Growers in Alabama have to deal with frequent and prolonged wet periods which lead to untimely application. Common insects such as soybean loopers and velvetbean caterpillars are devastating to soybean crop, causing complete defoliation and yield loss in severe cases if insecticides are not sprayed before insect infestation. Untimely herbicide applications also created many weed control failures because wet field prevented growers spraying herbicides with their ground sprayers. Majority of the row crops fields in Alabama and the Southeast are relatively small compared to mid-south or Midwest. Many of them are irregular in shape, making ground sprayers and airplanes less efficient to spray them. In addition, large ground sprayers run over crops during late season pesticide application and desiccation and use over 20 gallons of fuel per hour. New spray drones have the potential to resolve these problems by applying pesticide aerially regardless field conditions. Spray drones will not damage crop foliage and can follow terrain change with downward terrain radars. They can spray odd shape fields, avoid obstacles automatically, save significant amount of time and diesel compared to large ground sprayers, and they require very little maintenance. Spray drone parts are very cheap compared to ground sprayers and do not require specialized training to replace parts. The latest spray drone models (Agras T50 and P100 Pro) can spray up to 50 acres of row crops per hour per drone at 2 GPA. Two operators flying two large drones can spray 80-100 acres per hour with a mixing trailer on relatively open fields. Spray drones can be folded and stored in mixing trailer or truck bed, so transporting them on highway is easy and safe compared to large farming equipment. Drones can also spread dry materials and cover crop seeds over crops before harvest. This will allow growers to divert their workload before harvest and get cover crop spreading done before the busy harvest season. Moreover, obtaining a federal license from FAA to fly these drones is getting easier and faster than before, allowing more people to become legal drone pilots to spray their crops.

The objectives of this study include:
1) compare deposition and canopy penetration of spray drone and ground sprayer at 3 and 15 GPA respectively
2) evaluate soybean desiccation efficacy and spray uniformity of spray drones compared to ground sprayers
3) assess Gramoxone alternatives in drone applications
4) spread common cover crop species on soybeans with drone before harvesting and evaluate stand establishment.

1. # of treatments completed
2. # of trials completed
3. # of new recommendations generated from this project
4. # of presentations made to promote project results and key findings
5. # of people reached by outreach efforts
6. # of students trained in this project

Updated August 25, 2025:
This project funded by National Soybean Checkoff is moving forward as planned. The main objectives listed below will be evaluated in field studies starting August of 2025.
1. Compare spray drone to ground sprayer in deposition and canopy penetration using different GPA and nozzles. (4 treatments to be conducted at 2 locations)
2. Evaluate how drift reducing agent/deposition aid affect spray deposition and canopy penetration in drone applications (4 treatments to be conducted at 2 locations)
3. Confirm if spraying soybean desiccant will affect common cover crop germination if seeds are spread before the application (5 cover crop species to be conducted at 2 locations)
4. Compare desiccation efficacy between spray drones and ground sprayers using 2-5 GPA vs 15 GPA (5 treatments to be conducted at two locations)
The project team has identified two soybean fields on farm in South Alabama for this project that can be seen below. Soybean stand and growth are very uniform in these two fields. Ground sprayer will be provided by the farmer to make all applications required in this project. Project team will use the newest large spray drone model (J100 or HD580) to make the applications. Fluorescent dye will be used to compare deposition and canopy penetration of spray drone and ground sprayer. Desiccation chemicals will include Gramoxone, Defol 5, Sharpen and Aim. All applications and data collection are expected to be completed by end of September except for cover crop establishment evaluation.

View uploaded report

Growers in Alabama have to deal with frequent and prolonged wet periods which lead to untimely application. Common insects such as soybean loopers and velvetbean caterpillars are devastating to soybean crop, causing complete defoliation and yield loss in severe cases if insecticides are not sprayed before insect infestation. Untimely herbicide applications also created many weed control failures because wet field prevented growers spraying herbicides with their ground sprayers. Majority of the row crops fields in Alabama and the Southeast are relatively small compared to midsouth or Midwest. Many of them are irregular in shape, making ground sprayers and airplanes less efficient to spray them. In addition, large ground sprayers run over crops during late season pesticide application and desiccation and use over 20 gallons of fuel per hour. New spray drones have the potential to resolve these problems by applying pesticide aerially regardless field conditions.