Optimization of Operational Parameters for Agricultural Drone Spraying in Maize Crops

Abstract

This research on an agricultural drone sprayer for maize crops aimed to standardize various operational parameters—such as spraying height, discharge rate, and drone forward speed—based on metrics like effective swath width, droplet density, Volume Median Diameter (VMD), Number Median Diameter (NMD), Homogeneity Factor (HF), spray volume consumed, effective field capacity, field efficiency, and spray deposition at two crop stages (stage 1: 60 DAS and stage 2: 70 DAS). Field experiments indicated that droplet density decreased as spraying height, discharge rate, and forward speed increased. The maximum droplet densities were 12.39, 12.91, and 12.80 droplets/cm² at a spraying height of 2 m, a discharge rate of 100%, and a forward speed of 3 m/s, respectively, for crop stage 1. Average VMD and NMD ranged from 234 µm to 263 µm and 139 µm to 148 µm, respectively, across different parameter levels. An HF close to one was achieved, with values of 1.71, 1.59, and 1.70 at a spraying height of 2.5 m, a discharge rate of 80%, and a forward speed of 5 m/s, respectively, for both stages. Spray volume consumption per hectare decreased with increasing spraying height, decreasing discharge rate, and increasing forward speed. The maximum effective field capacity (EFC) was found as 2.84 ha/h with 80% field efficiency (FE) at a spraying height of 3 m, and 3.02 ha/h with a 73.08% FE for crop stage 1 and 2. Based on the study, the optimal operational parameters were standardized as a spraying height of 2.5 m, a discharge rate of 80%, and a forward speed of 5 m/s.The drone sprayer significantly reduced time, covering one hectare in only 0.32 hours compared to 11.62 hours with a battery-operated manual knapsack sprayer. This research provides valuable insights for optimizing agricultural drone spraying parameters, potentially improving the efficiency of drone sprayers in crop protection practices.