Development of a Battery-Operated Knapsack Sprayer for Tall Crops

The challenges for spraying in tall crops like maize and cotton with conventional knapsack sprayers are low field capacity, higher risk of chemical exposure, uneven spray distribution and operator fatigue. To address these issues, a sprayer with adjustable spraying height to accommodate varying crop heights was designed and developed. Its performance was assessed in the laboratory as well as in the actual field conditions with maize crops, and ergonomic evaluations were conducted to check the operator's comfort. The developed sprayer had an actual field capacity of 0.365 ha/h, field efficiency of 78.2% and application rate of 198.87 l/ha, surpassing the conventional knapsack sprayer's figures of 0.17 ha/h, 77.27%, and 324.32 l/ha, respectively. Furthermore, it demonstrated a lower work pulse (29 beats/min), reduced oxygen consumption rate (0.89 l/min), and decreased energy expenditure rate (18.55 kJ/min) compared to the normal knapsack sprayer (31 beats/min, 0.93 l/min, and 19.41 kJ/min). Operator discomfort scores were also lower with the developed sprayer. These results highlight its higher field capacity and ergonomic advantages over the conventional knapsack sprayer, rendering it suitable for effective spraying in taller crops like maize while contributing valuable insights to promote operator well-being.