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United States Department of Agriculture

Agricultural Research Service

Research Project: Pesticide Application Technologies for Spray-drift Management, Maximizing In-field Deposition, and Targeted Spraying

Location: Crop Production Systems Research

2012 Annual Report

1a. Objectives (from AD-416):
Objectives are: 1) Control off-target drift and enhance penetration of active ingredients, such as fungicides and biological control agents, into crop canopies; and 2) Develop remote sensing methods, utilize and evaluate Global Positioning Systems (GPS), develop methods amenable to rapid image processing, and evaluate flow control systems to support variable rate aerial application.

1b. Approach (from AD-416):
This project seeks to advance application technology through improvements in 1) drift management technology, 2) technologies for improved within-canopy deposition, 3) use of low-altitude remote sensing to identify stressed plants, and 4) performance of variable rate aerial application systems. While drift management is a concern for all pesticide applications, it is of particular concern for aerial applications. The potential for drift is greater for aerial application due to higher altitudes of spray release and greater air turbulence in the wake of the aircraft. Determination of optimal spray release height will be a goal, as the effect of this variable on within-canopy deposition and off-target drift has not been considered adequately. Experiments for both drift and deposition will attempt to reduce confounding of treatment data with environmental effects, preserving statistical precision of the experiments. Penetration of sprayed material to the lower portions of the canopy is critical for control of fungal spore diseases like Asian Soybean Rust (ASR). Studies will compare nozzle types paired with carefully selected formulations and tank mixes for spray penetration. The deleterious effects of off-target herbicide drift to cotton will be detected using hyperspectral, multispectral, and thermal remote sensing techniques. Evaluation of variable rate aerial application systems will be continued and improvements will be made through interaction with system component manufacturers. Experiments are also proposed to demonstrate the validity of techniques developed.

3. Progress Report:
Temporal data have been analyzed from a tall weather tower that indicate vertical profiles for air temperature and wind speed. A subset of these data were analyzed to provide pilots with guidelines on weather conditions and times of the day not to spray, to reduce the potential for far-field off-target movement of spray caused by temperature inversions. Updated data acquisition hardware is being configured for the weather tower. Three remote sensing systems used for plant stress monitoring were configured for both piloted agricultural aircraft and unmanned aerial vehicles (UAV). A camera triggering and navigation system for a high resolution multispectral camera system was improved using new technologies installed on the aircraft. A six-channel multispectral camera has been configured on the aircraft. A three-band multispectral camera system has been evaluated on a Parafoil-based UAV. The cameras were operated over three farms to acquire imagery. The feasibility of using a nozzle that does not shear the droplet is being investigated for application of non-toxigenic Aspergillis Flavus fungus for biocontrol of mycotoxins. Special preparations were developed in the ARS Biological Control Lab, Stoneville, MS, and their physical properties are being evaluated by ARS scientists in the USDA ARS Crop Production Systems Research Unit. A study in the greenhouse was conducted to further characterize the onset of soybean injury caused by application of glyphosate herbicide using hyperspectral imaging and measurements of plant leaf chlorophyll. Hyperspectral imagery were analyzed to characterize the onset of the soybean injury, and results were also obtained from spectroradiometery and a chlorophyll meter. A field experiment was conducted to characterize crop injury caused by ground-sprayed dicamba at different rates using remote sensing. This experiment evaluated refined remote sensing technology to characterize the onset of the crop injury, to study the relationship between crop injury and yield, and to collect data for a new crop injury model. The crops concerned in the experiment are soybean and cotton.

4. Accomplishments
1. Multispectral and hyperspectral imaging for detection of crop injury. A color infrared multispectral imaging system successfully indicated the onset of crop stress due to variable-dose herbicide application. This system was configured with a new high-performance navigation system to trigger image acquisition only over the fields of interest so large image files could feasibly be stored. A new hyperspectral imaging system was successfully employed to determine herbicide-induced crop response to applied Dicamba at different application rates. Data obtained will be useful to indicate dose response and potential yield reduction due to drift of herbicide.

2. Times to avoid aerial spraying during temperature inversions. Wind and temperature data at two elevations can be used to determine when pilots should avoid spraying during an atmospheric temperature inversion. Scientists at the USDA-ARS Crop production Systems Research Unit in Stoneville, MS, obtained data from a weather tower to make recommendations to pilots on times of day to avoid far-field drift of pesticide. Preliminary recommendations indicate that aerial applicators can spray when the air temperature measured at ground level rises 3°F from the morning low and until the afternoon temperature declines 5°F from the afternoon high in the summer months. Results will be useful for pilots to indicate time windows within which it is safe to spray to avoid off target movement of spray.

Review Publications
Huang, Y., Thomson, S.J. 2011. Characterization of in-swath spray deposition for CP-11TT flat-fan nozzles used in low volume aerial application of crop production and protection materials. Transactions of the ASABE. 54(6):1973-1979.

Huang, Y., Thomson, S.J. 2011. Characterization of spray deposition and drift from a low drift nozzle for aerial application at different application altitudes. International Journal of Agricultural and Biological Engineering. 4(4):1-6.

Huang, Y., Thomson, S.J., Molin, W.T., Reddy, K.N., Yao, H. 2012. Early detection of soybean plant injury from glyphosate by measuring chlorophyll reflectance and fluorescence. Journal of Agricultural Science. 4(5):117-124.

Last Modified: 06/23/2017
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