PERENNIALIZING FARMED POTHOLES TO IMPROVE ECOSYSTEM SERVICES

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: AFRI COMPETITIVE GRANT
• Reporting Frequency: Annual
• Accession No.: 1015251
• Grant No.: 2018-67019-27886
• Cumulative Award Amt.: $475,000.00
• Proposal No.: 2017-05497
• Project Start Date: Apr 1, 2018
• Project End Date: Mar 31, 2023
• Grant Year: 2018
• Program Code: [A1401]- Foundational Program: Soil Health

Recipient Organization
IOWA STATE UNIVERSITY
2229 Lincoln Way
AMES,IA 50011

Performing Department
Agronomy

Non Technical Summary
Our project will determine the extent to which the perennial bioenergy crop miscanthus (Miscanthus × giganteus Greef et Deu.) improves nutrient cycling and ecosystem services compared to annual crops grown in farmed potholes. Potholes are agroecological 'hot spots' characterized by low-lying, poorly drained, sub-field regions that are disproportionately vulnerable to poor crop production and impaired ecosystem services (Zedler, 2003). Annual crops typically planted in potholes are highly susceptible to excess moisture stress, which leads to poor yields, financial loss, and adverse environmental impacts (Bonner et al., 2016; Brandes et al., 2016). As climate patterns become increasingly variable, farmed potholes will become even more exposed to risk (Moore et al., 2014).Farmers require management options in addition to annual row crops to reduce vulnerability and improve the ecosystem service performance associated with sensitive portions of their fields (Moore et al., 2014; Bonner et al., 2016). Numerous studies have shown that targeted integration of perennials into a working landscape can disproportionally enhance ecosystem services (e.g., Zedler, 2003; Boody et al., 2005; Walter et al., 2007 Asbjornsen et al., 2014; Schulte et al., in revision), but none have explicitly addressed pothole wetlands. Wetlands are generally recognized as important locations for hydrologic cycling and the provision of multiple ecosystem services, including flood mitigation, groundwater recharge, water purification, carbon sequestration, and wildlife habitat (e.g., Batzer et al., 1999; Detenbeck et al., 2002; Gleason et al., 2004; Zedler and Kercher, 2005). While the benefits of connected wetland systems are acknowledged, comparatively less is known about potholes, which are enclosed depressions found over a wide range of geologic areas and climates, particularly those in heterogenous landscapes of the US Midwest Corn Belt. We propose perennial bioenergy grasses as an innovative "high risk/high reward" land management option that could potentially reduce vulnerability and improve ecosystem services in corn/soybean systems by strategically placing more flood tolerant perennial bioenergy grass in farmed potholes. We chose miscanthus as the focal perennial bioenergy crop option for this proposal because of prior research that supports improved ecosystem service performance (Table 1), extreme moisture stress tolerance (Mann et al., 2013), and major role as a candidate bioenergy crop in the US (Langholtz et al., 2016; VanLoocke et al., 2017).Using a spatially explicit integrated measurement and modeling approach, we propose to test the hypothesis that incorporating the perennial bioenergy crop miscanthus into the rain-fed Midwest US could "significantly increase the output of three ecosystem services compared with the current management system for the region" (AFRI RFA, p. 34), specifically by increasing biomass production, decreasing nitrate leaching, and improving the greenhouse gas (GHG) balance relative to the current corn/soy cropping systems in the region (Table 1). We propose to test this hypothesis by establishing a new manipulative and replicated field experiment; extending existing field trial data; and integrating associated data within an established, process-based agroecosystem model (Integrated Biosphere Simulator - agricultural version (AgroIBIS; Kucharik et al., 2003; Zipper et al., 2015). We also propose to extend our research to the public by integrating our new findings into an existing educational and outreach learning platform: People in Ecosystems/Watershed Integration (PEWI; Chennault et al., 2016).

Animal Health Component

75%

Research Effort Categories

Basic

25%

Applied

75%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
131	0199	1070	25%
102	0199	1070	25%
112	0399	1070	25%
132	0499	2050	25%

Knowledge Area
102 - Soil, Plant, Water, Nutrient Relationships; 112 - Watershed Protection and Management; 132 - Weather and Climate; 131 - Alternative Uses of Land;

Subject Of Investigation
0199 - Soil and land, general; 0399 - Watersheds and river basins, general; 0499 - Atmosphere, general/other;

Field Of Science
2050 - Hydrology; 1070 - Ecology;

Keywords

farmed potholes

miscanthus

nitrate

nitrous oxide

perennial crops

Goals / Objectives
The long-term goals we are pursuing are to more fully understand the implications of subfield integration of perennial bioenergy crops as an innovative management strategy to improve agroecosystem performance and adaptation in the US Corn Belt; to communicate our results with diverse audiences; and to assist others with the strategic implementation of perennials within annual crop fields. Ultimately, we expect this project to transform strategic integration of perennials from a high risk/high reward research endeavor to a low risk/high reward practice feasible on a broad scale. We propose to work toward our long-term goals by pursuing three interlinked fundamental objectives:Objective 1: Quantify biomass production, profitability, soil nitrous oxide (N2O) and carbon dioxide (CO2) emissions, and NO3- leaching under conventional corn/soybean systems versus miscanthus in farmed potholes;Objective 2: Assess changes in ecosystem services provided by growing miscanthus in farmed potholes in the Midwest US; and,Objective 3: Facilitate support for the strategic adoption of low risk/high reward perennial systems by farmers, farmland owners, and their advisors for the joint production of food, bioenergy, and ecosystem services from prairie pothole landscapes.

Project Methods
C1.2 Objective 1 methods - Production and Profit will be measured using protocols established previously by our group (Wilson et al., 2014; Boersma & Heaton, 2014; Brandes et al., 2016). Briefly, aboveground biomass production will be estimated by harvesting one square meter from each of five sub-replicate areas in each of the three replicate plots annually following senescence and when the pothole has drained. Plants will be cut 10 cm from the soil surface, weighed fresh, then a subsample of representative phytomers taken and weighed. We will calculate profitability in an established framework using yield monitor data intersected with soil maps and crop budgets following Brandes et al. (2016).Soil GHG fluxes will be measured using automated flux chamber systems. Soil-atmosphere GHG fluxes will be measured at high frequency across pothole transects on lowland to upland gradients. Co-PI Hall's group has built 24 dynamic (open-system) chambers based on a modification of the (Rayment & Jarvis, 1997) design as implemented by Bowling et al. (2015). This chamber design largely eliminates the concerns with inadequate venting, artificial pressure perturbations, the Venturi effect, and static chamber flux modeling that have been noted elsewhere (Fang & Moncrieff, 1998; Livingston et al., 2005; Venterea, 2013; Xu et al., 2006). Chamber inlets and outlets are sampled at constant flow rates during a given measurement period via pumps and mass flow controllers controlled by a datalogger. Inlets and outlets from multiple chambers are multiplexed using a custom manifold. Mole fractions of N2O are measured using a Teledyne T320U optical gas filter correlation N2O analyzer (Fassbinder et al., 2013). The instrument is calibrated hourly using two reference gasses traceable to NIST standards. Mole fractions of CO2 are measured using an LI-820 infrared gas analyzer.Nitrate leaching will be assessed using lysimeters, which are already installed at the C2 pothole, and will be installed at the five remaining potholes to enable comprehensive monitoring of NO3- fluxes as a function of landscape position and management. Our zero-tension lysimeters consist of 8" diameter PVC pipes cut in half and filled with thoroughly washed quartz sand to maintain hydraulic conductivity with the surrounding soil. The pipes are capped and plumbed with fittings and tubing that drain to buried 2 L sample bottles. Lysimeters are manually installed by digging a soil pit to 0.6 m and carefully excavating a cavern into the upslope wall of the pit such that the top of the lysimeter is at 0.35 m and is fully covered by undisturbed soil. Then, the sample bottle is carefully buried as the pit is refilled, maintaining undisturbed soil around the lysimeter itself. A tube from the bottle to the soil surface allows complete evacuation of the sample bottle with a peristaltic pump operated by a portable electric drill (Kelso & Baker, 2016). Water samples will be collected on an event basis when field capacity is exceeded (i.e., whenever water accumulates in the bottles). Samples are filtered in the field through pre-combusted Whatman GF/F filters (0.7 µm) into acid-washed bottles and frozen prior to analysis of NO3- (Doane & Horwáth, 2003) and ammonium (NH4+, by phenol hypochlorite; (Weatherburn, 1967) in Hall's lab using a microplate spectrophotometer.Ponding depth and soil moisture will be measured using water level pressure transducers, which Co-PI Kaleita has installed at both sites for her related studies as briefly described above (Section A4.1). Pressure transducers will allow calculation of ponded area and depth of ponding when combined with high-resolution (~1 m) elevation data derived from Iowa's statewide LiDAR. Water level measurements will continue for the duration of this proposed project. We will thus be able to estimate pothole water infiltration using a simple water balance model, incorporating potential evapotranspiration calculated using data from a nearby meteorological station. We will also periodically measure near-surface (0-6 cm) soil moisture data using Theta probes (Delta-T Devices; calibration described in Kaleita et. al., 2005), with measurements made along the lysimeter transects.Objective 2 methods -We will apply AgroIBIS-VSF in a novel context the builds upon previous model development and evaluation to make quantitative estimates of the sub-field changes in production (and profitability) and ecosystem services of perennial production in potholes. The moisture/oxygen stress algorithm uses criteria based on hydrologic head whereby plant photosynthetic capacity is reduced by a piecewise stress factor (µi) between 1 (no stress) and 0 (total loss) as a function of hydrologic pressure head (h), based on the methods of Feddes et al. (1978) and as adapted by Soylu et al. (2014) for AgroIBIS-VSF, where hw, h*, hs and ha are the pressure heads at the wilting point, drought-induced incipient stomata closure point, oxygen stress threshold point above which oxygen stress conditions exist, and the anaerobiosis point, respectively. This algorithm has already been calibrated and tested for corn (Soylu et al., 2014; Zipper et al., 2015) and miscanthus parameters have already been calibrated for the points where moisture is below hs (VanLoocke et al., 2010, 2012, 2017). In this work, we will calibrate the moisture stress algorithm parameters for miscanthus based on data from the field project (Obj. 1). We will also use historical yield monitor data from the Been site, which has been collected over the last 10 years; this data will also continue to be collected during the current project.C3.2 Objective 3 MethodsFirst we will enhance PEWI's function by integrating project and other knowledge to add a miscanthus land-use type to the model and redesigning PEWI's nitrogen module to account for nitrogen loss through N2O emissions in addition to NO3-. Currently, the model can account for constructed and restored wetlands, riparian buffers, vegetative filters, and alternative agricultural land uses (e.g., rotational grazing, perennial bioenergy crop production). Ecosystem function and decision making related to potholes is already incorporated into PEWI through base data and user maps on soil drainage class and "strategic wetland areas," which include both potholes and impoundments within the riparian corridor (Fig. 8). Next we will enhance PEWI's version 3 by integrating text and videos explaining potholes and the miscanthus land use type, and to develop a specific educational modules focused on production and other ecosystem service tradeoffs associated with potholes. Version 3 of PEWI will be released in July/August 2017 and includes all of the functionality associated with the currently published Version 2, and expands upon it by integrating text and videos that explain and depict the land use types and science modules to provide a more seamless education and extension tool. Finally, we will design and implement a workshop to test and improve the effectiveness of using of PEWI with adult agricultural decision-makers, followed by broader dissemination and use of PEWI. Three workshops (funded by PD VanLoocke's startup funds) composed of 5-8 farmers and farmland owners will be co-hosted with state watershed coordinators already working across Iowa. Effectiveness will be assessed by surveying participants prior to and directly after the workshop and 6 months thereafter to assess improvements in participants' understanding of scientific concepts related to ecosystem function, tradeoffs between agricultural production and ecosystem services in farmed potholes, and alternative management options. Information gathered from participants will be used to refine workshop protocols, which will be made freely available on the inter­net, along with the PEWI model (www.nrem.iastate.edu/pewi).

Progress 04/01/18 to 03/31/23

Outputs
Target Audience:This research is targeted toward the continuum of people involved in managing farmland in US Corn Belt. This includes farmers, farming cooperatives, private companies, conservation officers, land owners, and Non-Governmental Organizations (e.g Practical Farmers of Iowa). Our research will help identify best management practices and influence the implementation of conservation programs. This work will serve farming communities through the identification of profitability in alternative managements as well as surrounding communities that will use water from agricultural river basins and watersheds. Changes/Problems: Outreach events were canceled due to COVID-19. Due to the on-going uncertainty around the pandemic, future events will likely be delayed. Our plan is to do an in-person event as soon as we can. The staff person conducting the simulations for Objective 2 was hired into a private sector position. This led to a delay in the modeling analysis during the final year. Fortunately we have hired a new student who is supported through a Iowa State University College of Agriculture Fellowship/Scholarship. They have been trained on the model and are now continuing this work and will complete it over the next year. What opportunities for training and professional development has the project provided?A PhD student (Nathan Lawrence; Ecology Evolution and Organismal Biology - Supervised by Steven Hall) was trained on agro-ecological and soil science techniques required for green house gas and soil water analysis. Nathan is now an Ecosystem Scientist for the Savana Institute (https://www.savannainstitute.org/staff-nate-lawrence/). A PhD student (Richard Magala, Wildlife Ecology - Supervised by Lisa Schulte) is being trained in agro-ecology, outreach and education and the use of PEWI. An MS student (Alex Steiner; Agronomy - Supervised by Emily Heaton) was trained in crop physiology techniques and crop modeling. A MS student (Brady Nahkala; Agricultural Engineering - Supervised by Amy Kaleita) was trained on water quality sampling, geographical information science (GIS) and web design and is now a Water Resources Design Engineer at Bolton & Menk, Inc. A research scientist (Patrick Edmonds) was trained in crop physiology and crop modeling and is now the Environmental Modeling Lead at Sustainable Environmental Consultants (https://sustainableenviro.com/). A postdoc (Shal-Al Emran, Crop Sciences, University of Illinois) is being trained in remote sensing, geographical information science (GIS), and crop physiology. A MS student (Destiny Williams, Agricultural Meteorology,- Supervised by Andy VanLoocke) is being trained in geographical information science (GIS) and crop modeling. Two undergraduate students are being cross trained by the graduate students mentioned above. All students are being trained on written and oral communication to both scientific and non-scientific audiences. These students will be involved in the outreach activities in Objective 3 and will have professional development opportunities associated with travel to professional/scientific meetings. How have the results been disseminated to communities of interest?Overall this funding has supported 8 peer reviewed manuscripts and at least 3 more are in mature stages of preparation. It also supported 3 graduate thesis that are posted publicly (https://www.lib.iastate.edu/research-tools/research-help/find-dissertations) and 2 conference proceedings abstracts and 8 scientific presentations. Our results have also been disseminated to the public via the below media products. Iowa State University College of Engineering News - 12/17/2020 "Pothole research to improve water quality" https://news.engineering.iastate.edu/2020/12/17/pothole-research-to-improve-water-quality/ Successful Farming - 7/8/2019 "Farming prairie potholes" https://www.agriculture.com/podcast/successful-farming-radio-podcast/farming-prairie-potholes Iowa Farmer Today - 8/23/2018 "Scientists examine perennial grass for flood-prone land" o https://www.agupdate.com/agriview/news/crop/scientists-examine-perennial-grass-for-flood-prone-land/article_5141a7cb-136b-5d83-a7fb-58a56bcabb9c.html News.iastate.edu - 7/31/2018 "Iowa State University scientists examine perennial grass as an option for flood-prone land" o https://www.news.iastate.edu/news/2018/07/31/miscanthuspothole What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Farmed potholes are agro-ecological 'hot spots' characterized by low-lying poorly drained sub-field regions that are disproptionality vunerable to loss of ecosytem services with climate variability. As climate patterns become increasingly variable, farmed potholes will become even more exposed to risk. It is therefore critical to provide new strategies for land managers to improve the ecosystem services of these sub-field features. Planting perennial grasses in farmed potholes could provide an option to farmers that is lower risk due to higher tolerance/resiliance to flooding and a key advantage of perennials is that once they are established, farmers will have much less management activities that will be interupted by the frequent ponding that occurs in potholes.The results of this study will provide critical information and an updated publically available education and outreach to assist in assessing improvements to ecosystem services associated with perenialization of pothole production. 1) Major activities completed / experiments conducted: Two publications were completed, Hall et al., 2023 and Huang et al., 2023 under this objective. N2O data were analyzed, with the primary activity related to separating transect locations and samples between those that had living miscanthus growing nearby and those where miscanthus had been killed by standing water.Water levels and biomass yields from objective one are being used to update the ponding stress Agro-IBIS parameters. To simulate a point model in a 3-D pothole, a programming wrapper was developed whereby a grid of simulations is created for each pothole. Approximately 100 simulations are being conducted per pothole and then output is stitched into a spatially extrapolated map of the pothole. Simulations were completed for one of the potholes at the site. We used a set of historical weather as well as a series of hypothetical climate change scenarios. Modeled biomass was then summed for the pothole of interest for both miscanthus and corn/soy model runs and then converted into an estimate of profit using cost estimates from Iowa State University Extension calculators. 2) Data collected: Biomass was assessed in 2020, the planting year and again in 2022, the maturation year. Aboveground biomass from Miscanthus plots was estimated by cutting stems at 0.1-m above the soil surface. 3) Summary statistics and discussion of results: Nitrogen leaching - Hall et a., 2023 - Analysis of the Nitrogen leaching (NO3 -and NH4 + ) transects indicated a strong topographic influence on nitrogen leaching. While Nitrogen leaching varied substantially between the observed potholes, upland portions of the transects had a median leaching rate approximately 55 kg N-N ha-1yr-1 less than the lowland portions of their respective potholes. When comparing the miscanthus Nitrogen leaching totals to the annual potholes, leaching rates were lower for miscanthus compared to the annual systems. Of note rates were more similar between systems in the establishment year (2019) but by the second year (2020) rates were notably lower in the miscanthus potholes. When comparing nitrogen leaching across the miscanthus potholes, leaching rates were inversely related to the miscanthus establishment quality, with lower rates occurring in potholes that were nearly completely filled with standing miscanthus, and higher rates occurring in the pothole where there was some die off of miscanthus due to flooding in the deepest portions. Soil organic carbon - Huang et al., 2023 - We used a combination of soil organic carbon measurements, soil inorganic carbon measurements (i.e. carbonate) and carbon isotope measurements of the stable isotope d13C to identify the amount and potential sources of soil carbon in the potholes. The measurements indicated that a the accumulation of carbon was largely driven by soil erosion from higher topographic positions rather than from the suppression of respiration due to high water content and low oxygen levels in low lying areas. Further analysis confirmed that a larger portion of the carbon in low lying areas was derived by natural mixed grassland carbon from pre cultivated plant growth, when compared to the higher topographic positions which had substantially more carbon inputs from corn and soybeans. Nitrous oxide emissions - We collected nitrous oxide emissions from the same transect locations where water quality was measured as mentioned above. Measurements were taken in 2018, 2019 and 2020. Our analysis indicates that corn and soybean potholes averaged approximately 8 kg N-N ha-1yr-1 and 4 kg N-N ha-1yr-1 respectively, while miscanthus averaged approximately 1 kg N-N ha-1yr-1. Also miscanthus N2O emissions decreased significantly from the establishment year (2019) to the first full year of growth. Decreasing from approximately 2 kg N-N ha-1yr-1 to 0.2 kg N-N ha-1yr-1. Biomass yields and Profit - - We collected biomass data were collected following the description above and then scaled by statistically relating ground measurements to satellite imagery from Planet. Profit was then calculated by subtracting production costs from biomass revenue following the approach in Edmonds et al., 2021. Our analysis indicated that all three of the monitored potholes were profitable in 2022 despite some areas of patchiness. The Plume pothole had the highest yields at 17.6 t/ha and the greatest profit of 774 $/ha, Hen was the deepest pothole, but performed the second best at 15.4 t/ha and $699, and the Cardinal pothole achieved 14.8 t/ha for a profit of 602 $/ha. Simulations from the first more idealized experiment agreed well with historical observations of corn and soybean yields in the case study pothole. With similar areas of zero yield occurring in the lowest portions of the pothole during most years. As was observed, this area expanded to larger portions of the pothole in wetter years. The model also agreed well with observations in the driest year, where the center of the pothole had near normal yields. The miscanthus simulations indicated that under most years, miscanthus would produce yield for a larger portion of the pothole than would corn and soybeans. However, our simulations also predicted portions of the pothole may still produce zero yield under miscanthus. 4) Key outcomes or other accomplishments realized: Intermittently flooded soils, such as prairie potholes have been hypothesized to produce much more N2O emissions than the surrounding landscape. The spatial trends of N2O emission across the transect do not find that intermittently flooded soils produce greater N2O than adjacent uplands. Of note, this finding was reported in a publication in the Proceedings of the National Academy of Sciences Overall the findings from the field experiment portion of this work suggest that miscanthus would produce more biomass, and generate more profit while losing less nitrogen to waterways and the atmosphere. We have also found evidence that unlike corn and soybeans, miscanthus can survive long durations of standing water (the threshold of which has not been surpassed thus far). However, similar to corn and soybeans, if the depth of water surpasses the total height of the canopy as it did in the deepest portions of the potholes in 2019, miscanthus will die. In subsequent years the death of plants has been confirmed as no re-emergence has occurred and the drowned out areas remain free of miscanthus.Overall across the pothole study area and across climate scenarios, modeled miscanthus production consistently exceeded corn and soybean. Overall our profitability analysis indicated that miscanthus would produce more profit over the course of 30 years.

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: VanLoocke, A., Hall S.J., Heaton, E., Kaleita, A.L., Schulte Moore, L., Soupir, M., Emran, S.A., Steiner A., Lawrence, N., Tenesaca, C.G., Edmonds, P., Boersma, N. (2022, December). An investigation of miscanthus production as potential climate-smart agricultural practice in fields that flood frequently In AGU Fall Meeting 2022. AGU.
• Type: Journal Articles Status: Published Year Published: 2023 Citation: Hall, S. J., Tenesaca, C. G., Lawrence, N. C., Green, D. I., Helmers, M. J., Crumpton, W. G., ... & VanLoocke, A. (2023). Poorly drained depressions can be hotspots of nutrient leaching from agricultural soils.
• Type: Journal Articles Status: Published Year Published: 2023 Citation: Huang, W., Mirabito, A. J., Tenesaca, C. G., Mejia-Garcia, W. F., Lawrence, N. C., Kaleita, A. L., ... & Hall, S. J. (2023). Controls on organic and inorganic soil carbon in poorly drained agricultural soils with subsurface drainage. Biogeochemistry, 163(2), 121-137.

Progress 04/01/21 to 03/31/22

Outputs
Target Audience:This research is targeted toward the continuum of people involved in managing farmland in the US Corn Belt. This includes farmers, farming cooperatives, private companies, conservation officers, land owners, and Non-Governmental Organizations (e.g. Practical Farmers of Iowa). Our research will help identify best management practices and influence the implementation of conservation programs. This work will serve farming communities through the identification of profitability in alternative managements as well as surrounding communities that will use water from agricultural river basins and watersheds. Changes/Problems:Outreach events were canceled due to COVID-19. Due to the on-going uncertainty around the pandemic, future events will likely be delayed. Our plan is to do an in-person event as soon as we can, however this may occur beyond the reporting period. What opportunities for training and professional development has the project provided?A Ph.D. student (Nathan Lawrence; Ecology Evolution and Organismal Biology - Supervised by Steven Hall) is being trained on agro-ecological and soil science techniques required for greenhouse gas and soil water analysis. A Ph.D. student (Richard Magala, Wildlife Ecology - Supervised by Lisa Schulte) is being trained in agro-ecology, outreach and education, and the use of PEWI. An MS student (Alex Steiner; Agronomy - Supervised by Emily Heaton) is being trained in crop physiology techniques and crop modeling. An MS student (Brady Nahkala; Agricultural Engineering - Supervised by Amy Kaleita) is being trained on water quality sampling, geographical information science (GIS), and web design. Two undergraduate students are being cross-trained by the graduate students mentioned above. All students are being trained in written and oral communication to both scientific and non-scientific audiences. These students were involved in the outreach activities in Objective 3 and will have professional development opportunities associated with travel to professional/scientific meetings. How have the results been disseminated to communities of interest?Our results have now been shared through several publications and research presentations at professional meetings (see products for details). We also conducted a survey of 21 students at Iowa State University who were a part of a two-week discussion on water quality challenges in Iowa. The survey participants were asked reflective questions about how their use of PEWI helped them learn and make decisions about land use and water quality. That report is available upon request and will be published as an appendix to Richard Magala's Thesis. We have also shared our results via the media and outreach: Iowa State University College of Engineering News - 12/17/2020 "Pothole research to improve water quality" https://news.engineering.iastate.edu/2020/12/17/pothole-research-to-improve-water-quality/ Successful Farming - 7/8/2019 "Farming prairie potholes" https://www.agriculture.com/podcast/successful-farming-radio-podcast/farming-prairie-potholes Iowa Farmer Today - 8/23/2018 "Scientists examine perennial grass for flood-prone land" https://www.agupdate.com/agriview/news/crop/scientists-examine-perennial-grass-for-flood-prone-land/article_5141a7cb-136b-5d83-a7fb-58a56bcabb9c.html News.iastate.edu - 7/31/2018 "Iowa State University scientists examine perennial grass as an option for flood-prone land" https://www.news.iastate.edu/news/2018/07/31/miscanthuspothole What do you plan to do during the next reporting period to accomplish the goals?Next year we will continue to follow the timeline provided in the original poster. We will complete the analysis of measurements of the ecosystem services metrics described in Objective 1 during the first 2 years of Miscanthus growth. We will also continue to monitor weather variables and ponding depths in the potholes. Data collection for the soil chamber and lysimeter data collection is now complete and analysis of years 2 and 3 data is nearly complete. The primary focus of the Objective 1 work will be complete a manuscript describing the differences in ecosystem services between miscanthus and corn/soybean in potholes We also plan to continue work on improving the calibration of Agro-IBIS that was published earlier under Objective 2. This includes quality control the soil and elevation grids needed to simulate miscanthus, corn and soybeans in the potholes. We will continue our model parameterization using the data from the first two full growing seasons and plan to prepare a publication with the updated code, but this may occur outside the funding period. For Objective 3 we will finalize the updates to PEWI soil C and GHG modules and prepare a publication describing the results. This will include the results of the literature review and model simulations.

Impacts
What was accomplished under these goals? Objective 1. 1) Major activities completed / experiments conducted: Data analysis of the previously described data was the primary focus of this year's activity. Data collection is complete, however some passive monitoring continues to occur at the site. 2) Data collected: No new data to report. 3) Summary statistics and discussion of results: Analysis of the Nitrogen leaching (NO3-and NH4+) transects indicated a strong topographic influence on nitrogen leaching. While Nitrogen leaching varied substantially between the observed potholes, upland portions of the transects had a median leaching rate approximately 55 kg N-N ha-1yr-1less than the lowland portions of their respective potholes. When comparing the miscanthus Nitrogen leaching totals to the annual potholes, leaching rates were lower for miscanthus compared to the annual systems. Of note rates were moresimilar between systems in the establishment year (2019) but by the second year (2020) rates were notably lower in the miscanthus potholes. When comparing nitrogen leaching across the miscanthus potholes, leaching rates were inversely related to the miscanthus establishment quality, with lower rates occurring in potholes that were nearly completely filled with standing miscanthus, and higher rates occurring in the pothole where there was some die off of miscanthus due to flooding in the deepest portions. 4) Key outcomes or other accomplishments realized: Previous estimates of soil greenhouse gas emissions frequently cite the Intergovernmental Panel on Climate Change emission factor method that assumes 1-2% of N inputs and N recycled through crop biomass will be emitted as N2O. Our automated chamber results suggest an average emission factor of 4% in corn/soybean systems. Intermittently flooded soils, such as prairie potholes have been hypothesized to produce much more N2O emissions than the surrounding landscape. The spatial trends of N2O emission across the transect do not find that intermittently flooded soils produce greater N2O than adjacent uplands. Of note, this finding was reported in a publication in the Proceedings of the National Academy of Sciences. Overall the findings from the field experiment portion of this work suggest that miscanthus would produce more biomass, and generate more profit while losing less nitrogen to waterways and the atmosphere. We have also found evidence that unlike corn and soybeans, miscanthus can survive long durations of standing water (the threshold of which has not been surpassed thus far). However similar to corn and soybeans, if the depth of water surpasses the total height of the canopy as it did in the deepest portions of the potholes in 2019, miscanthus will die. In subsequent years the death of plants has been confirmed as no re-emergence has occurred and the drowned out areas remain free of miscanthus. Objective 2. 1) Major activities completed / experiments conducted: Ponding depths across each of the monitored potholes and biomass transects are now being converted into input files for the Agro-IBIS simulations. This process will allow for the representation of the standing water and the quantification of its impact on maize and miscanthus biomass production. Water levels and biomass yields from objective one are being used to update the ponding stress Agro-IBIS parameters. While the process analyzing and data and conducting the model calibration is ongoing, we decided to proceed with a version of the model based on the few existing parameterizations for miscanthus in the literature. To simulate a point model in a 3-D pothole, a programming wrapper was developed whereby a grid of simulations is created for each pothole. Approximately 100 simulations are being conducted per pothole and then output is stitched into a spatially extrapolated map of the pothole. Simulations were completed for one of the potholes at the site. We used a set of historical weather as well as a series of hypothetical climate change scenarios. These scenarios were not explicitly derived from climate models, but were intended to represent the shifts in precipitation patterns that those models have consistently predicted. Briefly the scenarios contained different shifts in precipitation patterns, with varying amounts of shifting from heavy spring precipitation and while conserving total precipitation with dryer summertime totals. Modeled biomass was then summed for the pothole of interest for both miscanthus and corn/soy model runs and then converted into an estimate of profit using cost estimates from Iowa State University Extension calculators. 2) Data collected: No new data to report. 3) Summary statistics and discussion of results:Simulations from the first more idealized experiment agreed well with historical observations of corn and soybean yields in the case study pothole. With similar areas of zero yield occurring in the lowest portions of the pothole during most years. As was observed, this area expanded to larger portions of the pothole in wetter years. The model also agreed well with observations in the driest year, where the center of the pothole had near normal yields. The miscanthus simulations indicated that under most years, miscanthus would produce yield for a larger portion of the pothole than would corn and soybeans. However our simulations also predicted portions of the pothole may still produce zero yield under miscanthus. 4) Key outcomes or other accomplishments realized:Overall across the pothole study area and across climate scenarios, modeled miscanthus production consistently exceeded corn and soybean. Overall our profitability analysis indicated that miscanthus would produce more profit over the course of 30 years. While we are continuing to work toward an updated model parameterization using the data collected in Objective 1, we successfully created a prototype modeling framework and published the analysis in Global Change Biology Bioenergy. To our knowledge this is the first such agro-ecosystem model that has been adapted to represent spatially explicit crop growth in a dynamically flooding landscape. Objective 3 1) Major activities completed / experiments conducted: The work in Objective 3 was focused on continuing to increase the capabilities of the updated version of PEWI.A new student, Richard Maalawas brought on and was trained on the updated version of PEWI.He is updating the soil carbon storage and adding a GHG module. As a part of his GHG module work he is doing a model comparison between two cropping and biogeochemical models, DNDC and APSIM. Because neither model is able to simulate all of PEWI's land uses, we are using a combination. He's making the comparison for land uses can be simulated with both. 2) Data collected: Soil carbon data form the Morrow plots at the University of Illinois, the longest continuous running agronomic experiment in North America, was collectedto calibrate APSIM SOC model output.Validation data were collected from the Cropping Systems Coordinated Agricultural Project (CSCAP): Climate Change, Mitigation, and Adaptation in Corn-based Cropping Systems; or Sustainable Corn CAP. Because the empirical data from field experiments does not represent all of the relevant management options needed to populate the data tables in PEWI, Some numbers not available from the literature so APSIM and DNDC were pursued. A literature review of GHG emissions and emission factors for annual and perennial plants has been conducted and the analysis of those data are ongoing. 3) Summary statistics and discussion of results:See work plan for next reporting period. 4) Key outcomes or other accomplishments realized:In year 4, Richard Magala was trained on PEWI and is now an expert user who is able to update the PEWI Carbon Sequestration module in progress and is in the process of developing a new Greenhouse Gas Emissions module for PEWI.

Publications

• Type: Journal Articles Status: Published Year Published: 2021 Citation: Edmonds PM, Franz K, Heaton EA, Kalieta A, Hall SJ, VanLoocke A (2021). A Comparison of Conventional Annual and Alternative Perennial Cropping Systems Under Contemporary and Future Precipitation Scenarios in the US Prairie Pothole Region. Global Change Biology  Bioenergy. 13 (9), 1481-1497
• Type: Journal Articles Status: Published Year Published: 2022 Citation: Nahkala, B., A. Kaleita, M. Soupir, and A. VanLoocke. (2022) Prairie Pothole Management Support Tool: A web application for evaluating prairie pothole flood risk Agrosystems, Geosciences & Environment 5 (2), e20280
• Type: Other Status: Other Year Published: 2022 Citation: Learning about ecosystem service tradeoff with PEWI: Student Reflections
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Lawrence, N. C., Tenesaca, C. G., VanLoocke, A., & Hall, S. J. (2021). Nitrous oxide emissions from agricultural soils challenge climate sustainability in the US Corn Belt. Proceedings of the National Academy of Sciences, 118(46), e2112108118.
• Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Tenesaca, C. G., Helmers, M. J., Crumpton, W. G., Heaton, E., VanLoocke, A., & Hall, S. J. (2021, December). Cropped Depressions: Sources or Sinks of Leached Nutrients in Tile-Drained Agricultural Soils?. In AGU Fall Meeting 2021. AGU.
• Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: How Scale and Scaling Matter in the Pursuit of Ecosystem Services in the Bioeconomywith a FEW Examples. A VanLoocke, K Ferin, L Chen, T Hartman, YY Lee& - AGU Fall Meeting 2021, 2021

Progress 04/01/20 to 03/31/21

Outputs
Target Audience:This research is targeted toward the continuum of people involved in managing farmland in US Corn Belt. This includes farmers, farming cooperatives, private companies, conservation officers, land owners, and Non-Governmental Organizations (e.g Practical Farmers of Iowa). Changes/Problems:Outreach events were canceled due to COVID-19. Due to the on-going uncertainty around the pandemic, future events will likely be delayed. Our plan is to do an in-person event as soon as we can. What opportunities for training and professional development has the project provided?A PhD student (Nathan Lawrence; Ecology Evolution and Organismal Biology - Supervised by Steven Hall) is being trained on agro-ecological and soil science techniques required for green house gas and soil water analysis. A PhD student (Richard Magala, Wildlife Ecology - Supervised by Lisa Schulte) is being trained in agro-ecology, outreach and education and the use of PEWI. An MS student (Alex Steiner; Agronomy - Supervised by Emily Heaton) is being trained in crop physiology techniques and crop modeling. A MS student (Brady Nahkala; Agricultural Engineering - Supervised by Amy Kaleita) is being trained on water quality sampling, geographical information science (GIS) and web design. Two undergraduate students are being cross trained by the graduate students mentioned above. All students are being trained on written and oral communication to both scientific and non-scientific audiences. These students will be involved in the outreach activities in Objective 3 and will have professional development opportunities associated with travel to professional/scientific meetings. How have the results been disseminated to communities of interest?Iowa State University College of Engineering News - 12/17/2020 "Pothole research to improve water quality" https://news.engineering.iastate.edu/2020/12/17/pothole-research-to-improve-water-quality Successful Farming - 7/8/2019 "Farming prarire potholes" https://www.agriculture.com/podcast/successful-farming-radio- podcast/farming-prairie-potholes Iowa Farmer Today - 8/23/2018 "Scientists examine perennial grass for flood-prone land" https://www.agupdate.com/agriview/news/crop/scientists-examine-perennial-grass-for-flood-prone-land/article_5141a7cb-136b-5d83-a7fb-58a56bcabb9c.html News.iastate.edu - 7/31/2018 "Iowa State University scientists examine perennial grass as an option for flood-prone land" https://www.news.iastate.edu/news/2018/07/31/miscanthuspothole Kaleita, A., Heaton, E., Vanloocke, A., Hall, S., Soupir, M., Martin, A., Upadhyay, P., Edmonds, P., and Nahkala, B. 2019. Characterization and Management of Cropped Depressional Wetlands in the Prairie Pothole Region. Poster presented at the Annual Meeting of the American Ecological Engineering Society, Asheville, NC, June 2019. What do you plan to do during the next reporting period to accomplish the goals?Next year we will continue to follow the timeline provided in the original poster. We will wrap up the measurements of the ecosystem services metrics described in Objective 1 during the first 2 years of Miscanthus growth. We will also continue to monitor weather variables and ponding depths in the potholes. Data collection for the soil chamber and lysimeter data collection is now complete and partially analyzed years 2 and 3 data will be analyzed and written up in year 4. Work will continue on Objective 2 to initialize model simulations in preparation for the data collected in Objective 1. This includes quality control the soil and elevation grids needed to simulate miscanthus, corn and soybeans in the potholes. We will continue our model parameterization using the data from the first two full growing seasons, however the parameterization will not be complete until we have subsequent data from subsequent growing seasons. We will hold outreach events with the public where applicable and begin planning for the on-site field days that will occur the following year.

Impacts
What was accomplished under these goals? IMPACT:Our research will help identify best management practices and influence the implementation of conservation programs. This work will serve farming communities through the identification of profitability in alternative managements as well as surrounding communities that will use water from agricultural river basins and watersheds. Objective 1:Quantify biomass production, profitability, soil nitrous oxide (N2O) and carbon dioxide (CO2) emissions, and NO3-leaching under conventional corn/soybean systems versus miscanthus in farmed potholes. 1)In addition to the automated transects, a total of six manually monitored transects were established in May 2018 in the pothole described above and in five additional potholes (two in conventional management and two that were transitioned to miscanthus in May 2019). 10 plots were established along each transect from pothole to surrounding upland. Greenhouse gases (CO2, CH4, and N2O) were monitored with manual, non-steady state chambers on weekly to bi-weekly intervals when soils were not frozen. Infiltration of nitrate (NO3-) and ammonium (NH4+) was quantified at each plot with flow-through resin lysimeters installed at a depth of 35 cm. Lysimeters were removed, analyzed, and reinstalled annually. Manual transects were monitored through Fall, 2020. 2) Gas exchange measurements were also collected along the transect and include photosynthetic response to internal CO2 concentration (i.e. A-Ci) curves as well as instantaneous photosynthesis and stomatal conductance measurements. Summary statistics and discussion of results: In the maize plants sampled, there was a reduction of CO2-saturated rate of photosynthesis (Vpr) as elevation increased, a pattern which was not observed in miscanthus. Miscanthus assimilation (A) by stomatal conductance was not affected by the elevation sampling location. Key outcomes or other accomplishments realized.Our analysis in objective 2 will quantify and characterize this impact. These results indicate that potholes should be targeted for management that reduces N infiltration. Objective 2: Assess changes in ecosystem services provided by growing miscanthus in farmed potholes in the Midwest US; 1) This process will allow for the representation of the standing water and the quantification of its impact on maize and miscanthus biomass production. Water levels and biomass yields from objective one are being used to update the ponding stress Agro-IBIS parameters. To simulate a point model in a 3-D pothole, a programming wrapper was developed whereby a grid of simulations is created for each pothole. Approximately 100 simulations are being conducted per pothole and then output is stitched into a spatially extrapolated map of the pothole. 2) Other data collected include weather, soils and topography data for each of the pothole plots. One weather file has been created and will be updated with 2021 weather upon the completion of that calendar year. Weather data are being collected from a combination of local weather stations all within 0.5 to 5 km from the research site. Soils data are being accessed from the GSSURGO data base and adjusted based on soil cores (from another project) when available. Key parameters include the hydraulic conductivity and soil organic matter composition. Topography data are being assembled from the state of Iowa 3m Lidar topographic data base. The personnel and framework are in place for this objective. Initial model simulations have been conducted and a process is in place to generate results for allo f the potholes of interest. This will take place in the coming year. Objective 3: Facilitate support for the strategic adoption of low risk/high reward perennial systems by farmers, farmland owners, and their advisors for the joint production of food, bioenergy, and ecosystem services from prairie pothole landscapes. In year 3, we successfully recruited a new student, Richard Magala, for PhD work in Wildlife Ecology. Update of PEWI Carbon Sequestration module in progress and we are in the process of developing a new Greenhouse Gas Emissions module for PEWI.

Publications

• Type: Journal Articles Status: Published Year Published: 2020 Citation: Chennault, CM, RM Valek, JC Tyndall, LA Schulte. 2020. PEWI: An interactive web-based ecosystem services model designed for a broad public audience. Ecological Modelling 431:109165.
• Type: Websites Status: Published Year Published: 2020 Citation: https://crops.extension.iastate.edu/blog/danielle-m-clark-wilson-emily-heaton-tyler-donovan/farmed-prairie-potholes
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Lawrence, Nathaniel C., and Steven J. Hall. "Capturing temporal heterogeneity in soil nitrous oxide fluxes with a robust and low-cost automated chamber apparatus." Atmospheric Measurement Techniques 13.7 (2020): 4065-4078.
• Type: Journal Articles Status: Under Review Year Published: 2021 Citation: Edmonds, Patrick; Franz, Kristie; Heaton, Emily; Kaleita, Amy; Soupir, Michelle; VanLoocke, Andy, Planting miscanthus instead of row crops may increase the productivity and economic performance of farmed potholes

Progress 04/01/19 to 03/31/20

Outputs
Target Audience:This research is targeted toward the continuum of people involved in managing farmland in US Corn Belt. This includes farmers, farming cooperatives, private companies, conservation officers, land owners, and Non-Governmental Organizations (e.g Practical Farmers of Iowa). Our research will help identify best management practices and influence the implementation of conservation programs. This work will serve farming communities through the identification of profitability in alternative managements as well as surrounding communities that will use water from agricultural river basins and watersheds. Changes/Problems:As of the submission of this report there are no major changes associated with the Covid-19 pandemic during the reporting period. Going into the next reporting period, some field activites and nearly all outreach activities will be impacted. We will follow the guidlines established by the CDC, national, state, local and University authorities. Where possible we will move to delivering some of our outreach content online if restrictions extend beyond the next reporting period. What opportunities for training and professional development has the project provided?A PhD student (Nathan Lawrence; Ecology Evolution and Organismal Biology - Supervised by Steven Hall) is being trained on agro-ecological and soil science techniques required for green house gas and soil water analysis. A PhD student (Alex Steiner; Agronomy - Supervised by Emily Heaton) is being trained in crop physiology techniques and crop modeling. An MS student (Brady Nahkala; Agricultural Engineering - Supervised by Amy Kaleita) is being trained on water quality sampling, geographical information science (GIS) and web design. Two undergraduate students are being cross trained by the graduate students mentioned above. All students are being trained on written and oral communication to both scientific and non-scientific audiences. These students will be involved in the outreach activities in Objective 3 and will have professional development opportunities associated with travel to professional/scientific meetings. How have the results been disseminated to communities of interest?Iowa Farmer Today - 8/23/2018 "Scientists examine perennial grass for flood-prone land" https://www.agupdate.com/agriview/news/crop/scientists-examine-perennial-grass-for-flood-prone-land/article_5141a7cb-136b-5d83-a7fb-58a56bcabb9c.html News.iastate.edu - 7/31/2018 "Iowa State University scientists examine perennial grass as an option for flood-prone land" https://www.news.iastate.edu/news/2018/07/31/miscanthuspothole Kaleita, A., Heaton, E., Vanloocke, A., Hall, S., Soupir, M., Martin, A., Upadhyay, P., Edmonds, P., and Nahkala, B. 2019. Characterization and Management of Cropped Depressional Wetlands in the Prairie Pothole Region. Poster presented at the Annual Meeting of the American Ecological Engineering Society, Asheville, NC, June 2019. What do you plan to do during the next reporting period to accomplish the goals?Next year we will continue to follow the timeline provided in the original poster. We will continue the measurements of the ecosystem services metrics described in Objective 1 during the first year of Miscanthus growth. We will also continue to monitor weather variables and ponding depths in the potholes. Work will begin to initialize model simulations in preparation for the data collected in Objective 1. This includes creating the soil and elevation grids needed to simulate miscanthus, corn and soybeans in the potholes. We will begin our model parameterization using the data from the first full growing season, however the parameterization will not be complete until we have subsequent data from subsequent growing seasons. We will hold outreach events with the public where applicable and begin planning for the on-site field days that will occur the following year.

Impacts
What was accomplished under these goals? Objective 1: Major activities completed / experiments conducted: In May 2019 a transect was established along the elevation gradient at each of three miscanthus managed potholes. Eight sampling points were established along the transect, evenly spaced by elevation for height and leaf area index (LAI) measurements during the growing season. Height and LAI measurements were also taken from a non-flooded miscanthus plot control, planted in the same year, approximately 1.6 km away. In addition to the automated transects, a total of six manually monitored transects were established in May 2018 in the two potholes described above and in four additional potholes (two in conventional management and two that were transitioned to miscanthus in May 2019). 10 plots were established along each transect from pothole to surrounding upland. Greenhouse gases (CO2, CH4, and N2O) are monitored with manual, non-steady state chambers on weekly to bi-weekly intervals when soils are not frozen. Infiltration of nitrate (NO3-) and ammonium (NH4+) is quantified at each plot with flow-through resin lysimeters installed at a depth of 35 cm. Lysimeters are removed, analyzed, and reinstalled annually. Data collected: We also collected baseline data (conventional management) on inundation patterns in the Miscanthus plots in spring 2018, as well as continuing to collect inundation data in the conventional plots, which we began monitoring through other projects in 2016. These data are collected using a pressure transducer installed in a stilling well at the lowest elevation in each pothole, the signals from which are then converted to ponded water depth. Data are collected every 15 minutes from approximately the data of planting until just prior to corn/soybean harvest. Starting in June of 2019 plant height and LAI were measured throughout the growing season at each point along the miscanthus transects, and in the control plot. Summary statistics and discussion of results: Total N2O emissions from our automated conventional transect averaged 14.95 and 7.12 kg N-N2O-ha-1yr-1 with fertilizer application accompanying corn management in 2017 and 2019 respectively and 4.04 kg N-N2O-ha-1yr-1 in soybean management in 2018.Miscanthus plots averaged 6.07 kg N-N2O-ha-1yr-1. N leaching rates from corresponding zero-tension lysimeter results average 25 kg-N ha-1yr- in 2017 and 11 kg-N ha-1yr- in 2018. Manually sampled transect lysimeters are currently being analyzed. The average miscanthus plant height increase with the elevation from 55 cm at the bottom the potholes to 155 cm at the top. The height of the miscanthus in the control was measured at 225 cm. The LAI at the bottom of the potholes during the growing season averaged to 0.095 m2m-2 and 0.523 m2m-2 at the top. The average at LAI in the control plots was 1.296 m2m-2 Key outcomes or other accomplishments realized: Miscanthus was successfully established in our three experimental pothole regions. There was widespread ground cover in areas where above-ground shoots of miscanthus were not below water for significant periods of time (i.e. days). Portions of the pothole that experienced standing water had good ground cover but less than the control plot which experienced little or no ponding. Thus far, cropping type has not impacted N2O emission rates but this could become more apparent as the miscanthus establishes. N leaching rates quantified with zero-tension lysimeters were highest in the frequently flooded lowest three plots of the transect (56 kg-N ha-1yr-1 vs 24 kg-N ha-1yr-1). These results indicate that potholes should be targeted for management that reduces N infiltration.Previous estimates of soil greenhouse gas emissions frequently cite the Intergovernmental Panel on Climate Change emission factor method that assumes 1-2% of N inputs will be emitted as N2O. Our automated chamber results suggest an average emission factor of 8.7%, 5.6, and 4.2% for 2017,2018, and 2019 respectively. Objective 2: Major activities completed / experiments conducted: Agro-IBIS simulations were conducted on a 9x9m grid with spatially explicit soil conditions and hourly water depths recorded in the pothole. Simulations were conducted for a corn/soybean rotation and miscanthus. Each species was parameterized using data available from the literature. Model simulations included a historical period for model evaluation as well as a series of future scenarios intended to quantify the impact of shifting precipitation patterns. Data collected: Site specific management and weather data were collected for the site for a 12-year period. Yield monitor data from combine harvester were assembled. Observations of corn leaf area index from one of the previous cropped years were also assembled. Historical production costs of revenue rates were assembled. Published values for the growth reduction and termination of soybean, corn and miscanthus were collected to parameterize Agro-IBIS. Climate scenario files were generated using historical precipitation records and modifying precipitation patterns to account for projected changes. Summary statistics and discussion of results: Simulations indicated that the majority of the pothole would have total losses of corn and soybeans in the majority of the simulated historical years. This compared well with yield monitor observations. Our simulations also indicated that a smaller portion of the pothole would have complete loses for miscanthus, depending on the set of assumptions included in our excess water parameterization. Simulations of future precipitation patterns indicated that the area of total loss and pothole average yields would decrease for all three species, corn, soybean and miscanthus. However losses were significantly smaller for miscanthus. Key outcomes or other accomplishments realized: A framework and protocol for assessing the ecosystem services of farmed potholes was created. Initial simulations were for a single pothole at our field site and indicated that miscanthus would perform better than the corn/soybean rotation for the majority of the pothole area over the majority of years in our case study. We will build on this outcome to generate estimates for a broader area/set of potholes in the next project year. Objective 3: Major activities completed / experiments conducted: Literature review and initial code development to support this decision making through the online PEWI tool was completed in 2019 by PhD student Robert Valek and a team of six undergraduate/MS-level developers; these individuals were supported through funds provided by the USDA NIFA McIntire-Stennis program (CRIS project #IOW05534). Through this grant a new MS student has been hired to complete debugging and beta testing of PEWI v4, which will include a new economics module to support strategic adoption of low risk/high reward perennial systems by farmers, farmland owners, and their advisors for the joint production of food, bioenergy, and ecosystem services. We expect to release PEWI v4 in 2020. Data collected: Data collection associated with yield, environmental performance, and enterprise budgets for all the land uses currently simulated through PEWI has been supported through other funding: conventional corn, conservation corn, conventional soybean, conservation soybean, mixed fruits and vegetables, alfalfa hay, grass hay, switchgrass, continuous grazed pasture, rotationally grazed pasture, conventional forest, conservation forest, short-rotation woody bioenergy, prairie, and wetland. As Miscanthus data associated with this grant are collected, they will be integrated into the existing PEWI frameworks and a new Miscanthus land use will be incorporated into PEWI. Summary statistics and discussion of results: N/A Key outcomes or other accomplishments realized: Three papers were submitted to review. One has been published, one is being revised for the journal it was submitted to, and the third is under review.

Publications

• Type: Journal Articles Status: Published Year Published: 2019 Citation: Martin, A.R., M.L. Soupir, A.L. Kaleita, 2019. Seasonal and intra-event nutrient levels in farmed prairie potholes of the Des Moines Lobe. Transactions of the ASABE. 62(6): 1607-1617. DOI: 10.13031/trans.13414.
• Type: Other Status: Other Year Published: 2020 Citation: Chennault, CM, RM Valek, LA Schulte, JC Tyndall. In revision. PEWI: An interactive web-based ecosystem services model designed for a broad public audience. Ecological Modelling.
• Type: Journal Articles Status: Under Review Year Published: 2020 Citation: Grudens-Schuck, N, LA Schulte. In review. Teaching about land use and watersheds with PEWI. Getting Into Soil and Water.
• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Nahkala, B, et. Al, 2019. Characterization and Management of Depressional Wetlands in the Prairie Pothole Region. Poster presented at the 2019 Annual Meeting of the American Ecological Engineering Society, June 2019, Asheville, NC USA
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Martin, A.R., A.L. Kaleita, M.L. Soupir, 2019. Inundation patterns of farmed pothole depressions with varying subsurface drainage. Transactions of the ASABE 62(6): 1579-1590. DOI: 10.13031/trans.13435.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Anderson, K, N Grudens-Schuck, R Valek, LA Schulte, SW Smalley. 2020. Alignment of a digital watershed and land use game to national education standards. Journal of Natural Sciences Education. doi: https://doi.org/10.1002/nse2.20005
• Type: Journal Articles Status: Other Year Published: 2020 Citation: Edmonds PM, Franz K, Heaton EA, Kaleita A, Hall SJ, VanLoocke A. A Comparison of Conventional Annual and Alternative Perennial Cropping Systems Under Contemporary and Future Precipitation Scenarios in the US Prairie Pothole Region.
• Type: Journal Articles Status: Other Year Published: 2020 Citation: Lawrence N, Hall SJ, Tenesaca C. Nitrous oxide predictions underestimate direct emissions in a Midwest cropland

Progress 04/01/18 to 03/31/19

Outputs
Target Audience:This research is targeted toward the continuum of people involved in managing farmland in US Corn Belt.This includes farmers, farming cooperatives, private companies, conservation officers, land owners, and Non-Governmental Organizations (e.g Practical Farmers of Iowa). Our research will help identify best management practices and influence the implementation of conservation programs. This work will serve farming communities through the identification of profitability in alternative managements as well as surrounding communities that will use water from agricultural river basins and watersheds. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?A PhD student (Nathan Lawrence; Ecology Evolution and Organismal Biology - Supervised by Steven Hall) is being trained on agro-ecological and soil science techniques required for green house gas and soil water analysis. A PhD student (Alex Steiner; Agronomy - Supervised by Emily Heaton) is being trained in crop physiology techniques and crop modeling. A MS student (Brady Nahkala; Agricultural Engineering - Supervised by Amy Kaleita) is being trained on water quality sampling, geographical information science (GIS) and web design. Two undergraduate students are being cross trained by the graduate students mentioned above. All students are being trained on written and oral communication to both scientific and non-scientific audiences.These students will be involved in the outreach activities in Objective 3 and will have professional development opportunities associated with travel to professional/scientific meetings. How have the results been disseminated to communities of interest?The results from this project have been disseminated to the public, via popular press articles,and the scientific community via a journal article. Popular press articles: Iowa Farmer Today - 8/23/2018 "Scientists examine perennial grass for flood-prone land" https://www.agupdate.com/agriview/news/crop/scientists-examine-perennial-grass-for-flood-prone-land/article_5141a7cb-136b-5d83-a7fb-58a56bcabb9c.html News.iastate.edu - 7/31/2018 "Iowa State University scientists examine perennial grass as an option for flood-prone land" https://www.news.iastate.edu/news/2018/07/31/miscanthuspothole What do you plan to do during the next reporting period to accomplish the goals?Next year we will continue to follow the timeline provided in the original poster. We will continue the measurements of the ecosystem services metrics described in Objective 1 during the first year of Miscanthus growth. We will also continue to monitor weather variables and ponding depths in the potholes. Work will begin to initialize model simulations in preparation for the data collected in Objective 1. This includes creating the soil and elevation grids needed to simulate miscanthus, corn and soybeans in the potholes. We will begin our model parameterization using the data from the first full growing season, however the parameterization will not be complete until we have subsequent data from subsequent growing seasons. We will hold outreach events with the public where applicable and begin planning for the on-site field days that will occur the following year.

Impacts
What was accomplished under these goals? Farmed potholes are agro-ecological 'hot spots' characterized by low-lying poorly drained sub-field regions that are disproptionality vunerable to loss of ecosytem services with climate variability.The annual row crops that are typically planted in these features are highly suseptable to excess moisture stress from ponding, causing economic losses and environmental impacts. As climate patterns become increasingly variable, farmed potholes will become even more exposed to risk. It is therefore critical to provide new strategies for land managers to improve the ecosystem services of these sub-field features.There is evidence to suggest that planting perennial grasses in farmed potholes could provide an option to farmers that is lower risk due to higher tolerance/resiliance to flooding. Also,a key advantage of perennials is that once they are established, farmers will have much less management activities that will be interupted by the frequent ponding that occurs in potholes.Farmland covered with an actively growing crop, that is taking up nutirents and holding soil in place is very likely to have better environmental perfomacne than one without a crop. The objective of this study is to examine changes in key processes dictating the ecosystem services of replacing current cropping systems with a more moisture resilient perennial bioenergy crop (Miscanthus) within farmed potholes in the US Corn Belt.To achieve this, we will compare paired farmed pothole biomass production, farm-scale profitability, greenhouse gas balance, and water quality (nitrate leaching) for miscanthus to current corn/soy cropping systems.We will improve a recently developed and tested pothole version of the agroecosystem model, Agro-IBIS which can be used to produce estimates of these ecosystem services for a range of socio-economic/climate scenarios by combining a spatially explicit probablistic subfiled profit analysis and refined the miscanthus algorithm.The results of this study will provide critical information and an updated publically available education and outreach tool ,PEWI, to assist in assessing interactions between human and phyisical dimentiosn associated with improvements to ecosystem services associated with perenialization of pothole production. Our research will help identify best management practices and influence the implementation of conservation programs. This work will serve farming communities through the identification of profitability in alternative managements as well as surrounding communities that will use water from agricultural river basins and watersheds. Objective 1:Quantify biomass production, profitability, soil nitrous oxide (N2O) and carbon dioxide (CO2) emissions, and NO3-leaching under conventional corn/soybean systems versus miscanthus in farmed potholes; 1) A replicate transect was established in October 2018 in a pothole that was transitioned from conventional management to miscanthus in May 2019. The miscanthus block encompasses the topographically lowest 5 of 8 plots on the transect. Soil sampling began at the replicate transect in April 2019. Stand counts are being conducted in each of six potholes and canopy coverage will be measured using a portable leaf area meter during the 2019 growing season. 2) We also collected baseline data (conventional management) on inundation patterns in the Miscanthus plots in spring 2018, as well as continuing to collect inundation data in the conventional plots, which we began monitoring through other projects in 2016. These data are collected using a pressure transducer installed in a stilling well at the lowest elevation in each pothole, the signals from which are then converted to ponded water depth. Data are collected every 15 minutes from approximately the data of planting until just prior to corn/soybean harvest. 3) Total N2O emissions from our automated conventional transect averaged 14.95 kg N-N2O-ha-1yr-1 with fertilizer application accompanying corn management in 2017 and 4.04 kg N-N2O-ha-1yr-1 in soybean management in 2018. N leaching rates from corresponding zero-tension lysimeter results average 25 kg-N ha-1yr- in 2017 and 11 kg-N ha-1yr- in 2018. Results for miscanthus management are not yet available. Manually sampled transect lysimeters are currently being analyzed. 4) A total of two transect-years of automated data, two transect-years of corresponding zero-tension lysimeter data, and six transect years of manual data have been collected. Comparison between cropping types is not yet possible as miscanthus was planted in May 2019. N leaching rates quantified with zero-tension lysimeters were highest in the frequently flooded lowest three plots of the transect (56 kg-N ha-1yr-1 vs 24 kg-N ha-1yr-1). These results indicate that potholes should be targeted for management that reduces N infiltration. Objective 2: Assess changes in ecosystem services provided by growing miscanthus in farmed potholes in the Midwest US; Student hired. Objective 3: Facilitate support for the strategic adoption of low risk/high reward perennial systems by farmers, farmland owners, and their advisors for the joint production of food, bioenergy, and ecosystem services from prairie pothole landscapes. Work on objective 3 has not yet begun.

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Kaleita, A., Heaton, E., Vanloocke, A., Hall, S., Soupir, M., Martin, A., Upadhyay, P., Edmonds, P., and Nahkala, B. 2019. Characterization and Management of Cropped Depressional Wetlands in the Prairie Pothole Region. Poster presented at the Annual Meeting of the American Ecological Engineering Society, Asheville, NC, June 2019.