2010 Annual Report
1a.Objectives (from AD-416)
To develop two advanced and affordable spray systems that employ intelligent technologies to continuously match system operating parameters to crop characteristics, insect/disease pressures and microclimatic conditions during pesticide applications.
1b.Approach (from AD-416)
Will develop two intelligent expert precision spraying systems implementing five main components to apply the amount of pesticides as needed. The first system will be an air-assisted variable-rate sprayer to be used for shade, flowering and ornamental trees in nurseries. The second system will be a hydraulic boom variable-rate sprayer to be used for flowering container plants in greenhouses and woody ornamentals in nurseries. Due to the similarity of crop structures, the use of the first system can be expanded to other specialty crops such as fruit trees and vineyards, and the second system can be expanded to berries and vegetables. The five components will be: a sensor-controlled unit to control spray outputs that match structures of specific floral and nursery crops, an expert subsystem to assist choosing proper chemicals and application schedules, a direct in-line injection unit to inject concentrated chemicals to individual nozzles to eliminate leftover disposals, a off-target recovery unit to prevent spray off-target losses including drift beyond target areas, and a fluid delivery subsystem to discharge spray outputs with variable rates. All the operations will occur as the sprayer moves past the canopy, providing uniform spray coverage of the canopy with minimum pesticide use and off-target loss beyond the target area. Speciality Crops Research Initiative.
A series of tests to evaluate durability and detection stability of an ultrasonic sensor was carried out under cold weather exposure, wind, dust, travel speed, air temperature and spray cloud conditions. To reduce root mean square errors, a strategy to configure the sensor with spray nozzles was developed. In addition, multiple-synchronized sensors were tested for their measurement stability and accuracy as a sensing unit while detecting targets.
A real-time variable-rate experimental sprayer was developed to reduce pesticide usage by coinciding spray outputs with canopy sizes. The sprayer consisted of two parallel vertical booms, an ultrasonic sensing system, a solenoid-activated spray output modulation system, a microprocessor-based controller and a spray delivery system. The total amount of sprays delivered from all active nozzles was based on the tree size, and a particular pair of nozzles was triggered by the exposed canopy surface. The sprayer performances including accuracy of spray timing and spray modulation as well as percent spray coverage inside tree canopies were evaluated under both laboratory and field conditions.
A precision air-assisted sprayer implementing an automatic variable rate control system is in the process of development for ornamental nurseries and fruit trees. A high speed laser scanner was investigated to detect gaps between trees, and measure tree characteristics. Interfaced program between laser and computer was developed to determine the tree size and shape. Droplet size distributions from spray nozzles were measured. Laboratory and field tests were conducted to verify the accuracy of spray controller timing and modulation.