Aerial Application Technology Research Session

NAAA Ag Aviation Expo
December 5–8, 2022 ♦ Knoxville, TN 
NAAA’s educational programming leads off with the Aerial Application Technology Research Session, led by aerial application researchers, possibly one of the convention’s most substantive sessions. This year’s session will cover several “new” tools and information ready to use as part of your everyday operations. Researchers have been working on most of these projects over the past several years and are eager to help make your applications more efficacious, make you an even better environmental steward and your application business more cutting-edge. Several states offer CEU credits for this session; be sure to sign in at the entranceway. 

2022 Aerial Application Technology Research Presentations

Title: Straight Stream Nozzle Models to Support Aerial Applications
Authors: Brad Fritz

Maintaining operational efficiency while mitigating spray drift potential can be challenging, particularly with modern aircraft that are capable of higher airspeeds.  One of the easiest and most effective tools for reducing off-target movement is increasing droplet size, which minimizes the fraction of spray volume containing smaller, drift prone droplets.  Proper nozzle selection and use is the first, and most significant step towards improving overall spray characteristics.  Models that guide nozzle selection and use are available for the most used widely used aerial application nozzles.  However, straight stream nozzles designed for ground boom banded spray applications were recently tested and used by aerial applicators and similar models were requested.  To support the increasing interest and use of these nozzles, and to provide the spray performance data needed to adhere with agrochemical product labels, new droplet size models were developed.  Two straight stream nozzle types were tested in a laboratory high speed wind tunnel using laser diffraction to measure droplet size. Models were developed that cover all orifice sizes, spray pressures from 30 to 90 psi, and airspeeds from 120 to 180 mph.  Overall performance and droplet size trends across the entire operational space are presented and discussed.  These models allow users to identify nozzle sizes and spray pressures that will deliver specified droplet sizes and classifications at any desired operational airspeed. 

Bio: Dr. Brad Fritz is an agricultural engineer and serves as the Research Leader of the USDA ARS Aerial Application Technology group in College Station, Texas.  His areas of research include spray drift measurement and mitigation, spray atomization, and optimization of application technologies and methods to enhance on target deposition while mitigating off target impact.  He is currently an active member of a number of professional organizations including the American Society of Agricultural and Biological Engineers, ASTM E35, the American Mosquito Control Association, and the National Agricultural Aviation Association.  
Title: Beyond strings and spray cards: progress in the continued development of a continuous swath measurement method and a scalable, automated strip scanning data acquisition device.
Authors: Mark Ledebuhr, Nick Tipper, Adam Brohl and Sarah Ziehm, Application Insight, LLC.

Commonly known and modelled variables that impact a spray quality are droplet size distribution (DSD), spray release height, wind, and travel speed. RPAAS also have additional variables of downward air energy, aircraft pitch and roll affecting the attitude of the spray nozzles, and potentially the impact of spraying operationally in forward and reverse. This very high number of variables makes predicting the quality and placement of an RPAAS spray more complicated than existing ground and aerial application methods. Systematic sampling with small cards and string samplers may risk missing very real deficiencies in these applications or may fail to identify poor uniformity use cases that should be avoided altogether. The need for an accurate, precise and fast swathing method that can make onsite, in-situ, near real-time spray evaluations for a given use case, is real and necessary. This talk details our progress in developing and refining a paper tape data collection method that is useful as a stand-alone method in and of itself, and a corresponding scalable strip scanner that allows for fast, highly precise quantification of the spray deposition captured on the tapes. The results can not only show swath quality, but also definitively show swath offset if present and the potential risk of nearfield off-swath drift. The goal of this project is to provide a method and a mechanism for near real-time swath evaluation so that UAS operators can make in-situ evaluations and adjustments, then immediately spray with confidence. This method will ultimately allow registrants and regulators to economically collect the large amount of new data required over the wide array of new use cases encountered with RPAAS to support risk assessments and establish sound operational limits for labels. 

Bio: Mark Ledebuhr is the managing partner of Application Insight, LLC.  Application Insight focuses on developing and optimizing spray application systems, in specialty and commodity crops, developing and improving methods for evaluation of spray application. Mr. Ledebuhr works collaboratively with hardware and chemical manufacturers, universities, state and federal government agencies, and private growers worldwide. He is a member of American Society of Agricultural and Biological Engineers (ASABE) Application Systems Committee PM23/6, American Society of Testing and Materials (ASTM) Committees E35 and E29, American Society of Pesticide Safety Educators (AAPSE), National Association of Independent Crop Consultants.(NAICC) and a member of the US delegation to International Standards Organization (ISO) Subcommittee TC23/SC6 (Application Systems). Current active research projects include: optimization of aerial application nozzles and high-pressure delivery systems, improvement of spray educational tools, development of high-resolution, high speed swath analysis methodologies, adaptation of ultra-low volume (ULV) technologies for vector control in drones, Solid Set Canopy Deposition Systems (SSCDS) for orchard spraying, and novel methods of drift detection technology. Ledebuhr is the co-author of the recently released book Airblast 101, recognized as the definitive text on the use and optimization of airblast and air-assisted spraying technologies. 
Title: Using freely available satellite imagery and software for creating crop growth and prescription maps
Authors: Chenghai Yang

The rapid increase in remote sensing data sources today presents both opportunities and challenges to remote sensing practitioners and end users. Remote sensing data are generally obtained using three major types of platforms: satellites, manned aircraft, and unmanned aircraft systems (UAS). UAS will be appropriate if imagery is needed for a small area or at very high spatial resolution. Manned aircraft or satellites will be more effective for imaging at farm or regional level. Although image users are aware of the availability of different image data sources, many of them are not clear what type of imagery to select, how to obtain it, and how to convert it to useful map products. This presentation will demonstrate practical procedures on how to use Sentinel-2 satellite imagery and the QGIS software, both of which are freely available to end users, to create useable vegetation maps for crop growth assessment and prescription maps for site-specific chemical application. Specifically, step-by-step procedures will be presented on how to download Sentinel-2 images and the QGIS software and how to view and process the images using QGIS. As an example, a Sentinel-2 image from a cropping area will be used to create both a normal color and a color-infrared image composite for image visualization, and a normalized difference vegetation index (NDVI) map for crop growth and health assessment. Furthermore, the NDVI image for a field will be classified into multiple zones to differentiate within-field plant growth variability that can be used for site-specific chemical application.

Bio: Dr. Chenghai Yang is a Research Agricultural Engineer with the USDA-ARS Aerial Application Technology Research Unit in College Station, TX. Dr. Yang’s research focuses on the development and application of remote sensing technologies for precision agriculture and pest management. His recent efforts have focused on developing low-cost imaging systems and image processing techniques and evaluating these systems with satellite imagery for assessing crop conditions for site-specific chemical applications. Dr. Yang has authored or co-authored over 160 peer-reviewed journal articles and serves on several national and international professional societies.
Title: Newer Pattern Testing Collection Equipment
Authors: Randy Price

A newer GoPro based pattern testing system was developed to analyze pattern test strings from aerial aircraft using standard parts and components from a local hardware store. The system uses a GoPro camera, green laser, and rhodamine filter to analyze the test strings, a cordless drill and measuring wheel to move the string through the device, and two 90-degree drill driver attachments and a paint roller to collect the strings. Advantages of the system are that it can be used over a larger set of environmental conditions, can collect test strings in 10 to 35 seconds, and requires fewer people to operate on the flight-line. 

Bio: Dr. Price is an Associate Professor at the LSU AgCenter, Baton Rouge, Louisiana.  He continually works on new equipment and methods to help the agricultural spray plane industry and is a certified Operation S.A.F.E. analyst.
Title: Card Based Spray Pattern Testing System Designed for Aerial Applicators to Use
Authors: Matt Gill

The importance of periodically testing your spray pattern is well established and it is now a component of NAAA’s new Certified-Professional Aerial Applicator Safety Steward (C-PAASS) program. However, many applicators who wish to attend an Operation S.A.F.E. clinic are unable to do so. There may be a timing conflict with the clinic, or there may simply be no clinics regularly offered nearby. For folks in this situation, a new software tool and simple sampling protocol are available to help you perform your own spray pattern testing. The materials and methods used are almost identical to that of a standard Operation S.A.F.E. clinic, except that tightly spaced sampling cards are used in lieu of string and only a single ground helper is required. After processing the cards, the software tool provides swath-width and uniformity information as well as droplet spectrum data. With your data in hand, if you choose to remotely consult with an Operation S.A.F.E. Analyst, they may also record your official participation in Operation S.A.F.E.

Bio: Matt Gill is an Extension Specialist at the University of Illinois and has served as an Operation S.A.F.E. Analyst since 2011.
Title: Effect of Application Rate on Fungicide Efficacy from an Aerial Application for Control of Sheath Blight in Rice
Authors: Daniel E. Martin, Chenghai Yang, Xin-Gen Zhou, Randy Price, Bradley Reed

Ever wondered if putting out a product at 2 GPA could work just as well as an application at 5 GPA? Applications at lower volumes not only save time and money, but also can make aerial applications more timely so that pests are controlled before they can do additional damage. The objective of this study was to determine if lower application rates of fungicide for control of sheath blight in rice can be just as effective as higher application rates. Aerial applications were made at 2 and 6 GPA. Efficacy of disease control was evaluated by plant pathologists at the Texas A&M AgriLife Research Station in Beaumont, Texas. In addition, aerial images were taken of the field, before and after treatment, to assess control. Results of the 2nd year of this study will be presented and discussed.

Bio: Dr. Martin is a Research Agricultural Engineer with the USDA-ARS Aerial Application Technology Research Unit and has over 30 years of training and experience in aerial spray application technologies for precision agriculture. He has authored/coauthored over 50 journal articles and has given over 100 technical presentations at regional, national, and international forums. He has held various leadership positions in professional societies and is recognized as a leading authority in manned and unmanned aerial application systems for precision agriculture and pest management.

Didn't make it to a previous NAAA Ag Aviation Expo? Click the links below to review the previous Aerial Application Technical Session Presentations.