Brief Summary of Minutes of Annual Meeting

The 2026 NC1195 annual meeting was held in hybrid format on February 19 to 20, 2026, with 9 participants attending in person in Kansas City, Missouri, and 11 participants joining virtually. The meeting opened with introductions, approval of the 2025 meeting minutes without revision, and review of the agenda. The committee also received administrative updates from Christina Hamilton (christina.hamilton@wisc.edu) on behalf of AAs Troy Runge and Derek McLean regarding the renewal process, annual reporting expectations, and the transition to the new project ID. The group welcomed new investigators (Crystal Lu and Anna Cates) and administrative advisors (Troy Runge (trunge@wisc.edu) – University of Wisconsin-Madison and Derek McLean (derek.mclean@unl.edu) – University of Nebraska-Lincoln, and recognized that the renewal proposal had been submitted in October 2025 and remained under review.

State reports and research updates occupied most of the meeting and reflected the broad multistate scope of NC1195. Presentations covered nitrogen response to winter cover crops, nitrogen rate optimization, soil health testing, compost and manure nitrogen cycling, prairie systems, process based and machine learning models of nitrous oxide emissions, enhanced efficiency fertilizers, precision nitrogen management using crop sensors and imagery, watershed scale nitrogen loss, and regional benchmarking efforts such as the Iowa Nitrogen Initiative. Across these presentations, a common theme emerged that nitrogen recommendations must better account for site specific conditions, including cover crop identity, weather, soil properties, manure type, irrigation system, and spatial variability within fields. 

The meeting also generated strong momentum around collaboration. Members discussed the value of coordinated analyses using existing nitrogen rate datasets across states, especially datasets containing zero nitrogen controls, mineralization measurements, and in season nitrogen information. Participants from several states volunteered data, soil analyses, and curation support for a shared nitrogen response database, and the incoming chair was tasked with coordinating a template, follow up discussions, and a mini proposal to support this effort. The group agreed that future multistate products should include shared databases, decision tools, and publications that make better use of historical and ongoing regional trial data.

For committee business, the group agreed to hold the 2027 meeting on February 25 to 26, 2027, in Kansas City, Missouri. Leadership changes were also confirmed: Peter Tomlinson moved to Member at Large, Xia Zhu-Barker became Chair, and John Jones became Secretary. These decisions, together with the renewal activities and new collaborative data effort, positioned the committee for continued multistate coordination in the next reporting period. 

State report presentation and discussion

• State reports. Nine in-person and seven virtual attendees gave 20-35 minutes presentations about their work relevant to the overall project theme, followed by a discussion of each topic area:
• Xia Zhu-Barker (University of Wisconsin-Madison): Enhancing N utilization through mechanistic insights into fertilizer-manure-soil interactions
• Peter Tomlinson (Kansas State University): Flickner Innovation Farm: Paired watersheds 
• Javed Iqubal (University of Nebraska-Lincoln): From prediction to precision: Nitrogen tools to improve NUE and water quality in Nebraska
• Debasish Saha (University of Tennessee): Enhanced prediction of soil nitrous oxide emissions using machine learning augmented with agroecosystem model 
• Will Horwath (University of California Davis): Biogeochemical and soil health response of surficial application of dairy manure compost in almond orchard soils
• John Jones (University of Illinois Urbana-Champaign): Corn nitrogen research, outreach, and fertilizer recommendation updates
• Jeanette Norton (Utah State University): Relationships between soil carbon and nitrogen health indicators in a silage corn system with contrasting nitrogen sources 
• Michael Castellano (Iowa State University): The Iowa nitrogen initiative
• Ali Nafchi (South Dakoda State University): Smarter nitrogen fertilization with crops as biosensors 
• Alex Woodley (NC State University): Use of EEFS in corn productions in NC – Yields and N loss evaluation
• Crystal Lu (University of Wisconsin-Madison): Targeting agricultural management practices to reduce nitrogen loading
• Natasha Rayne (University of Wisconsin-Madison): Modernizing nutrient management guidelines for Wisconsin: Re-evaluating manure derived nitrogen
• Anna Cates (University of Minnesota): Minnesota office for soil health
• Hannah Poffenbarger (University of Kentucky): Uncertainty Regarding nitrogen management following cover crops
• Andy Vanlookcke (Iowa State University): How much do cover crops and prairie reduce N losses?
• Whoi Cho (South Dakota State University): Potassium carryover

• Key discussions: 

• Collaborative use of the existing regional data to develop decision tools and publications
• Meeting in 2027: The group agreed to hold the next meeting on February 25-26, 2027, at Fairfield Inn and Suites, Kansas City, MO. (Motion: Peter Tomlinson; Second: Xia Zhu-Barker; Motion Approved)
• Executive Committee Changes: The current Chair, Peter Tomlinson, will be the Member-at-Large since February 2026; the current Secretary, Xia Zhu-Barker will be the Chair since February 2026. John Jones will be the Secretary since February 2026.

Accomplishments summaries by major objectives of the project:

1. Determine the roles of innovative management practices, the environment, and their interactions on the optimum use of nitrogen in agroecosystems.

•  Multistate research showed that nitrogen recommendations depend strongly on management context and environmental conditions. Cover crop studies spanning multiple locations found that corn following cereal rye often required more fertilizer nitrogen than corn following fallow, while legume cover crops generally lowered nitrogen requirements and mixtures were intermediate. These results reinforce that cover crop effects on nitrogen management cannot be generalized without considering cover crop identity and related residue characteristics such as carbon to nitrogen ratio. 
• Research from Illinois, Nebraska, Kansas, North Carolina, and South Dakota further showed that nitrogen rate, timing, source, and placement interact with weather, soil properties, irrigation system, and within field variability. Presentations on enhanced efficiency fertilizers, sensor-based recommendations, fertigation, precision yield mapping, and benchmarking efforts all pointed to the same conclusion: fixed nitrogen plans are often less effective than approaches that respond to field and seasonal conditions. Collectively, these studies advanced the project objective by identifying where innovative nitrogen strategies are most likely to improve efficiency, maintain yield, and reduce unnecessary fertilizer use.

 2. Understand the role of soil biological processes in controlling plant available nitrogen and their relationships with soil health and system resilience.

•  Prairie, manure, compost, and soil health studies across states improved understanding of the biological controls on plant available nitrogen and nitrogen losses. Prairie systems lowered nitrate leaching, cover crops reduced nitrate loss, and manure processing strongly changed mineralization and ammonia loss patterns.
• California orchard work showed that compost reduced nitrous oxide emissions and is now being paired with isotopomer, microbial, and carbon use efficiency analyses to identify whether nitrification or denitrification pathways are being altered.
• Soil health test evaluations in Minnesota and related committee discussions showed that common tests such as Haney style metrics are not yet reliable stand alone predictors of economic optimum nitrogen rate, highlighting the need for better biology based indicators tied to mineralization, respiration, soil structure, and resilience.

3. Translate field and laboratory research into nitrogen management decision-making tools and educational resources promoting improved profitability and sustainability of corn-based cropping systems.

• Process augmented machine learning models improved prediction of soil nitrous oxide emissions and demonstrated the value of combining field observations with process based simulations for future decision support tools.
• Sensor based and imagery based nitrogen management platforms in Nebraska and South Dakota showed that reactive in season management can improve nitrogen use efficiency and profitability compared with static recommendations, especially when paired with split application or fertigation.
• The committee agreed to begin building a shared regional database of nitrogen response trials and related metadata. This effort will support future publications, extension products, and data driven recommendation tools relevant to corn based cropping systems across the North Central region and beyond.

1. Cassman, K.G., Poffenbarger, H., Baum, M., Canisares, L.P., Puntel, L.A., Merlos, F.A., Grove, J.H., Castellano, M., 2025. The missing link: A purpose‐led framework for assessing soil health. Soil Sci Soc Am J 89, e70144.
2. Curtright, A.J., Smith, C., Horwath, W.R., Zhu-Barker, X., 2026b. Mineral associated organic matter fractions have an outsized role in nitrogen mineralization and denitrification. Geoderma 468, 117758.
3. Mirabella, J.P., von Haden, A., Sanford, G., Ruark, M., Zhu-Barker, X., 2025. Fate of synthetic fertilizer nitrogen in a maize system depends on dairy manure type: insights from an isotopic tracing field study. Biol Fert Soils, 1-17.
4. Nelson, J. T., Dor, M., VanLoocke, A. D., Studt, J. E., Schrock, P. K., & McDaniel, M. (2025). Miscanthus× giganteus increases soil maximum water holding capacity compared to maize. Agrosystems, Geosciences & Environment, 8(3), e70181.
5. Yi, B., Huang, W., Liebman, M., Woods, M., McDaniel, M. D., Lu, C., ... VanLoocke, A. D.& Hall, S. J. (2025). Diversified cropping systems with limited carbon accrual but increased nitrogen supply. Nature Sustainability, 8(2), 152-161.
6. Ordóñez, R. A., White, C. M., Spargo, J. T., Kaye, J. P., Ruark, M., Iqbal, J., Shapiro, C. A., Thomason, W. E., Fiorellino, N. M., Thorne, L. A., Shober, A., Grove, J. H., Hirsh, S. M., Weil, R. R., Castellano, M. J., Archontoulis, S. V., Hatfield, J. J., Lee, C. D., Quinn, D. J., … Vyn, T. J. (2025). Delta yield predicts nitrogen fertilizer requirements for corn in US production systems. Agronomy Journal, 117, e70150. https://doi.org/10.1002/agj2.70150
7. Yi, B., Huang, W., Liebman, , McDaniel, M., Lu, C., VanLoocke, A.,.. Poffenbarger, H, et al.Diversified cropping systems with limited carbon accrual but increased nitrogen supply. Nat Sustain 8, 152–161 (2025). https://doi.org/10.1038/s41893-024-01495-4
8. Dhaliwal, J. K., Lussich, F., Jagadamma, S., Smith, A., & Saha, D. (2025). Long-term cover cropping and nitrogen fertilization impacts on net global warming potential of continuous no-till cotton cropping system. Journal of Environmental Quality, 54(5), 934–946. https://doi.org/10.1002/jeq2.70046
9. Ballagh, B., Ballagh, A., Bushong, J., & Arnall, D. B. (2025). The Effect of Nitrogen Fertilizer Placement and Timing on Winter Wheat Grain Yield and Protein Concentration. Agronomy, 15(8), 1890. https://doi.org/10.3390/agronomy15081890
10. Sharry, R., Arnall, D. B., Phillips, S., & Souza, J. B. (2025). Recovery of Beef Cattle Manure Nitrogen in a Long-Term Winter Wheat Fertility Study. Nitrogen, 6(2), 28. https://doi.org/10.3390/nitrogen6020028
11. Abiola, S. O., Sharry, R., Bushong, J., & Arnall, D. B. (2025). Optimizing Spray Technology and Nitrogen Sources for Wheat Grain Protein Enhancement. Agriculture, 15(8), 812. https://doi.org/10.3390/agriculture15080812
12. Huddell, A. M., Davis, B., Richards, N., Tully, K., Thapa, R., Hashemi, M., VanGessel, M., Miller, J., Ketterings, Q. M., White, C., Roth, G., Spargo, J. T., & Mirsky, S. B. (2025). Nitrogen fertilizer rate not timing determines no-till corn yield following cereal rye cover crop in northeastern United States. Agricultural & Environmental Letters, 10, e70041. https://doi.org/10.1002/ael2.70041
13. Zhang, C., Li, X., Mieno, T., Diao, C., and Bullock, D. S., 2025. Quadratic-plateau geographically weighted regression model for estimating site-specific economically optimal input rates. Comput Electron Agric, 237(Part B), 110655.