Droplet Distribution and Weed Control Efficacy of Unmanned Aerial Vehicle Sprayer in Wheat Crop

Herbicide application with Unmanned Aerial Vehicle (UAV) is among few breakthroughs due to drift risk and loading capacity limitations. This study explored a perspective of using UAVs to spray herbicides. Effects of different treatments (control, knapsack sprayer, knapsack sprayer with adjuvant, UAV sprayer, UAV sprayer with adjuvant) were observed in pre- and post-herbicide spray applications in wheat crop to compare droplet distribution pattern and Phalaris minor weed control efficacy of UAV sprayer with a knapsack sprayer, and its effect on yield of wheat (Triticum aestivum L.) crop. Uniformity Coefficient was found in the range of 1.80 - 2.25 using a UAV sprayer, and was similar (1.18 - 2.12) to that for the use of knapsack sprayer. However, volume median diameter (VMD) of UAV sprayer was in the range of 437.33 µm to 540.67 µm, while it was in the range of 670.33 µm to 768.33 µm in case of knapsack sprayer. The droplets of UAV sprayer with adjuvant and knapsack sprayer with adjuvant were bigger in size as compared to treatments without adjuvant. Least Phalaris minor weed density after 60-day crop was observed in the case of UAV sprayer with adjuvant treatment, but there was no significant difference between UAV sprayer and knapsack sprayer in weed control density. Higher yield was observed with UAV sprayer treatments as compared to knapsack sprayer and control treatments.