BIOLOGICAL, MICROCLIMATE, AND TRANSPORT PROCESSES AFFECTING PEST CONTROL APPLICATION TECHNOLOGY
Location: Application Technology Research Unit
Title: An experimental variable-rate sprayer for nursery and orchard applications
Submitted to: ASABE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: August 22, 2011
Publication Date: August 24, 2011
Citation: Chen, Y., Zhu, H., Ozkan, E., Derksen, R.C., Krause, C.R. 2011. An experimental variable-rate sprayer for nursery and orchard applications. ASABE Annual International Meeting. Paper No. 1110497. http://asae.frymulti.com/azdez.asp?search=1&JID=5&AID=37207&CID=LOI2011&T=1.
Most chemical applications in orchards and ornamental nurseries are not target-oriented, resulting in significant loss of pesticides and contamination of the environment. To avoid over- and under-application of chemicals, sprayers must be designed to apply the appropriate amount of pesticide based on the tree canopy characteristics such as tree height, width, volume, and foliage density. A precision air-assisted sprayer with variable flow rate of individual nozzles was tested for treating ornamental nursery and fruit trees. The sprayer was developed using a modified conventional air-assisted orchard sprayer by implementing a laser scanner to detect canopy characteristics, five-port air-assisted nozzles coupled with pulse width modulation (PWM) solenoid valves to deliver spray, and an automatic flow rate controller to minimize pressure fluctuation. Sprayer treatments included the new precision sprayer, the same precision sprayer without the intelligent control activated and a conventional, axial flow, air blast sprayer in an apple orchard at three different growing stages. Measurements were made for spray deposition and coverage inside canopies, losses on the ground and beyond target trees, and airborne drift downwind from the target trees. Compared to conventional sprayers, the variable-rate sprayer produced relatively uniform spray coverage and deposition inside canopies, and reduced spray volume by 47% to 73% with significantly less off-target losses on the ground, through gaps between trees, and in the air.