Research HighlightsSmart Spray Technology for Weed Management Gets a Closer Look
In this article, you’ll find details on:
- Midwestern researchers are testing smart sprayers to help farmers with optimizing herbicide use and weed control.
- Through a project with North Central Soybean Research Program, the researchers are comparing herbicide programs and timing using a smart sprayer vs. a broadcast application for effectiveness.
- Nozzle type, number of nozzles and boom height play important roles in the effectiveness of smart spray technology weed control.
By Carol Brown
Smart spray technology for post-emergence weed management is fairly new to U.S. agriculture. Equipment manufacturers have developed camera-based technology that can identify weeds and direct herbicide application accurately. The cameras can be retrofitted to a standard sprayer or a sprayer can be purchased with built-in camera technology.
A team of Midwestern researchers are hoping to shed some light on the accuracy and effectiveness of this technology through a multi-year project supported by the North Central Soybean Research Program (NCSRP).
“Smart spray technology to target weed termination has been commercially available in the U.S. for about five years,” says Chris Proctor, University of Nebraska weed management extension educator and principal investigator for the project. “We are trying to fine-tune these smart spray programs for post-emergence herbicides by looking at different application rates and sprayer configurations for successful weed control.”
The team is conducting small-plot trials in Kansas, Wisconsin and Illinois, and on a larger scale in Nebraska. They are finishing their third crop year of data gathering for the project.
Anita Dille, a weed ecology professor at Kansas State University, and her team are looking at broad system herbicide management plans and scenarios that integrate smart spray technology. She has been tracking this over the course of the project to see how effective these systems are and to monitor any shifts in the weed community over time.
Proctor, along with Rodrigo Werle’s team in Wisconsin, are conducting comparisons between herbicide programs, application approaches and timing. Werle is an extension cropping systems weed scientist at the University of Wisconsin-Madison. Werle’s graduate student, Zaim Ugljic, is leading the work for this project.
“The variables between different sprayers — whether they have had a camera added or have one built-in — while important, it comes down to nozzles: which types and how many are activated upon weed detection,” Ugljic says. “In our trials, we used two nozzle types and two boom heights to evaluate weed control differences between broadcast and spot spraying.”
The team evaluated a tank mix of Liberty and Roundup PowerMAX, both with and without the inclusion of Outlook, a residual herbicide. These combinations were tested as broadcast and spot spray applications. Additionally, a dual tank treatment was assessed, where Liberty and Roundup were spot sprayed with a smart boom, while Outlook was broadcast-applied using a standard boom. They applied herbicides at V2 and V4 soybean growth stages. The hypothesis was that early applications would reduce the area treated with foliar herbicides and that weed control efficacy with spot spraying would be comparable to a broadcast application.
“We found that with early application for both broadcast and spot spray, there was 90% control of weeds, and the addition of a residual herbicide was important,” Ugljic explains. “At the later application time, more weeds had emerged and the smart sprayer basically acted more like a broadcast sprayer because it was constantly spraying. In the early application, the residual herbicides did the heavy lifting, no matter which type of sprayer was used. At late application, the residual herbicide didn’t make a big difference. But we should be careful, because this is an option if – and only if — your post program works, which will continue to put selection pressure on foliar chemistry.”
When measuring how much product the two post application timings used, Ugljic saw a 76% savings of foliar herbicides at early application with the smart sprayer, but only a 26% savings with the late application in 2023. The team is in the process of analyzing data from this year’s plots to see if results will be similar to the previous year’s results.
Research Roots in Nebraska
Proctor and his team started looking at spot sprayer technology a few years ago prior to the NCSRP project. They’ve been working in the lab and greenhouse to understand weed size detection by the smart sprayer and herbicide dosage amounts. They have also explored different nozzle configurations and numbers of nozzles activated to target the weed identified by the smart sprayer camera.
He has also been looking at spot spraying with residual and non-residual herbicides at the field scale and coming to similar conclusions as Ugljic in Wisconsin. The project uses a pre-emergence application and they are focusing on weeds that have come through that first round of herbicide.
“Without the residual herbicide, the benefit of spot-spray technology is mostly lost because with too many weeds coming up in the field, the sprayer reverts to a broadcast application,” Proctor says. “The residual herbicide suppresses a lot of weeds, and we can use the spot sprayer to target those that break through. This targeted approach seems to be the best fit that we’ve seen for the spot-spray technology.”
Nozzle configuration and boom height are important pieces of the puzzle. A smaller spray area enables a more direct target, but opens the potential for misses and skips, Proctor says, but multiple nozzles can compensate for changes in boom height to achieve success. Ugljic is exploring how different nozzle types, as well as boom height and stability, can affect herbicide application coverage and weed control efficacy with smart sprayer applications.
After these years of processing research data, Proctor and the team see the value in smart spray technology, but caution farmers who adopt the technology.
“Farmers shouldn’t buy a smart sprayer and continue to use their same weed management approach,” Proctor comments. “This system functions differently, so farmers need to create a specialized process around it.”
Proctor and the team appreciate that NCSRP could help expand this work to advance the research. They’ve been able to support students on the project and expand their outreach about this technology through a YouTube webinar.
Additional Resources
Spot Spray Technology webinar from the University of Wisconsin – YouTube webinar
Three things to Know About Spot Spray Technology Today – GROW article
Herbicide Savings from Precision Spraying Technology – GROW article
Published: Jan 6, 2025
The materials on SRIN were funded with checkoff dollars from United Soybean Board and the North Central Soybean Research Program. To find checkoff funded research related to this research highlight or to see other checkoff research projects, please visit the National Soybean Checkoff Research Database.
