SPRAY UNIFORMITY TESTING OF UNMANNED AERIAL SPRAYING SYSTEM FOR PRECISE AGRO-CHEMICAL APPLICATIONS

Abstract

Excessive agro-chemicals are being used to enhance agricultural production to meet the food security challenge with increasing population. Gaps or overlaps in the spraying patterns can result in under or over application of pesticides thus causing environmental hazards.Conventional sprayers have uniform spray drift that is less effective for heavy canopies. Alternatively, unmanned aerial system (UAS) are being used for crop monitoring and management (spraying insecticides/pesticides) however proper spray height and nozzle opening needs investigation. In this study, a hexa copter unmanned aerial agro-chemical spraying (UAAS) system was tested at different heights and nozzle openings to determine spray uniformity in the field conditions. Operating height of 1.5 m, 2.0 m, 2.5 m and 3.0 m with spray nozzle opening (discharge rate) percentages of 25, 50, 75 and 100% were investigated for variable wind speeds ranging between 1 m/s to 5.8 m/s. Colored spray was used to get impression of spraying droplets on sensitive papers placed for the purpose. Spray dots were counted to get the spraying uniformity at different heights and wind conditions. The hexa copter UAAS system provided a good uniformity and coverage area at operating height of 1.5 m with 50, 75 and 100% spray nozzle opening under wind conditions varying from 1 m/sec to 5.8 m/sec. This investigation provides a guideline to the farmers and service providers entering into the business of spraying through UAS