Optimization of Operational Parameters of Power Sprayer for Spraying in Mango Plantation

Portable horizontal triplex pump (HTP) power sprayer is dominant in Konkan region especially for mango orchard spraying. A field experiment was carried out to optimize the performance of power sprayer in mango orchard. The selected mango orchard had 4.5 - 5.0 m height trees planted at 10 × 10 m spacing. Water sensitive papers of 44 × 44 mm size were stapled on up and down sides of tree leaves at different canopy positions to catch the spray deposition samples. The selected power sprayer was equipped with horizontal triplex plunger pump having power 3 kW and speed 1000 rpm. The experiment was conducted by varying the suction pressure from 980 to 1961 kPa, nozzle-to-target distance from 0.50 to 0.60 m, travel speed in range of 0.30 to 0.60 m s-1. The two nozzle types, viz., hollow and solid cone nozzle were used in the experiment. The statistical optimization was carried out using response surface methodology (RSM) with Box Behnken, randomized subtype design with total 34 experiments. The optimum parameters viz., pressure, nozzle distance and travel speed were 1471 kPa, 0.55 m and 0.45 m s-1, respectively for power sprayer with hollow cone type nozzle. At these optimized levels, the dependent variables viz., droplet size, droplet density, uniformity coefficient and spray deposition were observed as 291.4 µm, 120.12 droplets cm-2, 1.78 and 0.64 µl cm-2, respectively. These optimized parameters resulted in improved pesticide spraying efficacy with better coverage and improved safety during spraying operation in the mango orchard.