Brief Summary of Minutes of Annual Meeting

• Welcome, introductions, agenda review: the meeting started with a general welcome to the group and reviewing the agenda. Introductions were done with the whole group. About 40% of the 16 committee members virtually attended the meeting.
• State report highlights: All attendees gave 20-35 minutes presentations about their work relevant to this project theme, followed by a discussion of each topic area.
  • Will Horwath (University of California Davis): Compost effects on C and N cycling dynamics in California Tomato cropping systems
  • Matthew Ruark (University of Wisconsin-Madison): Cover crop biomass and soil nitrate by rye seeding rate; nitrogen fertilizer rate on corn yields; shoot: root biomass of rye biomass by rye seeding rate
  • Marshall McDaniel (Iowa State University): Are labile C and N like Las Vegas – What happens in the surface stays in the surface?
  • Peter Tomilson (Kansas State University): Legacy effects of cover crops on N availability in the cropping system and yield response to N fertilization; Flickner Innovation Farm: Paired watershed
  • Daniel J. Quinn (Purdue University): N fertilizer Research; Impact of in-season N fertilizer timing in cover crop systems
  • Sami Khanal (Ohio State University): Simulated effects of management practices on greenhouse gas emissions and soil organic carbon in the Maumee River Watershed
  • Debasish Saha (University of Tennessee): Nitrous oxide emissions from long-term soil health practices
  • Xiaofei Li (Mississippi State University): Economic performance of MRTN using on-farm precision experimentation data
  • Rhae Drijber (University of Nebraska-Lincoln): Harnessing soil biology for improved crop production
  • Ali M. Nafchi (South Dakota State University): Using next-generation of precision ag applications to enhance nitrogen use efficiency
  • Mike Castellano (Iowa State University): Initiative to expand MRTN recommendation to account for genetic, environmental, and management factors that affect the dynamic nature of optimal N rates.
  • Brian Arnall (Oklahoma State University): Precision nutrient management in corn-cotton rotation production system
  • Fabian Fernandez (University of Minnesota): Mitigating nitrate, nitrous oxide, and ammonia loss in corn with a nitrogen source and application timing
  • Hanna Poffenbarger (University of Kentucky): How do cereal rye and legume cover crops affect corn's optimum N fertilizer rate?
• Administrative Update: John Erickson provided an administrative update on NIFA staffing/hiring status, as well as changes & reorganization to the AFRI program priority areas.
• Meeting in 2024: The group agreed to hold the next meeting on February 28-29, 2024, at Fairfield Inn and Suites, Kansas City, MO.
• Executive committee changes: The current Secretary, Sami Khanal, will be the Chair in 2024; the current Member-at-Large, Debasish Saha will be the Secretary. Peter Tomlinson was elected as the Member-at-Large for 2024. The current Chair, Hanna Poffenbarger, will be the past Chair.

Impact Nugget: A concise statement of MULTISTATE advancements, accomplishments, and impacts. 

• Advancements

This research project has resulted in an improved understanding of how various management practices influence nutrient and crop health dynamics, providing valuable guidance to farmers. Several works from the individual state members are in progress to develop more operation-specific recommendations, guidelines, and tools for nitrogen management.

• Accomplishments

Through numerous research trials conducted across various states by NC1195 members, this research project has demonstrated the role of various nitrogen management practices, such as in-season nitrogen (N) fertilizer management, cover crops, polymer-coated urea (PCU), compost, and long-term soil health practices, on lowering carbon and nitrogen footprint of agriculture while improving crop yields.

• Impacts

The NC1195 multistate group is developing guidelines and recommendations as to when farmers and consultants can use alternative N management practices (e.g., pre-plant PCU, cover crops, composts, and manure) to enhance N use efficiency (NUE), which are key to developing sustainable and regenerative agriculture in the U.S.

New Facilities and Equipment. Include production areas, sensors, instruments, and control systems purchased/installed, especially if these facilities and equipment are shared between states or facilitate multistate research.

• Poffenbarger, Ruark, Woodley, and Tomlinson are using the same NDVI-based vegetation sensor in a coordinated project to establish sensing methods to predict cover crop biomass.
• McDaniel and colleagues have started measuring soil nitrous oxide emissions via surveys using LI-7820 (LiCor, Lincoln, NE).

 Unique Project-Related Findings. 

• Several years of research that doing a single pre-plant application of polymer-coated urea (PCU) compared to a traditional fertilizer (urea) results in:
  • Reduction in N loss (nitrate leaching, and ammonia and nitrous oxide emissions to the atmosphere) by approximately 48%.
  • An agronomic benefit with greater grain production that compensated for the additional cost of PCU over urea. Calculated with typical prices during the study ($3.50 per bushel of corn and $0.35 per pound of nitrogen as urea and $0.55 per pound of nitrogen as PCU) the PCU application resulted in a net economic return of $4 per acre higher than when using urea.
• Long-term cropping systems experiment, including small grain and manure, has a greater proportion of N in less-likely-to-leach forms of N (i.e., salt-extractable organic and microbial biomass N).
  • This long-term experiment compares corn-soybean rotation with all synthetic N fertilizers (2-year) with corn-soybean-oat/alfalfa-alfalfa with >90% of N from composted cattle manure (4-year). There are 50 lbs of N per acre in microbial biomass N in the 4-year rotation compared to 2-year to 12” depth. This corresponds to less fertilizer N inputs and less nitrate leaching to groundwater (measured via suction cup lysimeters at 1.2 m deep).
• Field studies used to evaluate how forage crops such as silage corn or sorghum respond to alternative sources of N in wastes such as composts in California dairy forage systems indicated that compost had significant effects on crop yield, especially when in combination with reduced synthetic fertilizer inputs.
  • Yield results are in agreement with previous studies that found increased yields following food waste compost application in grain, perennial grass, microalgae, carrot, and tomato, following green waste compost application in corn.
  • Positive compost effects on yields appeared only after year 2 and show that multiple years of annual compost application may be necessary for yield benefits to justify its use.

 Accomplishment 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.

• The study involving 24 site-year field trials has shown that legume and mixture cover crops do not have a significant effect on the optimum N rate of corn, but cereal rye increases the optimum N rate of corn.
• Artificial subsurface drainage was found to increase the N use efficiency of corn, as well as the predictability of the optimum N rate of corn.
• Split application of N fertilizer was more efficient than pre-plant N application and provided advantages when corn followed a rye cover crop because of lower plant-available N supply in this system.

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

• NC 1195 committee members reviewed and synthesized literature to determine how plant breeding has affected crop residue inputs to the soil and soil organic matter, which is an important source of plant-available N in cropping systems.
• This project committee members have contributed to determining the best methods for aggregate stability and soil carbon indicators of soil health in a study involving long-term research sites in North America.
• This project committee members comprehensively estimated the effect of various N rates on 1) corn grain yield, 2) economic return, 3) nitrogen use efficiency of corn, 4) nitrate leaching load in tile-drained fields, 5) nitrous oxide emissions, and 6) ammonia volatilization.
• Field studies involving forage crops such as silage corn or sorghum to understand how these crops respond to N inputs in California dairy forage systems have shown that multiple years of compost application improves crop yield even without applying any synthetic fertilizer N inputs.
• This project committee members published 1) a peer-reviewed article on management impacts on soils, including soil biology, and the ability of soils to retain crop residues, and 2) a peer-reviewed review article relating to soil health and N sources for plants.

 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.

• The NC1195 research team quantified the profitability of variable-rate application of nitrogen fertilizer in corn production using on-farm experimental data.
• This research group has worked with a detailed process-based biogeochemical model, DeNitriification-DeComposition (DNDC), to understand the role of management practices on GHG emissions, soil carbon, and crop yields.
• The committee members are actively disseminating the findings from their research activities with farmers, consultants, and the broader agricultural community.

Published Written Works. 

  Note: Authors in bold texts indicate the NC1195 committee members

• Poffenbarger, H., Castellano, D. Egli, A. Jaconi, and V. Moore. 2023. Contributions of Plant Breeding to Soil Carbon Storage: Retrospect and Prospects. Crop Science, in press.
• Quinn, D., Poffenbarger, F. Miguez, and C. Lee. 2023. Corn Optimum Nitrogen Fertilizer Rate and Application Timing when Following a Rye Cover Crop. Field Crops Research 291: 108794. https://doi.org/10.1016/j.fcr.2022.108794
• Rieke, E.L. et al., including D. McDaniel, and H. Poffenbarger. 2022. Evaluation of Aggregate Stability Methods for Soil Health. Geoderma 428: 116156. https://doi.org/10.1016/j.geoderma.2022.116156
• Maas, E., S. Archontoulis, M. Helmers, J. Iqbal, C.H. Pederson, Poffenbarger, K.J. Tebockhorst, and M. Castellano. 2022. Subsurface Drainage Reduces the Amount and Interannual Variability of Optimum Nitrogen Fertilizer Input to Maize Cropping Systems in Southeast Iowa, USA. Field Crops Research 288: 108663. https://doi.org/10.1016/j.fcr.2022.108663
• Quinn, D., Poffenbarger, and C. Lee. 2022. Rye Cover Crop and In-Furrow Fertilizer and Fungicide Impacts on Corn Optimum Seeding Rate and Grain Yield. European Journal of Agronomy 139: 126529. https://doi.org/10.1016/j.eja.2022.126529
• Liptzin, De, et al., including D. McDaniel, and H. Poffenbarger. 2022. An Evaluation of Carbon Indicators on Soil Health in Long-Term Agricultural Experiments. Soil Biology and Biochemistry 172: 108708. https://doi.org/10.1016/j.soilbio.2022.108708
• Rieke, E.L., et al., including D. McDaniel and H. Poffenbarger. 2022. Linking Soil Microbial Community Structure to Potential Carbon Mineralization: A Continental Scale Assessment of Reduced Tillage. Soil Biology and Biochemistry 168: 108618. https://doi.org/10.1016/j.soilbio.2022.108618.
• Bagnall, D.K et al., including D. McDaniel, and H. Poffenbarger. 2022 Carbon-Sensitive Pedotransfer Functions for Plant-Available Water. Soil Science Society of America Journal 86: 612-629. https://doi.org/10.1002/saj2.20395
• Bagnall, D.K et al., including D. McDaniel and H. Poffenbarger. 2022 Selecting Soil Hydraulic Properties as Indicators of Soil Health: Measurement Response to Management and Site Characteristics. Soil Science Society of America Journal 86: 1206-1226. https://doi.org/10.1002/saj2.20428
• Spargo, J. T., et al., including Arnall and F.G. Fernández. 2022. A survey to evaluate the current status of land grant university and state department of agriculture soil fertility recommendations and analytical methods. Ag. Data Commons. https://doi.org/10.15482/USDA.ADC/1526506

Scientific and Outreach Oral Presentations.

• Canisares, L.P et al., including J Tomlinson, M. D Ruark, and H. Poffenbarger. 2022. Legume cover crops can reduce the corn reliance on nitrogen fertilizer when compared to cereal rye across multi-state field experiments. ASA-CSSA-SSSA meeting, Baltimore, MD.
• Antonio-Ordoņez, R., et al., including D Ruark, M.J. Castellano, H. Poffenbarger. 2022 Yield gap as a key metric to determining N fertilizer rates in maize crop. ASA-CSSA-SSSA meeting, Baltimore, MD.