ARS | Publication request: Verification of a variable rate sprayer for nursery liner applications

Submitted to: ASABE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: August 22, 2011
Publication Date: August 24, 2011
Citation: Jeon, H., Zhu, H., Derksen, R.C., Ozkan, E., Krause, C.R. 2011. Verification of a variable rate sprayer for nursery liner applications. ASABE Annual International Meeting, 8/7-10/11, Louisville, Kentucky. Paper No. 1110497.

Technical Abstract: An experimental variable-rate sprayer designed for liner applications was tested by comparing its spray deposit and coverage, and droplet density inside canopies of six nursery liner varieties with constant-rate applications. Spray samplers, including water sensitive papers (WSP) and nylon screens, were mounted inside tree canopies to collect spray deposit and coverage from variable- and constant-rate (555 and 1,110 L/ha) applications. Models for estimating spray volume saving of the sprayer compared to a constant-rate and Tree-Row-Volume (TRV) based rate applications were developed for various liner canopy sizes and tree spacing. The accuracy of the model was validated with the field test data. For the liner trees tested, the variable-rate sprayer delivered 151 to 359 L/ha application rates while the conventional constant-rate application required 1,110 L/ha. Due to substantially lower spray output, the variable-rate application had relatively lower but sufficient spray deposit, coverage, and droplet density than the constant-rate applications. Also, the variable-rate application had significantly less variations in spray deposit within the canopies of different size trees. Therefore, the newly developed variable-rate sprayer would bring great reductions in pesticide use and safeguard the environment for the nursery liner production.