Improving electrostatic pollination inside tree canopy via simulations and field tests

Artificial pollination of fruit trees can help in improving the yield and quality of the crop. A charged cloud of pollen passing around a flower can induce a concentrated electrostatic field around the flower tips, thus creating favorable conditions for the stigma to collect pollen. This study investigated the effects of flowers distribution, tree shape, charging levels, and airflow characteristics on the amount of pollen deposited artificially by an electrostatic pollinator on various tree parts. Deposition tests were made on a simulated tree constructed in the laboratory and in a commercial almond orchard where supplementation of charged pollen to conventional honeybee pollination was examined. Fruit-set and pollen germination were evaluated. The laboratory tests showed that charging the pollen can cause an order-of-magnitude increase in deposition on all branches, although more pollen was deposited in regions closer to the applicator or the periphery. The enhancement due to electrostatic pollination was more moderate in the field tests, but was greater in the medial than in the outer parts. The field tests showed also that pollen charging can improve pollen germination and fruit-set.