Pulsed-jet microspray applications for high spatial resolution of deposition on biological targets

In agricultural spraying, where discrete targets and nontargets are present in a localized region, high spatial resolution of liquid deposition is essential for selective treatment. Microspraying with small jets can provide high resolution in spray dose and position. Pulsed microspray jets were created with various orifice sizes and duration of liquid emission and deposited with various orifice-to-target distances. Formulations included surfactants that increase area covered onto plant surfaces for increased herbicide efficacy, and polymers to inhibit splash during deposition. Kromekote(TM)cards were used as the deposition target. Image analysis measured deposition area and centimeter-scale splashing, i.e., "microdrift" from the pulsed jets. Liquid properties were measured; Reynolds (Re), Weber (We), and Ohnesorge (Oh) numbers were calculated. Formulations containing polyethylene oxide polymer were more effective at reducing microdrift than polyacrylamide polymer, and silicone surfactant increased spreading compared to an oil-based surfactant.