Duration: 10/01/2026 to 09/30/2031

Administrative Advisor(s):

NIFA Reps:

Non-Technical Summary

Nitrogen fertilizer is essential for corn production across the United States, yet it also causes some of the most significant environmental challenges in agriculture. Too much nitrogen can contaminate groundwater, contribute to algal blooms and hypoxia in waterways, and release nitrous oxide—a potent heat-trapping gas—from farm fields. Meanwhile, farmers face rising fertilizer costs and increasing uncertainty from weather variability, making it difficult to determine how much nitrogen crops actually need. Improving nitrogen use in corn-based systems is therefore critical for farm profitability, food security, and environmental protection.

 The goal of this multistate project is to develop better nitrogen management strategies that help farmers apply the right amount of nitrogen at the right time, from the right source, and in the right place. To achieve this, the project will (1) study how soils, microbes, fertilizers, and organic amendments such as manure supply nitrogen under different conditions; (2) test and refine technologies that can improve in-season nitrogen recommendations; and (3) translate these findings into practical recommendation tools, decision aids, and educational resources that farmers and advisors can use across the Corn Belt.

 The primary audiences include farmers, crop consultants, agribusinesses, conservation professionals, and state and federal agencies. These groups will benefit from more accurate nitrogen recommendations, reduced input costs, higher nitrogen use efficiency, and improved environmental outcomes. By combining field research, laboratory studies, modeling, and extension, this project will generate science-based tools that help farmers maintain high yields while protecting water quality and reducing nitrogen losses to the environment.

Statement of Issues and Justification

Stakeholder need: nitrogen, food, and environment

Nitrogen (N) fertilizer has been one of the most transformative inputs in human history. Since the development of the Haber–Bosch process, synthetic N has enabled a massive expansion of food production, supporting population growth and global economic development. It is estimated that nearly 40% of the global population would not be alive today without synthetic fertilizer (Smil, 2001a), and approximately half of current global food production depends on it (Smil, 2001b, 2011). In the United States, corn production dominates fertilizer N use; more N fertilizer is applied to corn than to all other crops combined (Simons et al., 2014). Corn serves not only as a staple crop for food and livestock feed but also as a critical feedstock for renewable fuels and industrial products, making it central to agricultural profitability and national food and energy security.

Stakeholders, including farmers, agribusiness, crop consultants, policymakers, and conservation groups, consistently identify efficient N management in corn-based cropping systems as a top priority (Houlton et al., 2013). Nitrogen fertilizer is an expensive input, usually second only to seed in corn production. At present, producers face tremendous uncertainty in making N fertilizer decisions. Weather variability, soil type, organic matter levels, crop rotation history, and manure applications all influence how much N is available to crops and how much is lost through leaching, denitrification, or volatilization (Sierra, 1997; Fernández et al., 2017; Yi et al., 2023; Li et al., 2024; Liao et al., 2024). Fertilizer must be applied well before the period of peak crop demand, and the inherent unpredictability of in-season rainfall and mineralization creates pressure to over-apply fertilizer as “insurance” against yield loss. This strategy often reduces profitability and increases environmental damage (Hong et al., 2007; Shcherbak et al., 2014; Miller et al., 2020; Lu et al., 2022).

Producers, commodity groups, and conservation organizations are calling for more precise N management recommendations and decision tools that account for spatial and temporal variability in soil N supply and crop demand. For example, in 2023, 30 farmers, crop advisors, scientists and other agricultural stakeholders in Iowa attended a three-day event to design a new tool to support N fertilizer rate decisions. Stakeholders seek guidance that integrates diverse N sources, including animal manures, green manures, and cover crops, while also leveraging modern innovations such as enhanced efficiency fertilizers, remote sensing, and precision agriculture technologies (Morris et al., 2018). Without continued research and coordinated multi-state efforts, inefficiencies in N use will persist, undermining farm profitability, degrading water quality, and contributing to agricultural nitrogenous emissions.

Importance of improving N use in the U.S.

The paradox of N fertilizer is that it is simultaneously indispensable for food security and one of the most problematic environmental pollutants. Nitrogen is an essential input for sustaining crop yields in intensive systems; without it, U.S. agriculture could not meet the demand for feed, food, and fuel derived from corn-based systems. Yet the unintended consequences of N use are among the greatest environmental challenges facing agriculture (Aneja et al., 2009; Sutton et al., 2011a). Excess nitrate leaching contaminates groundwater and surface water, increasing health risks and water treatment costs (Houlton et al., 2019). Drainage from the Corn Belt contributes heavily to hypoxia in the Gulf of Mexico and other coastal systems, where algal blooms and oxygen depletion harm aquatic life and reduce fisheries productivity (Burkart and James, 1999; Rabalaiset al., 2002; Conley et al., 2011; Guo et al., 2020). In the atmosphere, agriculture is now the single largest source of nitrous oxide (N₂O), a radiatively active gas with ~300 times the heat-trapping capacity of carbon dioxide and the leading ozone-depleting emission of the 21st century (Davidson, 2009; Ravishankara et al., 2009; USEPA, 2021; Lu et al., 2022).

In addition, ammonia and nitrogen oxides released from agricultural systems contribute to the formation of secondary particulate matter, a major component of PM_2.5 pollution with well-documented impacts on air quality and human respiratory health (Warneck, 1999; Baek et al., 2004; Aneja et al., 2009). Reactive N deposition further exacerbates environmental stress through regional haze, reduced visibility, and ecosystem acidification, linking agricultural N losses directly to widespread air quality and ecological concerns (Sutton et al., 2009; Sutton et al., 2011b).

If progress is not made, the consequences are clear: stagnating N use efficiency (NUE), uncompetitive farm profitability, and escalating environmental costs borne by farmers, communities, and ecosystems (Sutton et al., 2011a). Such outcomes are unsustainable and will likely lead to more stringent regulation of nutrient inputs, increasing production costs and constraining management flexibility. Conversely, the potential benefits of advancing N management are substantial. Research demonstrates that improved understanding of soil N mineralization, better accounting for cover crop effects, and more precise fertilizer timing can sustain or even increase yields while reducing nutrient losses (Scharf et al., 2006b; Shapiro and Wortmann, 2006; McDaniel et al., 2020). Thus, improved N management offers one of the most effective avenues for agriculture to simultaneously enhance economic returns and reduce its environmental footprint.

Weather uncertainty further heightens the urgency of improving N use in the U.S. In the Corn Belt, overall precipitation is projected to rise modestly, but with a disproportionate increase in the frequency and intensity of extreme rainfall events during spring and early summer (Kellner and Niyogi, 2015). These shifts accelerate N losses through leaching and denitrification and contribute to downstream nitrogenous emissions in aquatic systems (Bowles et al., 2018). Greater weather variability also increases the unpredictability of soil N mineralization, complicating recommendations and reducing the reliability of traditional management strategies (Yi et al., 2023). Without adaptation, producers face heightened risks of yield loss, increased environmental impacts, and intensified regulatory scrutiny.

Technical feasibility: current knowledge of N-cycle processes and their management

This research is technically feasible due to recent advances in agronomy, soil science, microbiology, and precision agriculture, combined with the demonstrated capacity of NC1195 members to execute large, multi-state projects. While the fundamental biological underpinnings of the N cycle are well described, major gaps remain in quantifying and predicting how these processes interact under real-world field conditions. For example, soil organic matter and manure mineralization can supply a substantial fraction of crop N needs, but the timing and magnitude of this release vary with temperature, moisture, oxygen, and management history  (Sierra, 1997; Lynch, 2013; Yan et al., 2020; Klein et al., 2025). Overlooking these dynamics often leads to over-application of fertilizer N. In addition, fertilizer inputs themselves can stimulate soil organic N mineralization through “priming effects,” yet most recommendation systems do not account for this feedback (Jenkinson et al., 1985; Mahal et al., 2019; Haas et al., 2024).

Conservation practices present both opportunities and trade-offs. Cereal rye cover crops, for example, are effective at reducing nitrate leaching, but they can also increase N₂O emissions or depress subsequent corn yields if not carefully managed (Scharf and Alley, 1988; Mamo et al., 2003). Recent multi-state research led by NC1195 members demonstrates that yield drag of up to 10% or more can occur in corn following cereal rye, even when terminated two weeks before planting, highlighting the need for deeper understanding of these mechanisms (Preza-Fontes et al., 2022; Acharya et al., 2017). In addition, multi-state research led by NC1195 members estimated that corn following cereal rye needs an additional ~50 lb N/acre than corn following no cover crop or a legume cover crop (Rawal et al., in prep). Key unresolved questions include what regulates soil N-supplying power, whether cover crops improve or worsen the N₂O emission balance, and what factors drive the yield penalties often observed following cover crops. Addressing these questions requires integrated approaches that link soil health, microbial dynamics, and cropping system design. At the same time, new technologies offer unprecedented opportunities for precision management. Enhanced efficiency fertilizers, nitrification and urease inhibitors, and alternative N sources such as anaerobic digestate solids and processed manure products are increasingly being tested for their ability to improve NUE and reduce losses (Mirabilia et al., 2025; under review). Remote sensing tools, UAV platforms, and crop canopy sensors now enable real-time monitoring of crop N status across spatially variable landscapes (Ciampitti and Vyn, 2011). Biosensor-based diagnostics developed and deployed by NC1195 members have provided growers with real-time, spatially sensitive data to support adaptive management. These tools have already been integrated into on-farm research, extension programs, and training for farmers and crop advisors, demonstrating both feasibility and impact. Similarly, the Nitrogen Fertilizer Application Consultation Tool (NFACT), launched in 2025, provides over 21,000 scenario-specific estimates of optimum N rates using field trial data and calibrated crop models. Together, these innovations show that decision-support systems are maturing into practical tools for widespread adoption.

The NC1195 group has repeatedly demonstrated capacity to carry out this type of research and outreach. Past collaborations have clarified spatial variability in N response (Scharf et al., 2005; Scharf et al., 2006a; Scharf et al., 2006b; Laboski et al., 2008), changes in the economic optimum N rate over time (Baum et al. 2025), quantified interactions between fertilizer and manure (McDaniel et al., 2020), and advanced the science of soil health and its relationship to C and N cycling (Canisares et al., 2021; Studt et al., 2021; McDaniel and Middleton, 2024; Keiser et al., 2025). Ongoing work has shown how past management, such as repeated manure applications, alters root C allocation and stabilization (Keiser et al., 2025), and how perennializing systems or integrating livestock can improve soil health and reduce N losses (Carey et al., 2025; Moore et al., 2025; Yi et al., 2025). Collectively, the group members’ expertise in agronomy, soil microbiology, modeling, and extension, coupled with proven success in developing and deploying decision-support tools, demonstrates that the proposed research is both technically feasible and poised to deliver transformative outcomes for N management across the Corn Belt.

Advantages of a multistate effort: regional project goals

Nitrogen management challenges are not confined to any single state. The soils, climate, cropping systems, and manure management practices of the Corn Belt are diverse, and results from a single location rarely apply across the region. A multistate effort is therefore essential to develop recommendations and tools that are broadly relevant and widely adopted.

The NC1195 project has a strong record of leveraging regional collaboration to produce impactful outcomes. Multistate experiments and data syntheses have shown that the “optimal” N rate can vary not only between states but within fields, depending on soil properties and rainfall patterns (Mamo et al., 2003; Scharf et al., 2005). By pooling data across environments, the group members have produced recommendations that are more robust and defensible than those from isolated studies. The regional nature of this work ensures that findings are not skewed by local anomalies and that recommendations capture the full spectrum of management and environmental variability.

Equally important is the breadth of expertise within the committee. Soil scientists, agronomists, microbiologists, ecologists, modelers, and extension specialists bring complementary perspectives, enabling a systems-level approach to N management. The collaboration also provides unique opportunities to test emerging technologies, such as remote sensing and enhanced efficiency fertilizers, across diverse conditions. Extension and outreach specialists within the group ensure rapid dissemination of findings to producers, crop advisors, and policymakers. The strength of this multistate network is one of the project’s greatest assets, allowing it to deliver outcomes with both scientific rigor and practical relevance.

Potential impact

The renewal of NC1195 will deliver measurable advances in both agricultural productivity and environmental stewardship. By improving understanding of soil, manure, and fertilizer N dynamics, the project will help synchronize N supply with crop demand. This tighter alignment will lead directly to improvements in NUE, allowing producers to apply less fertilizer without sacrificing yield. More accurate recommendations will reduce the reliance on blanket application strategies, lowering input costs while improving profitability across the Corn Belt.

Environmental benefits will follow from these efficiency gains. With better accounting of soil and manure N contributions, fewer excess nutrients will escape into water bodies, reducing nitrate leaching and improving groundwater quality. At the same time, decreasing fertilizer over-application and adopting more targeted management practices will reduce atmospheric N emissions. Together, these outcomes represent a substantial step toward reconciling agricultural productivity with environmental sustainability.

Another key impact of the project will be the development of innovative decision-support tools. By integrating remote sensing, crop canopy sensors, UAV imagery, and predictive modeling, the committee will provide producers and advisors with in-season guidance to adjust N applications. These tools will give farmers confidence to reduce “insurance N” while maintaining yield stability, particularly under variable weather conditions. The incorporation of precision agriculture technologies into practical recommendations will help translate research advances into real-world improvements at the farm level. Finally, the renewal will strengthen the extension and outreach capacity of the committee. By developing educational materials, training programs, and regionally validated recommendations, NC1195 will ensure rapid dissemination of research outcomes to farmers, advisors, policymakers, and conservation professionals. This strong extension component will accelerate adoption of best practices and contribute to broader nutrient management initiatives across the region. Beyond the Corn Belt, the project’s integrated approach will serve as a model for sustainable N management in other intensive cropping systems worldwide.

Related, Current and Previous Work

Management practices and optimum nitrogen use

Over the past several decades, agronomists and soil scientists have worked to refine N management recommendations to maximize yield and profitability while reducing negative environmental outcomes. Early recommendation systems often relied on simple yield-goal formulas, where expected crop yield was multiplied by a fixed N factor to calculate fertilizer needs (Morris et al., 2018). Although easy to use, these approaches ignored variability across soils, weather, and management conditions, often leading to over- or under-application.

More recently, several Midwestern states have adopted the Maximum Return to Nitrogen (MRTN) approach, which uses multi-year, multi-site datasets of yield response trials to identify rates that maximize profitability (Sawyer et al., 2006). MRTN represented a major step forward, but it remains relatively static, relying on aggregated data rather than dynamic environmental predictors. NC1195 members have been at the forefront of both developing MRTN and identifying its limitations.

Research by Tremblay et al. (2012) demonstrated that soil texture and rainfall strongly influence crop response to N, while Puntel et al. (2019) identified soil depth, soil nitrate at planting, residue cover, and heat stress around silking as key predictors of the economic optimum N rate (EONR). Baum et al. (2025) recently documented that optimum N rates are trending upward across the Midwest, reflecting increased yield potential and shifts in climate. These findings underscore the need for updated recommendations that adapt to changing conditions.

Importantly, NC 1195 members are continuing to conduct multi-state field trials that generate the empirical datasets underpinning MRTN and related decision systems (Collier et al., 2017) (Iowa Nitrogen Initiative: https://www.agron.iastate.edu/portfolio/iowa-nitrogen-initiative/). These trials are essential for understanding spatial and temporal variability in N response and ensuring recommendations remain relevant.

A newer frontier for NC1195 is investigating the synergistic effects of N with other critical resources such as sulfur, water, and organic amendments. Current research includes evaluating corn yield responses to sulfur fertilization at specific N rates following cover crops, as well as broader studies of N × sulfur interactions across diverse environments. Additional projects are examining how drainage systems and irrigation regimes affect crop response to applied N, reflecting the strong influence of water management on fertilizer efficiency. Complementary work is advancing understanding of manure applications in silage corn systems, where mineralization dynamics, timing of nutrient release, and interactions with fertilizer N are critical for aligning supply with crop demand and minimizing environmental losses. Collectively, these studies highlight the need for integrated approaches, recognizing that effective N recommendations cannot be made in isolation but must account for interactions among N, other nutrients, water management, and organic inputs to optimize yield, profitability, and environmental outcomes.

Innovative tools and diagnostics

A defining strength of NC1195 has been its contributions to the development and testing of N diagnostic and decision tools. Earlier committee work included adaptation of hand-held chlorophyll meters and canopy reflectance sensors for predicting in-season N needs (Scharf et al., 2006a; Hawkins et al., 2007; Scharf et al., 2011; Li et al., 2016; Khanal et al., 2018). These technologies provided proof of concept that plant-based sensing could inform adaptive fertilization. More recently, attention has shifted toward soil biological and health-based indicators of N-supplying capacity. Promising metrics include permanganate-oxidizable carbon, mineralizable carbon, soil protein assays, and CO₂ burst tests (Culman et al., 2012; Hurisso et al., 2018; Yostet al., 2018). McDaniel et al. (2020) showed that combining a 14-day aerobic mineralization assay with fixed ammonium extraction significantly improved the prediction of non-responsive sites compared with the pre-sidedress nitrate test. Building on this work, McDaniel & Middleton (2024) demonstrated that applying NRCS “soil health principles” increased multiple ecosystem services, while Carey et al. (2025) and Moore et al. (2025) provided evidence that livestock integration improves both soil health and productivity. Prairie strips have also been shown to enhance soil health indicators after nearly a decade of adoption (Dutter et al., 2025). These results suggest that soil health diagnostics can be linked to improved prediction of crop N response.

Perhaps the most transformative recent development is the release of the Nitrogen Fertilizer Application Consultation Tool (NFACT) in 2025. NFACT integrates trial-based benchmarking with process-based cropping system models to provide more than 21,000 scenario-specific N recommendations. Farmers can compare their own practices to regional trial data and explore how variables such as crop rotation, planting window, soil nitrate, weather, and price ratios affect optimum N rates. Because the tool is continually updated with new Iowa Nitrogen Initiative trial data, it provides a living, educational resource for both producers and advisors. In parallel, NC1195 members are developing biosensor-based diagnostics for in-season crop N status. These tools provide real-time, spatially sensitive measurements that are being deployed in demonstration sites and multi-stakeholder extension programs. Training programs for NRCS and Extension staff are being developed to accelerate adoption. Members of our group have also applied machine learning approaches to integrate soil, weather, and management data into predictive models of the economic optimum N rate of corn (Qin et al., 2018; Zhen et al., 2025; Ransom et al., 2023; Shao et al., 2023). Collectively, these innovations reflect NC1195’s continued leadership in diagnostics and decision support.

Soil health, biological processes, and plant available N

Predicting plant-available N (PAN) from soil organic matter, manure, and cover crops remains one of the central challenges in crop N management. While nitrate and ammonium are the primary forms of N taken up by crops, organic N cycling through mineralization and immobilization plays a critical role in determining supply (Wade et al., 2016; Miller and Geisseler, 2018; Geisseler et al., 2021). Because these processes are strongly influenced by microbial communities, soil carbon pools, and management history, they remain difficult to predict reliably.

NC1195 members have contributed substantially to this area during the current cycle. Keiser et al. (2025) showed that historical swine manure applications altered belowground carbon allocation, changing the proportion stabilized in mineral-associated organic matter. Studt et al. (2021) and Flater et al. (in prep) found that perennializing agriculture with miscanthus or rye reduced nitrate leaching losses. Yi et al. (2025) reported that diversified cropping systems enhanced soil N supply despite limited carbon accrual. Villarino et al. (2025) evaluated nutrient release from anaerobic digestate solids, illustrating how organic amendments affect nutrient cycling. Collectively, these findings demonstrate how management history and system diversification shape soil health and N dynamics. Cover crops remain a focus of NC1195 research. While widely promoted as a solution to nutrient leaching, meta-analyses show mixed impacts on N₂O emissions, with cover crops sometimes increasing and sometimes decreasing emissions relative to no-cover controls (Basche et al., 2014). Cereal rye, in particular, has been associated with corn yield drag exceeding 10% in some studies (Pantoja et al., 2015). Termination two or more weeks before planting helps but does not eliminate this effect. NC1195 members are directly investigating the drivers of yield drag following cereal rye cover crops and exploring management strategies to mitigate it.

At the same time, members are leading collaborative studies on cropping system strategies to decrease N₂O emissions. Hanna Poffenbarger, Mike Castellano, and Andrew Margenot are collaborating on projects that test the use of cover crops and early soybean planting as a way to reduce emissions. These projects illustrate the committee’s ability to address both agronomic and environmental outcomes through systems-level research.

Together, this body of work highlights key unresolved questions for the next cycle: (1) what regulates soil N-supplying power and how it can be enhanced, (2) whether cover crops reliably reduce or exacerbate nitrogenous emissions in Midwest systems, and (3) the biological and agronomic mechanisms driving corn yield drag after cover crops.

Decision-making tools and educational resources

Translation of scientific insights into practical tools has always been a strength of NC1195. The MRTN system itself was a major committee outcome (Sawyer et al., 2006). More recently, members have refined soil-test and canopy-based recommendations (Bean et al., 2018; Clark et al., 2019) and tested the integration of soil and weather data into models. Economic evaluations are now a priority. Ransom et al. (2020) found that while few N decision tools were tightly correlated with EONR, most generated similar profitability outcomes, suggesting that adoption depends on usability and robustness across environments. During this cycle, NC1195 members expanded these evaluations, examining both economic and environmental trade-offs. For example, Villarino et al. (2025) analyzed nutrient release and greenhouse gas implications of digestate amendments, while Lee et al. (2025) demonstrated that legacy and contemporary N inputs shape nitrogenous and carbon gas emissions in maize and miscanthus soils. Menegaz et al. (2022) took a comprehensive look at N sources and time of application in terms of economic and environmental loss (nitrate, nitrous oxide, and ammonia) outcomes.

Members are also developing outreach infrastructure to accelerate adoption. Biosensor diagnostics and UAV imagery are being deployed in on-farm demonstration networks, while targeted trainings are being designed for NRCS and Extension personnel. The NFACT platform is already serving as both an educational tool and decision aid, helping farmers and advisors visualize variability in N response.

Since the previous project cycle, NC1195 members have advanced research on the synergistic effects of N with other resources such as sulfur and water, broadened investigations of new N sources including enhanced efficiency fertilizers, manures, and nanoparticle formulations, and developed cropping system strategies to reduce nitrogenous emissions and yield drag from cover crops. The committee has also delivered new decision-support platforms like NFACT, biosensor-based diagnostics, and machine learning models, while expanding outreach through on-farm demonstrations and training. 

This strong track record demonstrates that NC1195 has consistently delivered on its objectives. At the same time, critical knowledge gaps remain. With its unique combination of field trials, diagnostics development, modeling, and extension, NC1195 is well positioned in the next cycle to continue generating actionable knowledge and tools that enhance crop productivity, farmer profitability, and environmental stewardship across the Corn Belt.

Remaining challenges and research needs

Despite decades of research, fundamental knowledge gaps remain that limit progress in N management for corn-based systems. First, while soil and plant diagnostics have improved, our ability to predict soil N-supplying power under diverse management and climate scenarios remains poor, largely because mineralization and immobilization are highly variable and influenced by historical management, weather, and microbial processes (Wade et al., 2016; Miller & Geisseler, 2018; McDaniel et al., 2020). Second, synergistic interactions between N and other resources, such as sulfur, water, and drainage, are not well integrated into current recommendation systems, despite evidence that they strongly affect crop N responses and environmental losses (Tremblay et al., 2012; Puntel et al., 2019). Third, while cover crops and other conservation practices can reduce nitrate leaching, their impacts on nitrogenous emissions, subsequent crop yield, and N fertilizer needs of the subsequent crop remain inconsistent, with persistent challenges such as cereal rye–induced yield drag (Pantoja et al., 2015; Lee et al., 2025). Finally, decision-support systems such as MRTN and NFACT represent major advances, but they still fall short in capturing field-specific variability, particularly under extreme weather events projected with climate change (Kellner & Niyogi, 2015; Baum et al., 2025). These knowledge gaps directly motivate the proposed objectives outlined below.

Objectives

1. Investigate N availability and microbial N transformations from a variety of N sources (e.g., enhanced efficiency fertilizers, conventional fertilizers, animal manures, green manures) in a range of environmental conditions and management scenarios.
   
2. Develop and evaluate precision agriculture technologies, remote-sensing, data-driven tools, and models to improve N fertilizer management.
   
3. Translate field and laboratory research into actionable N management tools and educational resources to enhance profitability and sustainability in corn-based cropping systems
   

Methods

To accomplish the proposed objectives, NC1195 members will employ a coordinated set of field, laboratory, and modeling approaches that leverage the strengths of multiple states, disciplines, and institutions. Our methodology builds on the long history of shared N response trials and collaborative datasets within this committee and is designed to ensure that results are comparable across sites, statistically robust, and readily translatable into decision tools and extension products.

Objective 1: Investigate N availability and microbial N transformations from a variety of N sources

Field studies will be conducted across diverse edaphoclimatic settings to evaluate how corn responds to a range of N sources (e.g., conventional fertilizers, enhanced efficiency fertilizers, manures, green manures, and emerging inputs such as nanoparticles) under contrasting management systems. Representative examples include cover crop-based systems, alternative drainage designs, and irrigation management. Standardized soil characterization will be performed across sites, including both conventional nutrient analyses and soil health testing (e.g., mineralizable C, soil protein, permanganate oxidizable C), to enable cross-state comparison of soil N-supplying capacity.

Greenhouse and laboratory experiments will be used to complement field studies by providing controlled settings where mechanisms underlying field observations can be explored. These experiments allow us to test a wider range of soils, isolate specific N sources, and manipulate soil conditions that are difficult to control in the field, thereby enabling a deeper mechanistic understanding of microbial processes. Soil microbial biomass, activity, and community composition will be assessed from samples collected. Approaches will include chloroform fumigation-extraction, fatty acid methyl ester (FAME) analysis, extracellular enzyme assays, gas flux measurements, and molecular approaches (e.g., amplicon sequencing, functional gene quantification for N-cycling pathways). Several members will also employ ¹⁵N isotopic techniques, including ¹⁵N-labeled fertilizer tracing, ¹⁵N pool dilution, and ¹⁵N enrichment in cover crop residues, to quantify PAN release and N transformations across management systems. Functional metagenomics and structural equation modeling will be applied to link microbial processes to crop-available N and to identify management practices that improve NUE. The use of harmonized protocols across states will enable data pooling and meta-analysis.

Objective 2: Develop and evaluate precision agriculture technologies, remote sensing, and models

NC1195 group members will collaborate to expand and integrate N recommendation tools that incorporate soil properties, weather data, and management factors. One strategy is to combine existing trial data maintained by NC1195 members with geospatial data (soil, weather, management history) to build a large, multi-state meta-dataset. Multivariate regression and machine learning approaches will be employed to identify the most influential predictors of N response and to generate ex ante field-specific N recommendations.

A complementary strategy is the design of new multi-year, multi-location response trials that consistently collect both yield and yield-impacting covariates (e.g., soil nitrate, weather events, crop rotation, cover crop presence). This dataset will support fitting of advanced varying coefficient regression models, allowing both parametric and non-parametric approaches to explain spatial and temporal variability in EONR. UAV-based remote sensing, canopy reflectance sensors, and biosensors will also be tested and validated across states, with algorithms calibrated against both regional datasets and pooled multi-state observations. This collective dataset will allow for robust evaluation of precision agriculture technologies across soil, climate, and management gradients in the Corn Belt.

Objective 3: Translate research into actionable tools and educational resources

Findings from Objectives 1 and 2 will be summarized in the form of regionally calibrated N recommendation algorithms, decision-support platforms, and extension materials. Building on successes such as MRTN and the recently launched NFACT tool, the committee will jointly develop new algorithms that integrate weather, soil, and management information into recommendations. These will be tested across states and validated with farmer cooperators through on-farm trials.

 Educational resources will be co-produced across states, including extension bulletins, factsheets, and videos. Coordinated demonstration sites and field days will provide opportunities for producers and crop advisors to interact directly with committee members and to evaluate decision-support tools in practice. Members will also collaborate on training workshops for NRCS and Extension staff to accelerate adoption of new practices and technologies. 

Synthesis approach and coordination

The multistate design of this project is central to its success. By coordinating trial protocols across states, the committee will generate datasets that are larger, more diverse, and more robust than any single investigator could achieve. Data will be pooled for meta-analyses and modeling, with shared repositories enabling collaboration and reproducibility. Statistical analyses will include both traditional approaches (ANOVA, regression) and advanced methods (spatial statistics, multivariate analyses, structural equation modeling). By combining field experimentation, laboratory diagnostics, modeling, and extension, NC1195 will provide actionable, regionally relevant recommendations that improve NUE, enhance profitability, and reduce environmental impacts across the Corn Belt.

Measurement of Progress and Results

Outputs

• Refereed scientific publications Comments: Refereed scientific publications advancing fundamental understanding of nitrogen (N) cycling, microbial transformations, soil N-supplying power, and interactions between N and other resources such as sulfur and water. Committee members will continue their strong publication record in leading agronomy, soil science, and environmental journals
• Datasets and data products Comments: Datasets and data products including multi-year, multi-location N response trial data; pooled soil health and microbial community measurements; and integrated databases linking soils, weather, management, and crop response. These will be curated in ways that facilitate meta-analyses and model calibration across states
• Decision-support tools and algorithms Comments: Decision-support tools and algorithms including new recommendation models that incorporate soil, weather, and management variables; enhancements to existing platforms such as MRTN and NFACT; and testing of emerging diagnostics such as UAV imagery, biosensors, and machine learning approaches
• Educational and extension resources Comments: Educational and extension resources such as extension bulletins, factsheets, demonstration site data, training modules for NRCS and Extension personnel, and multimedia products (videos, webinars) targeting farmers and advisors
• Presentations to professional, policy, and farmer audiences Comments: Presentations to professional, policy, and farmer audiences through scientific conferences, workshops, and field days, ensuring rapid dissemination of results to both technical and non-technical stakeholders.

Outcomes or Projected Impacts

• Scientific advancement Publications and pooled analyses will advance mechanistic understanding of soil microbial N transformations, cover crop impacts on N₂O emissions and yield drag, and the regulation of soil N-supplying power under different management systems.
• Improved diagnostics and recommendations Farmers and advisors will have access to refined N decision tools that better capture spatial and temporal variability in crop N response, reducing uncertainty and “insurance N” applications
• Economic benefits By improving nitrogen use efficiency (NUE), these tools and recommendations will reduce input costs for farmers while sustaining or increasing yields, thereby improving profitability
• Environmental benefits Improved synchronization of N supply with crop demand will reduce nitrate leaching into groundwater and surface water, lowering risks of hypoxia and drinking water contamination. Reduced N₂O emissions will contribute to climate mitigation and ozone protection
• Workforce development and outreach impact Training programs for NRCS and Extension personnel will build institutional capacity, while demonstration sites and farmer cooperators will accelerate adoption of conservation practices
• Policy relevance By quantifying trade-offs and benefits of management practices, the committee’s work will inform state and federal nutrient management guidelines and climate-smart agriculture initiatives

Milestones

(2026):Organize committee members into sub-groups aligned with objectives (soil processes, diagnostics/modeling, decision tools/extension): Harmonize field and laboratory protocols for N response trials, soil health assessments, and microbial assays across states. Establish centralized data repositories for trial data, soil and weather covariates, and microbial analyses

(2027):Begin integration of soil, weather, and management data into meta-datasets: Conduct first round of pooled analyses linking microbial data and soil health indicators with crop N responses. Pilot biosensor diagnostics and UAV-based sensing at demonstration sites. Submit initial manuscripts on multi-state soil health and N response synthesis.

(2028):Release preliminary enhancements to N recommendation algorithms incorporating soil and weather predictors: Publish multi-state studies on cover crop yield drag mechanisms and nitrogenous emission trade-offs. Conduct workshops for NRCS and Extension personnel on emerging tools and recommendations

(2029):Refine decision-support tools (e.g., NFACT enhancements, machine learning models) using expanded datasets: Publish papers on interactions of N with sulfur, water, and other resources. Disseminate extension bulletins and videos summarizing practical recommendations for farmers and advisors. Conduct farmer/advisor surveys to assess adoption and usability of tools.

(2030):Summarize capstone multi-state analyses and decision-support outputs: Release final versions of new N recommendation algorithms and decision tools. Hold multi-state extension events and webinars to promote adoption. Compile a five-year accomplishments overview to inform potential future committee publications

Projected Participation

View Appendix E: Participation

Outreach Plan

NC1195 has a strong track record of outreach, supported by multiple members with formal Extension appointments and many others engaged in applied research and producer education. In the renewal cycle, outreach will remain a central focus, with coordinated efforts to ensure that research results are broadly disseminated, accessible, and actionable. Results will be communicated through multiple formats tailored to different audiences. For scientific and technical stakeholders, outputs will include refereed publications, conference presentations, and synthesis papers. For farmers, advisors, and policy audiences, committee members will prepare extension bulletins, newsletters, fact sheets, videos, and web-based resources. Interactive venues such as field days, demonstration plots, and workshops will provide opportunities for direct engagement, while webinars, podcasts, and farm press articles will expand access to those unable to attend in person. Several members maintain active websites and social media channels, which will be used to highlight project findings in real time.

Decision-support tools (e.g., MRTN enhancements, NFACT, biosensor diagnostics) will be emphasized as key outreach products. These will be co-developed with input from farmer cooperators and tested in on-farm trials to ensure usability. Training programs for NRCS, Extension personnel, and crop consultants will help scale adoption and build capacity across the region.

The project will also ensure equity in access to services and information. Outreach materials will be written in clear, accessible language, with translations provided where appropriate. Partnerships with Extension networks and conservation organizations will facilitate engagement with under-served farming communities, including minority, small-scale, and limited-resource producers who may benefit most from improved nutrient management. NC1195 outreach will be tightly integrated with other multistate and national initiatives focused on nutrient management, soil health, and climate-smart agriculture. By sharing findings across states, pooling extension materials, and co-hosting workshops and webinars, the committee will maximize its impact and ensure that stakeholders across the Corn Belt and beyond have equal access to the tools and knowledge needed to improve nitrogen management.

Organization/Governance

The Technical Committee will be composed of official representatives from each participating AES or cooperating agency, with the Administrative Advisor and NIFA representative serving as non-voting, ex-officio members. Membership is open to all states and agencies with interest in N management, and participation by additional scientists and stakeholders is encouraged.

The committee will be guided by an Executive Committee consisting of a Chair, Secretary, and Member-at-Large, each serving in a three-year rotating leadership cycle. Each year, a new Member-at-Large is elected, advancing to Secretary in year two and Chair in year three. The Chair is responsible for setting agendas, presiding over meetings, preparing annual and mid-term reports, and ensuring project documentation is posted to NIMSS (www.nimss.org). The Secretary records and distributes official minutes and assumes the Chair’s duties when necessary. The Member-at-Large manages local meeting arrangements and supports the Executive Committee as needed.

The Technical Committee will hold an annual meeting and additional meetings as necessary. Subcommittees and working groups may be appointed by the Chair to address specific functions such as methods of harmonization, data synthesis, or outreach coordination. The Administrative Advisor will provide oversight and guidance, while the NIFA representative will ensure alignment with national priorities. This governance structure ensures continuity of leadership, accountability, and effective coordination across states.

Land Grant Participating States/Institutions: CA, DE, IA, IL, IN, KY, KS, MA, NE, MN, MI, MO, MS, NC, ND, OK, OH, SD, TN, UT, WI

 

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Attachments

Land Grant Participating States/Institutions

DE, IN, KY, MI, MN

Non Land Grant Participating States/Institutions