This proposal is for a second year of continued funding (FY24). The project from year one (FY23) is being implemented during the 2023 growing season.
Herbicides are the primary tool used for weed management in soybean (USDA – National Agricultural Statistics Service). Difficult to manage weeds (pigweed species, ragweed species, foxtail species, common lambsquarters, kochia, horseweeed, etc.) as well as herbicide-resistant populations for many of these weeds have been selected over time across North Central US soybean cropping systems. Increasing herbicide costs and environmental concerns have only added to management challenges. Current herbicide application practices focus on broadcast applications that deliver a constant herbicide rate across an entire field. However, weed populations have great spatial variability that is influenced by factors such as weed species biology, soil type, crop rotation, and tillage and harvest practices. Previous research has evaluated site-specific weed management (SSWM) using weed species distribution maps and site-specific herbicide applications resulting in herbicide savings ranging from 23 to 89% (Gerhards et al., 2022). Despite the potential economic and environmental benefits with SSWM, current technologies have not been able to achieve this on a field scale. With recent improvements and integration of active sensors and sprayer technologies, the ability to detect and treat weeds on a real-time site-specific basis should soon become feasible. Several companies are developing smart sprayers with the ability to detect and spray weeds in real-time both in fallow (green on brown) and early-season in crop (green on green). This technology has potential to shift from broadcast herbicide applications that deliver a constant herbicide rate across an entire field to only treating parts of the field where weeds occur. This could further improve herbicide efficacy as herbicide doses could be adjusted based on weed size and weed species as detection technology improves for species identification, potentially reducing overall herbicide cost and use. This system has potential to improve weed management in soybean using technology driven SSWM.
The long-term goal of this research project is to optimize herbicide applications with a smart sprayer system in the US to stimulate the adoption of precision agriculture tools for more sustainable weed management programs.
Our research team has the skills and research equipment related to weed management and pesticide application technology to successfully complete this project. The second year of the research project (FY24) will be conducted at the University of Wisconsin-Madison (Werle), University of Nebraska-Lincoln (Proctor), Kansas State University (Dille), and the BASF Midwest Research Farm near Seymour, IL (Miller/Werle). The project collaborators have a well-established partnership with BASF (Dr. Bruno Vieira, Kalvin Miller et al.) enabling access to a small plot (mobile 10-ft tractor mounted) and large-scale sprayers (60-ft boom, located in NE) equipped with the BASF-Bosch Smart Spraying Technology. These four research sites are located in strategic soybean producing regions of the United States. Moreover, these research sites are infested with the most common and troublesome weeds that North Central US soybean growers are facing (pigweed species, ragweed species, foxtail species, common lambsquarters, kochia, horseweed, etc.). While the BASF-Bosch Smart Spraying technology will be used, inferences from this project could be applied to other similar technologies such as the John Deere-Blue River and the Greeneye sprayer systems.
This project will evaluate different configurations of site-specific herbicide applications to control weed infestations in soybean using preemergence and postemergence herbicide programs. Studies will test the BASF-Bosch Smart Spraying Technology with large-scale (studies with >40 acres) field projects in NE and small plot projects in IL, KS and WI to evaluate weed detection, targeted spray deposition, weed control, end-of season weed seed production, reduction in herbicide usage for spot-spray compared to broadcast herbicide applications, nozzle selection (broadcast vs even nozzles), target area optimization (1 vs 3 nozzle spot spray area), and soybean yield.
Multiple years are planned to be able to follow weed community response to spot-spray applications under a soybean-corn rotation with each phase of the rotation planted and evaluated each year. Plots will be established, maintained, and evaluated for multiple years with same treatments applied to each plot through time. This proposal will support a second year of funding from NCSRP but would be year 3 of a multi-year study.
A range of treatments will be evaluated in small- and large-plot studies in 2023 and are proposed to repeat for a second year in 2024.
In 2023 Werle's lab will have 2 studies with the small plot smart sprayer at Seymour IL to evaluate herbicide program efficacy. In addition, 2 studies replicated at 2 locations in WI will evaluate the effects of weed control from different nozzle types (broadcast vs even) and spot spray areas (1 vs 3 nozzles). Another study in WI will evaluate spray coverage with different spot spray nozzles and boom height configurations.
Dr Dille’s lab at KSU will have two soybean studies in 2023, one is a repeat of a trial initiated in 2022 and one is a new study evaluating spot-spray programs with different rate structures. These trials will be conducted in KS and IL on both soybean and corn.
In 2023, Dr. Proctors lab will conduct a greenhouse trial evaluating the effect of different herbicide doses across a range of weed sized to simulate different spot spraying scenarios. They will also conduct a series of spray chamber trials evaluating spray patterns of different nozzle configurations that might be utilized on a spot sprayer. Finally, they will conduct field trials evaluating weed control using different broadcast and spot spray rates and chemistries to help develop soybean and corn herbicide program recommendations with spot sprayer technologies.
There is evidence of economic gains when optimizing herbicide weed control through increased weed control efficacy and reduced herbicide load (>70% reduction) in the field and environment using smart-sprayer technologies (Zanin et al., 2022; Ruigrok et al., 2020). Knowing that weed populations most often occur in patches throughout the field highlights the opportunity to target weed control to those locations. With the newer technologies including multiple booms and tanks, we can ensure that weeds are not missed by using broadcast applications from one boom while spot spraying when weeds are detected by the sensors. Through this research, we can explore and demonstrate how to optimize efficacy of troublesome weed species occurring in soybean fields across the North Central region.
In the future, optimizing the smart-sprayer technology with other integrated weed management approaches, such as using diverse crop rotations, including cover crops, changing row spacing and planting populations, and applying multiple effective herbicide sites of action together with sensor-based weed identification, we can demonstrate at the field scale the potential economic gains for soybean farmers.

Objectives: 1) Test preemergence and postemergence spot-spray herbicide program concepts in soybean and 2) evaluate and demonstrate the efficacy of the BASF Digital Farming GmbH (BASF) and Robert Bosch GmbH (Bosch) Smart Sprayer™

• Technical Extension bulletins produced for growers and decision influencers.
• Several young professionals will be trained on this novel technology while supporting the research; they will soon join the workforce and be an influencer for adopting such technology.
• Field day demonstrations for soybean growers – especially targeted for North Central soybean checkoff members.
• Social media posts highlighting in-season equipment demonstrations.
• Multiple refereed journal articles, conference presentations, and proceedings will be developed with the project findings.
• Conference papers will be presented at professional meetings (e.g., North Central Weed Science Society, Weed Science Society of America) to discuss the study methods and research findings.
• Manuscripts will be published in scientific journals (e.g., Pest Management Science, Weed Technology).

Update:
2024 NCSRP Progress Report
Planning for the 2024 growing season was conducted from October 2023 to April 2024.
During the 2024 growing season, Dr. Werle’s lab intend to replicate the experiments evaluating the role of nozzle type, number, and height for spot spray technologies. They also intend to replicate the experiments evaluating the impact of spot spray application time (different crop and weed stages) and modality (one tank versus two tank, with and without layered residual herbicides) on control of Amaranthus species in soybean. Novel experiments to be established in 2024 and replicated in 2025 will evaluate the role of chemical program selection and weed detection thresholds for weed control with spot spray technologies in soybean cropping systems. A graduate student (Zaim Ugljic) and a research scholar (TBD) will be 100% focused on these projects during the 2024 growing season. New in 2024, the team intends to take drone imagery from these research trials as part of their data collection process.
At Kansas State University, we wrapped up the soybean field trial conducted during 2023. Five different herbicide programs were evaluated using the BOSCH BASF Smart Sprayer technology. Results from the two years of experimentation (2022 and 2023) were summarized and prepared as part of a PhD dissertation chapter (Barnhart 2024). In general, the two-pass programs that include broadcast applications of soil-applied herbicide and targeted herbicide applications at both the burndown (green-on-brown) and in-crop postemergence (green-on-green) treatments provided consistent and excellent weed control in soybean. This was in contrast to one-pass programs with only targeted herbicide applications that did not provide season-long weed control benefits.
For 2024 experiments, the herbicide programs will be repeated on the same field site and plots as in 2022 (in a rotation sequence with corn) to evaluate the long-term impact of using smart sprayer technology on weed population dynamics in the field. Additional data to track the influence of programs on weed communities include spatial soil seedbank sampling and seedling emergence, drone imagery of populations across the field site, and end-of-season weed biomass and seed production.
At KSU, one PhD graduate student and one undergraduate research scholar worked on the field project during the summer of 2023. A new research scholar will start May 2024 to work on this field study and will transition to an MS student in Jan 2025 to continue the project in the future.

EXTENSION PRESENTATIONS
Crop Protection Netwok: See & Spray Technologies Webinar: https://www.youtube.com/watch?v=R3Dgx8fDp0w
Ohio State University Weed Scholar: See & Spray Precision Herbicide Applications Technologies Webinar: https://www.youtube.com/watch?v=LuEtcTxoVok&t=1s

INVITED PRESENTATIONS (CLASSROOM & SYMPOSIUM)
Barnhart IH, Kruger G, Miller K, Proctor C, Werle R, Dille JA (2023) Evaluating the One Smart Sprayer® in Midwestern United States corn and soybean cropping systems. Agronomy Departmental Seminar (AGRON 810), Kansas State University, Manhattan, KS (November 2023).
Barnhart IH (Presenter, PhD student), Dille JA (2023) Evaluating the One Smart Sprayer® Smart Sprayer ™ in Midwestern United States corn and soybean cropping systems. DA3: Digital Ag and Advanced Analytics Symposium, Manhattan, KS (October 2023)
Barnhart IH (2024) Use of artificial intelligence to locate and treat weeds in Midwestern United States corn (Zea mays) and soybean (Glycine max) cropping systems. PhD Dissertation, Kansas State University, Manhattan, KS (presentation, April 5, 2024)
Ugljic, Z., R.P. DeWerff, A. Dille, C. Proctor, K. Miller, R. Werle. 2023. See smart – spray smart! Quantifying the relationship between weed infestation and treated area with the ONE Smart Spray system and Xarvio’s Field Manager. University of Wisconsin-Madison, Department of Plant and Agroecosystem Sciences graduate student seminar.

PROFESSIONAL MEETING ABSTRACTS
Barnhart, I. (Presenter, PhD student), Miller, K., Kruger, G., Proctor, C., Vitti, T. H., Dille, A. (2023). Targeted Precision Weed Control Using the One Smart SprayerTM in Soybeans. North Central Weed Science Society Annual Meeting, Minneapolis, Minnesota (December 2023).
Krabbenborg, D. J. (Presenter, Undergrad student), Vitti, T. H., Proctor, C. (2023). Evaluating the Impact of Tank-mix Antagonism and Spray Nozzle Incompatibility with a Two-boom Two-tank Application System on Weed Control Efficacy. North Central Weed Science Society Annual Meeting, Minneapolis, Minnesota (December 2023).
Ugljic, Z., B. Canella Vieira, R.P. DeWerff, and R. Werle. 2024. Smart sprayer applications: Role of nozzle type, number, and height. Proceedings of the Weed Science Society of America Annual Meetings, San Antonio, TX.
Ugljic, Z., R.P. DeWerff, B. Canella Vieira, and R. Werle. 2023. More is less or less is more? Evaluating the influence of nozzle number and type for novel spot spray technologies. Proceedings of the North Central Weed Science Society Annual Meetings, Minneapolis, MN.
Ugljic, Z., R.P. DeWerff, N.J. Arneson, A. Dille, C. Proctor, K. Miller, R. Werle. 2023. See smart – spray smart! Quantifying the relationship between weed infestation and treated area with the ONE Smart Spray system and Xarvio’s Field Manager. Proceedings of the North Central Weed Science Society Annual Meetings, Minneapolis, MN.
Vitti, T.H. (Presenter, MS student), Canela Vieira, B., Kruger, G.R., Lawrence, N., Proctor, C. (2023). The effect of weed size and application rate on control of different herbicides and weed species. NCWSS Annual Meeting, Minneapolis, MN. (December 2023)

This project will:
-Evaluate new weed management smart sprayer technology that may improve control of hard to manage/resistant weeds, reduce herbicide use/cost
-Investigate smart sprayer technology to determine how it might most effectively be utilized for managing weeds in soybean
-Provide insight into the potential return on investment of new smart sprayer technology