Nozzle type effect on soybean canopy penetration

A spray track was designed and built to conduct replicated laboratory and field studies to compare different nozzle configurations on the ability of each to achieve lower canopy spray coverage. The purpose was to determine which nozzles might be more affective in preventing or controlling Asian Soybean Rust. Twenty nozzle types were compared in the lab and twelve nozzle types were compared in the field trials. All comparisons were at 187 L ha-1 and at a spraying speed of 16 KPH. Orifice size and operating spray pressure for each nozzle was adjusted to maintain the desired spray droplet size (200-300 microns VMD) at the calibrated flow rate of 2.5 LPM (187 L/Ha at 16 KPH). A tank mix solution of water and non-ionic surfactant was used for each comparison to simulate a field spraying scenario. For the field trials a fungicide was added to the solution to further simulate a field spraying scenario. Water Sensitive Paper and DropletScan™ was used to measure and compare VMD, percent area coverage (PAC), and number of droplets per square centimeter (DPS). In the laboratory trial, significant differences were found with PAC comparisons ranging from 5.1 to 1.6 percent. The TT11006 sprayed at 344 kPa had the most coverage. Significant differences were also found with number of D/SC with the TT11004 at 655 kPa the highest (145.5). In the field trials, significant differences were found with percent area coverage comparisons ranging from 10 to 6 percent. The TT11005 sprayed at 517 kPa had the most coverage. Significant differences were also found with number of D/SC with the TT11004 at 655 kPa the highest (43). In both experiments the single nozzle designs on average provided more coverage than the double nozzle designs. Actual measured VMD’s for all the nozzle treatments in both experiments were higher than expected. The twin or double nozzle treatments had the smaller VMD’s.