Development of a battery-supported sprayer- cum-weeder

In India, insects, diseases and weeds cause major losses in crop yield. Weed control with hand tools is labor-intensive and inefficient, highlighting the need for mechanical weeders to improve productivity. Similarly, pest and disease management requires frequent pesticide and fungicide spraying, which adds labor and cost. Since ineffective weed management is a major hurdle in crop and vegetable production, mechanical weeders are essential to boost yield and efficiency. A machine that integrates both weeding and spraying can reduce effort, save time and enhance crop yield sustainably. Therefore, a new machine that functions as both a sprayer and a weeder was developed and tested in a study. It was intended to manage particular crop parameters such as row spacing and plant height for different horticultural crops. The machine is mounted on a strong frame (1109 mm × 600 mm × 1000 mm) and is powered by a 650 W PMDC motor supplied by 42 V LifePo4 lithium -Ferro phosphate battery, while the spraying unit operates with a 12 V lead-acid battery. For weeding, interchangeable blades (B₁ weeder blade and B₂ tiller blade) are attached using nuts and bolts, with B1 weighing 4.34 kg and B2 weighing 7 kg. The sprayer system consists of a double motor diaphragm pump (7 bar pressure), a brass hollow cone nozzle assembly with four nozzles (each with six holes) and a 1.8 m wide boom mounted 700 mm above the ground, connected to a 25 L tank through a 1.8 m hose pipe of 20 mm diameter. The machine can operate at a speed of 2-2.5 km/h with a ground clearance of 370 mm, supported by wheels and a chain-sprocket transmission system. The overall machine weight is 77 kg for the weeder and 102 kg when equipped with the sprayer tank. The total cost of fabrication was ₹60,350, with an operating cost of ₹75.26 per hour or ₹242.77 per hectare. Economic analysis indicated a payback period of just over three years, confirming the machine’s viability for small and marginal farmers.