ELECTROSTATIC CHARGING OF AERIAL SPRAY OVER COTTON

Electrostatically charged aerial spray studies were carried out over c otton fields. The study was planned and structured to obtain needed en gineering information regarding the role and domain of applicability o f this technology/methodology for aerial application. Spray deposition measured directly and separately from the top and bottom surface of c otton leaves was used to quantitatively evaluate three charging protoc ols: (1) bipolar, (2) alternating polarity, and (3) no-charge. The bip olar spray charging protocol gave significantly higher deposits on the cotton leaves than the no-charge or alternating polarity protocol. Me an deposit levels were 4.3 times higher with bipolar charged spray (Q/ M = +/- 2.64 mC/kg) compared to no-charge spray (Q/M = 0 mC/kg). Bipol ar charging also showed a 3.0-fold increase in deposit over the altern ating polarity protocol (Q/M = 2.64 mC/kg @ 0.29 Hz). Bipolar charging was also demonstrated to be effective in increasing plant canopy pene tration and exhibiting a leaf wrap-around effect. As expected, deposit means were greater on the tops as opposed to the bottoms of the leave s, and upper canopy deposits were greater than lower canopy deposits. The experiments also showed a significant replication effect. The reas on for it was not apparent. The large scale electric field effects ass ociated with bipolar charging present information for much further tho ught and study.