Design, Modeling, and Performance Evaluation of a Manual Gravitational Fertilizer Spreader with Linear Kinetic Energy Transmission System

The development of small-scale mechanization equipment for hand-cultivated farms and mountainous regions is essential for improving productivity in the agricultural sector. This research focuses on the design, construction, and evaluation of an innovative manual fertilizer spreader that operates without an external power source, based on the principles of gravitational flow and linear kinetic energy transfer. The system consists of a 20-liter backpack hopper, a flow control valve, a flexible guidance tube, and a 1-meter rigid launch tube. The flow mechanism was modeled based on Beverloo's Law, and energy transfer was modeled using Newton's Second Law and the Work-Energy Principle. Field tests in paddy fields of IRAN Golstan province showed the device, weighing under 1 kg, is capable of spreading fertilizer over 1.5 hectares per hour with a dispersion radius of 4 meters. Results indicate that a launch angle of 45 degrees and a horizontal oscillation range of 135 to 140 degrees provide the optimal conditions for a distribution uniformity of 78%.