Electrostatic technology for pesticide application. Prototype characterization and validation in super-intensive olive crops

Electrostatic technology for agricultural crops has been studied in recent decades to improve pesticide deposition by applying voltage to droplets, which maximizes the amount of product reaching the deepest areas of the canopy through attractive forces. However, few studies perform a comprehensive laboratory characterization of a sprayer followed by field validation in order to explore the possibility of reduced amount of chemicals, specifically for super-intensive olive cultivation. This study aimed to conduct a laboratory evaluation of an electrostatic sprayer prototype designed for three-dimensional hedge crops and validate its performance through field experiments. Sprayer configurations associated with activated or deactivated electrostatic system (ES vs. NES, respectively) were tested. The characterization included airflow evaluation, product distribution profile, charge-to-mass ratio (CMR) quantification, and deposition trials, varying application parameters such as liquid pressure, airflow setup, and distance under controlled environmental conditions. A differentiation between adaxial and abaxial areas of the artificial target during deposition assays was also carried out. Finally, field trials compared the electrostatic sprayer to conventional application methods, providing practical insights into pesticide reduction efficiency. Laboratory results showed no differences in flow rate (L min −1 ) between ES and NES configurations at any tested pressure. The total accumulated volume from the vertical distribution profile showed variations associated with airflow configuration and liquid pressure as a function of distance. Deposition results revealed higher coverage and deposition when the electrostatic system was activated, regardless of distance or height, with a 70 % increase in abaxial areas compared to the NES. Field trials in super-intensive olive orchards revealed good performance in terms of coverage and deposition on artificial receptors and leaves after application with the electrostatic equipment, particularly at the highest application dose (163.3 L ha −1 ) compared to the conventional spraying (466.3 L ha −1 ), highlighting a 60 % reduction in application volume. Additionally, ground losses were significantly lower with the electrostatic sprayer, as coverage and deposition at the base of the trunk were substantially reduced compared to conventional equipment. • Electrostatic spraying was tested on a prototype sprayer for three-dimensional crops. • The sprayer was characterised in the laboratory and validated in field trials under different sprayer settings. • Electrostatic system activation significantly increased deposition in unexposed areas in laboratory conditions. • Electrostatic spraying improved canopy penetration in super-intensive olive orchards compared to conventional application. • Application volume was reduced without compromising deposition efficiency, with lower endodrift and ground losses observed.