Air Assistance and Electrostatic Spraying in Soybean Crops

Abstract

This study aimed to evaluate the efficiency of air assistance associated with electrostatic spraying in terms of spray deposition and yield (Experiment 1), and the coverage and droplet density on soybean crops at different working speeds (Experiment 2). The treatments in Experiment 1 corresponded to combinations of electrostatic systems associated with air assistance at three airspeeds (21, 25, and 30 m·s−1) plus a conventional treatment without electrostatic or air assistance. The treatments in Experiment 2 corresponded to three working speeds (3.3, 4.2, and 5.0 m·s−1) with or without the use of an electrostatic system. All applications were performed with a self-propelled sprayer, delivering 75 L·ha−1 with ATR 2.0 nozzles. A blue tracer, detectable as absorbance with a spectrophotometer, was added to the spray solution to evaluate deposition. The results indicate that an air assistance at 21 m·s−1 plus electrostatic system increased the amount of spray deposited on the middle and top leaves of the plants in relation to the conventional system, with yield increments of up to 621 kg·ha−1. The slowest working speed (3.3 m·s−1) combined with air assistance and an electrostatic system provided the greatest spray deposition, droplet coverage, and density on the bottom leaves of soybean crops.

Keywords

• spray deposition
• coverage
• droplet density
• <i>Glycine max</i> L. Merril
• yield