Real time variable rate sprayer: Its development and comparative analysis of spray coverage with conventional orchard sprayer.

Fruit yield depends on spray management techniques, i.e., uniformity, time, quantity, and precision of application. Due to variability in tree canopies, it is difficult to manage spray applications properly. Old orchard sprayers apply continuous spray without differentiating between size, density and spaces between canopies, causing drift losses and environmental hazards. Keeping this in view, conventional sprayer was modified to double sided vertical boom type sprayer, which was equipped with infrared sensors, solenoid valves and Arduino Mega microcontroller, programmed with Arduino IDE. Vertical booms consist of eight nozzles, four on each side, height and width of which were adjustable according to groove age. Each pair of nozzles was controlled independently for variable rate of application with respect to canopy characteristics. Spray coverage and vertical distribution of real time variable rate sprayer (RTVRS) were analyzed and compared with conventional sprayer. Average spray coverage at discharge rates, 800 and 1200 L/hr was 5.37, 9.18 μL/cm² with RTVRS and 3.87, 6.63 μL/cm² with conventional sprayer respectively. Vertical distribution was measured for 3 m canopy height, which was divided into 3 equal sections. Percent spray deposits of RTVRS were 22.2%, 54.06%, 23.78% and conventional sprayer were 17.75%, 59.03%, 23.17% from lower to upper section, while the skewness towards top was -0.35 and -0.48 respectively. RTVRS showed promising results as compared to conventional sprayer and better replacement to address the current issues related to farmers and environment. Moreover, the cost of production is also 5 to 10 times less than imported crop sprayers. [ABSTRACT FROM AUTHOR]