Development of a Battery-Operated Liquid Fertilizer Applicator with an Electronically Controlled Metering Device

Most farmers face high fertilizer prices and suffer economic losses due to uncontrolled fertilizer application on their farms. The common method of applying liquid fertilizer is with a watering can. The developed liquid fertilizer applicator is a battery-powered knapsack sprayer equipped with a program-based electronic metering device to deliver a more accurate amount of liquid fertilizer based on crop needs. The device includes a tank, pump, switch button, microcontroller, solenoid valve, liquid flow sensor, and lance. It was tested using two types of lance (injector-type and open-type) and compared to the traditional application method. Results showed that the uniformity coefficient exceeded the recommended 85%, with the open-type lance reaching 97.95% and the injector-type lance 96.09%. The device's actual field capacity was 248.70 m²/hr with the open-type lance and 134.96 m²/hr with the injector-type lance. Additionally, the injector-type lance's application rate and power consumption were 355.97 mL/m² and 9.26 Wh, respectively, while the open-type lance had 354.17 mL/m² and 5.17 Wh. These results indicate a higher uniformity coefficient, wider actual field capacity, and lower application rate compared to traditional methods, which had 72.74%, 110.15 m²/hr, and 538.58 mL/m², respectively. Therefore, the developed device improves liquid fertilizer application by efficiently dispensing the required amount, reducing labor and time, and cutting labor costs for the same field area compared to traditional methods.