Electrostatic application of pollen sprays: effects of charging field intensity and aerodynamic shear upon deposition and germinability

Pollination deficiencies limit the biological production efficiency of certain high-value agricultural crops. To enhance pollination, an aerodynamic-electrostatic spray process has been developed which incorporates electric forces to transfer ~60-μm pollen grains to receptive stigmatic surfaces of flowers. Osmotically balanced carrier-liquid suspensions of almond pollen, pneumatically atomized at up to 276 kPa and induction charged to 12 mC/kg in 1.6-MV/m applied fields, are shown to maintain at least 80% germinability upon electrostatic deposition. Compared with uncharged spray, charged pollen deposition was significantly (∝=0.01) increased 5.6-fold as averaged across various target orientations. For difficult targets parallel to the spray´s air-carrier stream, the electrodeposition benefit for pollen was maximum (12-fold increase) and air-pressure effects were most pronounced