapotranspiration in both systems, which is necessary to compute the water balances for each system. A literature search and investigation of recorded historical land use to determine potential contaminants of concern for urban agriculture is ongoing. Established community gardens are being visited to observe currently utilized management practices and identify urban agricultural inputs. Collection of soil samples from vacant lots continues, and efforts to identify and sample additional locations where urban food production is anticipated is underway. Investigation, testing and refinement of extraction and analysis methodologies are ongoing. These efforts will identify the occurrence of contaminants in urban agriculture, begin to evaluate potential sources of contaminants and lead to the development and testing of management practices to mitigate concerns and provide customer/stakeholders with guidelines for healthy food production in areas with anthropogenic contaminants. Two new experiments were initiated. The first is a cooperative effort with several other LTAR locations, led by the Lower Chesapeake Bay LTAR, to determine the lag time of watersheds with a novel technique. The second will develop new methods to map nitrate concentrations in watersheds and related spatial differences to edge-of-field conservation practices. Accomplishments 01 Detection of changes in lake evaporation. Biochar aging in soil is multifaceted. There is need to understand how biochar changes after it has been placed into various soils. ARS scientists in St. Paul, Minnesota, investigated changes in the sorption behavior of a herbicide to fresh and aged biochars. The same biochar was aged for 6 months buried in mesh bags at 3 locations across the U.S. (Idaho, Wisconsin and South Carolina). The biochar that was aged in the Wisconsin soil resulted in the largest increase in sorption behavior. Whereas the biochar that were aged in South Carolina and Idaho soils were not significantly altered in their sorption behavior. The exact reason for these differences could not be conclusively demonstrated, but it is believed linked to the alterations in the dissolved organic compounds sorbed to the biochar and/or alterations to the salt content following soil incorporation. These results clearly show there is a need to better understand the mechanisms of chemical alterations to biochar resulting from soil exposure to properly assess longer term impacts of biochar additions. These results are significant to farmers and policy makers and will assist scientists and engineers in understanding the potential pathways for improved mechanisms of biochar⿿s chemical sorption behavior. 02 Biochar aging in soil is multifaceted. There is a need to understand how biochar changes after it has been placed into various soils. ARS scientists, St. Paul, Minnesota, investigated changes in the sorption behavior of a herbicide to fresh and aged biochars. The same biochar was aged for 6 months buried in mesh bags at 3 locations across the United States (Idaho, Wisconsin, and South Carolina). The biochar that was aged in the Wisconsin soil resulted in the largest increase in sorption behavior. Whereas the biochar that were aged in South Carolina and Idaho soils were not significantly altered in their sorption behavior. The exact reason for these differences could not be conclusively demonstrated, but it is believed linked to the alterations in the dissolved organic compounds sorbed to the biochar and/or alterations to the salt content following soil incorporation. These results highlight the need to understand the mechanisms of chemical alterations to biochar resulting from soil exposure to properly assess longer term impacts of biochar additions. These results are significant to farmers and policy makers and will assist scientists and engineers in understanding the potential pathways for improved mechanisms of biochar⿿s chemical sorption behavior.

Impacts
(N/A)

Publications

Ghane, E., Feyereisen, G.W., Rosen, C.J. 2019. Efficacy of bromide tracers for evaluating the hydraulic performance of denitrification beds. Journal of Hydrology. 574:129-137.
Dobbratz, M., Baker, J.M., Grossman, J., Wells, M., Ginakes, P. 2019. Rotary zone tillage improves corn establishment in a kura clover living mulch. Soil & Tillage Research. 189(6):229-235.
Holly, M.A., Kleinman, P.J., Bryant, R.B., Bjorneberg, D.L., Rotz, C.A., Baker, J.M., Boggess, M.V., Brauer, D.K., Chintala, R., Feyereisen, G.W., Gamble, J.D., Leytem, A.B., Reed, K., Vadas, P.A., Waldrip, H. 2018. Identifying challenges and opportunities for improved nutrient management through U.S.D.A's Dairy Agroecosystem Working Group. Journal of Dairy Science. 101(7):6632-6641.
Kleinman, P.J., Spiegal, S.A., Rigby Jr., J.R., Goslee, S.C., Baker, J.M., Bestelmeyer, B.T., Boughton, R., Bryant, R.B., Cavigelli, M.A., Derner, J. D., Duncan, E.W., Goodrich, D.C., Huggins, D.R., King, K.W., Liebig, M.A., Locke, M.A., Mirsky, S.B., Moglen, G.E., Moorman, T.B., Pierson Jr., F.B., Robertson, G., Sadler, E.J., Shortle, J., Steiner, J.L., Strickland, T.C., Swain, H., Williams, M.R., Walthall, C.L., Tsegaye, T.D. 2018. Advancing the sustainability of US agriculture through long-term research. Journal of Environmental Quality. 47(6):1412-1425.
Alexander, J.R., Venterea, R.T., Baker, J.M., Coulter, J.A. 2019. Kura clover living mulch: Spring management effects on nitrogen. Agronomy. 9(2), 69:1-14.
Jang, J., Anderson, E., Venterea, R.T., Sadowsky, M., Rosen, C., Feyereisen, G.W., Ishii, S. 2019. Cold-adapted denitrifying bacteria in woodchip bioreactor. Frontiers in Microbiology. 10(635):1-12.
Souza, E., Rosen, C., Venterea, R.T. 2019. Contrasting effects of inhibitors and biostimulants on agronomic performance and reactive nitrogen losses during irrigated potato production. Field Crops Research. 241:1-11.
Fidel, R.B., Laird, D.A., Spokas, K.A. 2018. Sorption of ammonium and nitrate to biochars is electrostatic and pH-dependent. Nature Scientific Reports. 8(1):1-10.
Novak, J.M., Moore, E., Spokas, K.A., Hall, K., Williams, A. 2018. Future biochar research directions. In: Ok, Y.S., Tsang, D.C., Bolan, N., Novak, J.M., editors. Biochar from Biomass and Waste. 1st edition, New York, NY: Academic Press. p. 423-432.
Fuertes-Mendizabal, T., Huerfano, X., Vega-Mas, I., Torralbo, F., Menendez, S., Ippolito, J.A., Kammann, C., Wrage-Monnig, N., Cayuela, M., Borchard, N., Spokas, K.A., Novak, J.M., Gonzalez-Moro, M., Gonzalez-Murua, C., Estavillo, J. 2019. Biochar reduces the efficiency of nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) mitigating N2O emissions. Nature Scientific Reports. 9(2346):1-16.
Gamiz, B., Velarde, P., Spokas, K.A., Celis, R., Cox, L. 2019. Changes in sorption and bioavailability of herbicides in soil amended with fresh and aged biochar. Geoderma. 337:341-349.
Borchard, N., Schirrmann, M., Cayuela, M.L., Kammann, C., Wrange-Monnig, N. , Estavillo, J., Fuertes-Mendizabal, T., Sigua, G.C., Spokas, K.A., Ippolito, J., Novak, J.M. 2018. Biochar, soil and land-use interactions that reduce nitrate leaching and N2O emissions: A meta-analysis. Science of the Total Environment. 651:2354-2364.
Ghane, E., Feyereisen, G.W., Rosen, C.J. 2019. Data of bromide sorption experiments with woodchips and tracer testing of denitrification beds treating agricultural drainage water. Data in Brief. 574:129-137.
Sigua, G.C., Novak, J.M., Watts, D.W., Ippolito, J.A., Ducey, T.F., Johnson, M.G., Spokas, K.A. 2019. Phytostabilization of Zn and Cd in mine soil using corn in combination with manure-based biochar and compost. Environments. 6(6):69.
Weyers, S.L., Thom, M.D., Forcella, F., Eberle, C.A., Matthees, H.L., Gesch, R.W., Ott, M., Feyereisen, G.W., Strock, J.S., Wyse, D. 2019. Potential for nutrient loss reduction in cover cropped systems in the Upper Midwest. Journal of Environmental Quality. 48(3):660-669.

Progress 10/01/17 to 09/30/18

Outputs
Progress Report Objectives (from AD-416): 1. Develop irrigation and drainage strategies in the North Central United States to protect water and soil resources a. Determine the potential of amendments to mitigate leaching and contamination of groundwater from agricultural operations. b. Identify materials and designs that will maximize contaminant removal from subsurface drainage water. 2. Identify and test innovative management practices to reduce potential adverse impacts on water quality or conserve water resources. a. Evaluate the effectiveness of low-input turf and management practices to reduce contaminant transport with runoff. b. Identify and test management practices to reduce reactive nitrogen leakage from dairy farming systems. c. Determine the impact of perenniallizing practices on the nutrient and water balances of corn/soybean systems. d. Determine the influence of management practices and water conservation strategies on water use and the occurrence and fate of contaminants in urban agriculture. Approach (from AD-416): Protecting the integrity and supply of our water resources is one of the most important issues we will face this century and therefore the foundation of our project�s objectives (objectives 1 and 2). Our research approach requires laboratory to field scale investigations focusing on two strategies, prevention and mitigation. With the prevention strategy we will identify and understand the fate of potential water contaminants (e.g. agrochemicals: fertilizer, pesticides; anthropogenic compounds) and develop practices to prevent or minimize the off-site transport of contaminants from their site of application or point of origin. For instance, we will evaluate the fate of biochar and its efficacy as a soil amendment to reduce the leaching of agrochemicals (subobjective 1a), management practices to minimize agrochemical transport with storm runoff from low-input turf (subobjective 2a.1), and the occurrence of contaminants in urban agricultural systems and the influence of water conservation and management practices on contaminant availability (subobjective 2d). In addition, we will determine the influence of perennial cover crops and the use of different irrigation and nitrogen rates to reduce transport of nutrients with runoff and drainage from row crops (subobjective 2c). Model simulations will also be used to predict nitrate loads in tile drainage from a concentrated animal feeding operations (CAFO) dairy and simulate the efficacy of alternative practices to reduce loads (subobjective 2b). In circumstances where contaminants are transported off-site with overland flow or leaching, mitigation strategies will be taken to remove contaminants from runoff and tile drainage before they reach surface waters or groundwater. Mitigation approaches include plot-scale studies to identify optimal buffer size and management of low-input turf for the removal of contaminants transported with runoff (subobjective 2a.2), while field and modeling experiments will identify the most effective bioreactor design and materials for removing nutrients from subsurface drainage water (subobjective 1b). Our multidisciplinary team and the interrelationship of our project subobjectives within and across these strategies will make progress towards the national goal for improved water resource security. Objective 1a. Website at SciStarter (https://scistarter.com/project/ 20309-Biochar-Soil-Aging) has been established to solicit volunteers for the citizen science aging project. Experiments have been initiated for the colloidal transport of sorbed contaminants to assess net impacts on soil transport. Experiments into the interaction of water and CO2 with biochar have been initiated and the first series of biochars have been evaluated. Objective 1b. The test apparatus for the bioreactor laboratory experiment was designed and built. An experiment testing the addition of a readily available C source (acetate) to denitrifying bioreactor columns was conducted. Treatments included flow direction (up vs. down) and location of C source addition (inlet vs. midport). Water analyses were completed. The experimental data need to be analyzed. Installation of sensors and related equipment were completed at the field woodchip bioreactor site. Drainage flow to the system stopped from the end of July 2017 until snow melt runoff in March 2018. Since flow was re- established in the spring of 2018, flow through the bioreactor system has been impeded by sediment loads that occur after large precipitation events and subsequent high flows. ARS scientists in St. Paul, Minnesota are working with cooperators � Soil Water Conservation District, Minnesota Department of Agriculture, and engineering firm personnel � on solutions to the sediment issues, which have negatively impacted the capacity of the bioreactor cells to remove nitrate-N from subsurface drainage water. Objective 2a. Field plots were reconstructed and planted with low-input turfgrass, a fine fescue mixture. The rainfall simulator was modified and uniformity tests were completed. Runoff collection gutters were repositioned and tested. Instrumentation for runoff collection was repaired and installed in the plots. Manifold systems designed to deliver runon for the filter strip experiments were enlarged to accommodate a new experimental design. Methodology for the extraction and analysis of the compounds of interest were investigated and procedural modifications and validations were initiated. Rainfall simulation and runon/runoff experiments are underway. Objective 2b. Subsurface drainage flow, nitrate concentration, and nitrate load data were vetted and analyzed for a rich, nine-year hydrologic dataset from an on-farm collaboration. Six years of the data were used to investigate the potential to reduce nitrate-N subsurface drainage losses by shifting the timing and delivery of dairy manure to silage corn crops. Subsurface drainage losses were reduced by applying a lesser rate of manure during the growing season when crop uptake was high. The lower application rate and nitrate-N losses were associated with a reduction in soil nitrate concentration. Manurial N-use efficiency was also improved. Additional investigations of soil and water impacts of nutrient management in dairy systems are ongoing, including simulation modeling and influences of cold season processes on water quality. Objective 2c. Established new fields for our LTAR project, one which will be our �business as usual� treatment of conventional corn/soy rotation, and the other will be our �aspirational� treatment. Installed eddy covariance towers in each field, buried sample lines to convey gas back to a trailer where they feed a nitrous oxide analyzer, and installed soil moisture sensors and temperature sensors. Soil samples were also taken and analyzed to provide baseline soil carbon data. Objective 2d. A literature search and investigation of recorded historical land use is underway to determine potential contaminants of concern for urban agriculture. Established community gardens have been visited for observation of currently utilized management practices and identification of urban agricultural inputs. Collection of soil samples has been initiated from vacant lots and locations throughout the metropolitan area where urban food production is in progress or anticipated. A location for scientifically controlled replicated plots has been identified. Investigation and testing of extraction and analysis methodologies has been initiated and is ongoing. Accomplishments 01 Dairy manure management practices reduce tile drainage nitrate-nitrogen losses. The U.S. dairy industry is dramatically consolidating animals onto fewer, larger farms, increasing concern for negative soil, water quality, and atmospheric impacts. ARS researchers at Saint Paul, Minnesota, investigated environmental impacts of a manured silage corn- alfalfa cropping system on tile-drained fields on a large confinement dairy, amassing an extensive nine-year dataset of soil, water, and atmospheric measurements. By reducing manure application rates and applying manure via center pivot irrigation during the growing season, tile drainage nitrate-nitrogen losses were reduced without affecting silage corn yields. This work demonstrated that manure rate reductions and growing season application can be successful; however, additional research on these data is revealing that there may be negative consequences to carbon balance in the soils over the long term. Thus, the comprehensive approach to all relevant environmental balances is necessary to inform any system or management changes. The practice of applying manure through center pivot irrigation has not been widely adopted, primarily because of additional mechanical complexities compared to standard practice of injecting manure in the fall. 02 Chemical application setbacks safeguard water quality. Management of turfgrass on golf courses and athletic fields often involves application of plant protection products to maintain turfgrass health and performance. However, the carrying of fertilizer and pesticides with rainfall runoff from the area they were applied to neighboring surface waters can enhance algal blooms, promote eutrophication and may be harmful to sensitive aquatic organisms and ecosystems. ARS researchers at Saint Paul, Minnesota, evaluated the effectiveness of chemical application setbacks to reduce the off-site movement of chemicals with storm runoff. Experiments with water soluble tracer compounds confirmed that an increase in application setback distance by 6m resulted in a 43% reduction in the total percentage of applied chemical transported with the storm runoff to neighboring areas. Application setbacks offer turfgrass managers a mitigation approach that requires no additional resources or time inputs and may serve as an alternative practice when buffers are less appropriate for land management objectives or site conditions. This information is useful to grounds superintendents for designing chemical application strategies to maximize environmental stewardship, and to scientists and regulators working with chemical transport and risk models. 03 Biochar aging changes pesticide sorption influencing pest control and environmental fate. Impairment of water resources from applied agrochemicals typically involves transport through the soil system where colloidal particles may play an important role. Biochar, a carbon-rich soil amendment, can change with environmental aging (freeze- thaw and wet-dry cycles), which may alter its carbon sequestration potential and have water quality and ecosystem impacts. ARS researchers at Saint Paul, Minnesota, examined the impact of soil aging of an oak hardwood biochar that was buried in a silt loam soil for 6 months in the Upper Midwest (Wisconsin). There was a significant difference observed in the amount of pesticide sorption as a function of aging, with the soil aged biochar sample sorbing higher amounts (>85%) of all pesticides in the laboratory experiments compared to the fresh biochar samples which sorbed less than 15%. Both biochar samples had similar chemistries with no oxidation or chemical alterations observed after 6-months. These results are significant to farmers and policy makers and will assist scientists and engineers in understanding the potential alteration in the sorption potential for biochar once it is applied to soils. These results show the variability of biochar sorption capacities and changes with time after its addition to soil, which will affect the long-term control of pests and environmental fate of applied pesticides. 04 Nitrate recycling. Nitrate contamination of surface and ground waters is a serious problem in many agricultural regions. It is a human health risk, and also contributes to eutrophication of fresh water and the Gulf of Mexico. Most mitigation efforts focus on denitrification � encouraging microbes to convert nitrate to nitrogen gas. This is inherently wasteful, since much energy is required to initially manufacture nitrogen fertilizer, so it is desirable to develop methods to recycle nitrate. ARS scientists in St. Paul, Minnesota developed a system that can separate nitrate from contaminated water and concentrate it for re-use as fertilizer. It is DC powered and runs on solar panels, so it is suitable for remote locations. A feasibility test was successfully conducted on a contaminated trout stream that has a nitrate concentration in excess of 20 ppm. The system was able to remove an average of 42% of the nitrate from water passing through it, concentrating it in a tank that ultimately reached a concentration exceeding 500 ppm, which was subsequently used elsewhere as fertilizer. This approach could be used to recover nitrate not only from streams, but also from contaminated wells, ponds, and lakes.

Impacts
(N/A)

Publications

Ochsner, T., Schumacher, T.W., Venterea, R.T., Feyereisen, G.W., Baker, J. M. 2018. Soil water dynamics and nitrate leaching under corn-soybean rotation, continuous corn, and kura clover. Vadose Zone Journal. 17:170028.
Joseph, S., Kammann, C.I., Shepard, J.G., Conte, P., Schmidt, H., Hagemann, N., Rich, A.M., Spokas, K.A., Marjo, C.E., Allan, J., Munroe, P., Mitchell, D.R., Donne, S., Graber, E.R. 2018. Microstructural and associated chemical changes during the composting of a high temperature biochar: Mechanisms for nitrate, phosphate and other nutrient retention and release. Science of the Total Environment. 618:1210-1223.
Baker, J.M., Griffis, T.J. 2017. Feasibility of recycling excess agricultural nitrate with electrodialysis. Journal of Environmental Quality. 46(6):1528-1534.
Vozhdayev, G.V., Spokas, K.A., Molde, J.S., Heilmann, S.M., Wood, B.M., Valentas, K.J. 2018. Impact of two hydrothermal carbonization filtrates on soil greenhouse production. Agronomy Journal. 2(1):48-61.
Lim, T., Spokas, K.A., Feyereisen, G.W., Weis, R.D., Koskinen, W. 2017. Influence of biochar particle size and shape on soil hydraulic properties. Journal of Environmental Science and Engineering. 5(1):8-15.
Almeida, R.F., De Bortoli Teixeira, D., Montanari, R., Bolonhezi, A.C., Teixeira, E.B., Moitinho, M.R., Panosso, A.R., Spokas, K.A., La Scala Junior, N. 2018. Ratio of CO2 and O2 as index for categorizing soil biological activity in sugarcane areas under contrasting straw management regimes. Soil Research. 56(4):373�381.
Xiao, K., Griffis, T.J., Baker, J.M., Bolstad, P.V., Erickson, M.D., Lee, X., Wood, J.D., Hu, C., Nieber, J.L. 2018. Evaporation from a temperate closed-basin lake and its impact on present, past, and future water level. Journal of Hydrology. 561:59-75.
Christianson, L.E., Feyereisen, G.W., Lepine, C., Summerfelt, S.T. 2018. Plastic carrier polishing chamber reduces pollution swapping from denitrifying woodchip bioreactors. Aquacultural Engineering. 81:33-37. https;//doi.org/10.1016/j.aquaeng.2018.01.001.
Holly, M.A., Kleinman, P.J., Bryant, R.B., Bjorneberg, D.L., Church, C., Baker, M.E., Boggess, M.V., Chintala, R., Feyereisen, G.W., Gamble, J.D., Leytem, A.B., Reed, K., Rotz, C.A., Vadas, P.A., Waldrip, H., Brauer, D.K. 2018. Identifying challenges and opportunities for improved nutrient management through U.S.D.A's Dairy Agroecosystem Working Group. Journal of Dairy Science. 101:1-10.
Malone, R.W., Obrycki, J., Karlen, D.L., Ma, L., Kaspar, T.C., Jaynes, D.B. , Parkin, T.B., Lence, S., Feyereisen, G.W., Fang, Q., Richards, T.L., Gillette, K.L. 2018. Harvesting fertilized rye cover crop: simulated revenue, net energy, and drainage Nitrogen loss. Agricultural and Environmental Letters. 3:170041.
Novak, J.M., Ippolito, J.A., Ducey, T.F., Watts, D.W., Spokas, K.A., Trippe, K.M., Sigua, G.C., Johnson, M.G. 2018. Remediation of an acidic mine spoil: Miscanthus biochar and lime amendment affects metal availability, plant growth and soil enzymatic activity. Chemosphere. 205:709-718.
Mendes, K.F., Hall, K.E., Spokas, K.A., Koskinen, W.C., Tornisielo, V.L. 2017. Evaluating agricultural management effects on alachlor availability: Tillage, green manure, and biochar. Agronomy. 7(4):64.
Rice, P.J., Horgan, B.P., Hamlin, J.L. 2018. Off-site transport of fungicides with runoff: A comparison of flutolanil and pentachloronitrobeneze applied to creeping bentgrass managed as a golf course fairway. Ecotoxicology and Environmental Safety. 157:143-149.
Rice, P.J., Horgan, B.J., Barber, B.L., Koskinen, W.C. 2018. Chemical application strategies to protect water quality. Ecotoxicology and Environmental Safety. 156:420-427.
Gillette, K.L., Malone, R.W., Kaspar, T.C., Ma, L., Parkin, T.B., Jaynes, D.B., Fang, Q.X., Hatfield, J.L., Feyereisen, G.W., Kersebaum, K.C. 2018. N loss to drain flow and N2O emissions from a corn-soybean rotation with winter rye. Science of the Total Environment. 618:982-997.
Hagerman, N., Spokas, K.A., Schmidt, H., Kagi, R., Bohler, M., Bucheli, T. D. 2018. Activated carbon, biochar and charcoal: Linkages and synergies across pyrogenic carbon's ABC. Water. 10(2):182.
Gamble, J.D., Feyereisen, G.W., Papiernik, S.K., Wente, C.D., Baker, J.M. 2018. Summer fertigation of dairy slurry reduces soil nitrate concentrations and subsurface drainage nitrate losses compared to fall injection. Frontiers in Sustainable Food Systems. doi:
Tavares, R., Spokas, K.A., Hall, K., Colosky, E., De Souza, Z., La Scala, N. 2018. Sugarcane residue management impact soil greenhouse gas. Ci�ncia e Agrotecnologia. 42(2):195-203.
Roser, M., Feyereisen, G.W., Spokas, K.A., Mulla, D.J., Strock, J.S., Gutknecht, J. 2018. Carbon dosing increases nitrate removal rates in denitrifying bioreactors at low-temperature high-flow conditions. Journal of Environmental Quality. 47(4):856-864. doi: 10.2134/jeq2018.02.0082.
Ghane, E., Feyereisen, G.W., Rosen, C.J., Tschirner, U.W. 2018. Carbon quality of four-year-old woodchips in a denitrification bed treating agricultural drainage water. Transactions of the ASABE. 61(3):995-1000. doi: 10.13031/trans.12642.

Progress 10/01/16 to 09/30/17

Outputs
Progress Report Objectives (from AD-416): 1. Develop irrigation and drainage strategies in the North Central United States to protect water and soil resources a. Determine the potential of amendments to mitigate leaching and contamination of groundwater from agricultural operations. b. Identify materials and designs that will maximize contaminant removal from subsurface drainage water. 2. Identify and test innovative management practices to reduce potential adverse impacts on water quality or conserve water resources. a. Evaluate the effectiveness of low-input turf and management practices to reduce contaminant transport with runoff. b. Identify and test management practices to reduce reactive nitrogen leakage from dairy farming systems. c. Determine the impact of perenniallizing practices on the nutrient and water balances of corn/soybean systems. d. Determine the influence of management practices and water conservation strategies on water use and the occurrence and fate of contaminants in urban agriculture. Approach (from AD-416): Protecting the integrity and supply of our water resources is one of the most important issues we will face this century and therefore the foundation of our project�s objectives (objectives 1 and 2). Our research approach requires laboratory to field scale investigations focusing on two strategies, prevention and mitigation. With the prevention strategy we will identify and understand the fate of potential water contaminants (e.g. agrochemicals: fertilizer, pesticides; anthropogenic compounds) and develop practices to prevent or minimize the off-site transport of contaminants from their site of application or point of origin. For instance, we will evaluate the fate of biochar and its efficacy as a soil amendment to reduce the leaching of agrochemicals (subobjective 1a), management practices to minimize agrochemical transport with storm runoff from low-input turf (subobjective 2a.1), and the occurrence of contaminants in urban agricultural systems and the influence of water conservation and management practices on contaminant availability (subobjective 2d). In addition, we will determine the influence of perennial cover crops and the use of different irrigation and nitrogen rates to reduce transport of nutrients with runoff and drainage from row crops (subobjective 2c). Model simulations will also be used to predict nitrate loads in tile drainage from a concentrated animal feeding operations (CAFO) dairy and simulate the efficacy of alternative practices to reduce loads (subobjective 2b). In circumstances where contaminants are transported off-site with overland flow or leaching, mitigation strategies will be taken to remove contaminants from runoff and tile drainage before they reach surface waters or groundwater. Mitigation approaches include plot-scale studies to identify optimal buffer size and management of low-input turf for the removal of contaminants transported with runoff (subobjective 2a.2), while field and modeling experiments will identify the most effective bioreactor design and materials for removing nutrients from subsurface drainage water (subobjective 1b). Our multidisciplinary team and the interrelationship of our project subobjectives within and across these strategies will make progress towards the national goal for improved water resource security. Objective 1a: Volunteers have been initially solicited and initial citizen science trials have been started. Additional volunteers will continue to be solicited into next fiscal year. Project website will be established by the end of the year (hypothesis 1a.1). Laboratory equipment and method development has been acquired for biochar aging and pesticide transport experiments (hypotheses 1a.2 and 1a.3). A new collaboration has been established with the Spanish Research Council Institute of Natural Resources and Agrobiology in Seville, Spain. Additionally, a graduate student from Brazil visited the St. Paul, Minnesota laboratory to collaborate on soil type � climate impacts on biochar pesticide sorption. Objective 1b: The first of three flow regimes of the denitrifying bioreactor laboratory experiment to maximize nitrate-N removal (goal 1b.1) is set to begin in mid-July 2017 and be completed by September 1, 2017. The set-up is operational and currently in pre-test mode. Flow and water quality data are being collected from the three-bed field bioreactor in Faribault County, Minnesota (hypothesis 1b.2). Presentation to the local Drainage Authority of flow and nitrate-N load data from the first year of operation is planned for August 1, 2017. Objective 2a: Establishment of low-input turfgrass plots began with laser leveling the research area to a consistent slope of 5�1% from east to west. This entire area was seeded with a mixture of 40% �Beacon� hard fescue, 20% �Radar� Chewings fescue, 20% �Shoreline� slender creeping red fescue, and 20% �Quatro� sheep fescue. Starter fertilizer was applied and the area was periodically irrigated to maintain surface moisture throughout germination and establishment. Runoff gutters, flumes, flow meters and automated samplers were installed (hypothesis 2a.1). A literature search is underway to identify contaminants of concern (hypothesis 2a.2) and extraction and analysis methodologies (hypothesis 2a.1 and 2a.2) to be utilized in the low-input turfgrass runoff studies and the low-input turfgrass filter strip/buffer research. Objective 2b: We took part in discussions with other ARS locations in DAWG to develop coordinated research to reduce N losses from dairy systems. Calculation of subsurface drainage nitrate-N and dissolved phosphorus loads will be completed along with analysis of soil N and P at four depths over 10 sample years. A manuscript to compare nitrate-N drainage concentrations and losses on fields with fall manure injection versus in-season fertigation (hypothesis 2b.1) has been started. Validation testing is well underway for the Integrated Farming System Model, which is being used to test strategies to reduce reactive N leakage from dairy systems by 20% (hypothesis 2b.2). A critical test of the model�s predictions of drainage nitrate-N losses under manured systems (tile drained and non-tiled) is being conducted on nine sites encompassing 48 site-years. Objective 2c: Established new field experiment to address the hypothesis that perennializing practices will reduce reactive N loss from corn/ soybean systems (hypothesis 2c.1) Objective 2d: A literature search has been initiated to identify potential contaminants of concern in urban environments and method development is in progress for the extraction and analysis of contaminants (hypotheses 2d.1, 2d.2). Several innovative urban agricultural systems have been identified and are under consideration for research pertaining to hypothesis 2d.3. Communication with potential collaborators and identification of research locations has been initiated (hypothesis 2d.1, 2d.2, 2d.3).

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