PRECISION BAND SPRAYING WITH MACHINE-VISION GUIDANCE AND ADJUSTABLE YAW NOZZLES

摘要

A system was developed for precision, ground-based application of foliar sprays to rows of small plants. The system consisted of a machine-vision guidance system that positioned spray nozzles directly above each row of small plants. An electrically actuated mechanical linkage rotated flat-fan spray nozzles about their central axes to vary the yaw angle of the fans relative to the direction of travel. The nozzle rotation effectively changed the width of the spray pattern relative to the direction of travel and allowed the spray band to be adjusted to match the width of the target plants. The system was evaluated on young stands of tomatoes and lettuce by measuring spray deposition on the plants and surrounding soil. The precision system allowed spray application rates to be reduced by 66 to 80% and increased spray deposition efficiency on the target plants by 2.5 to 3.7 times greater than conventional broadcast spraying. Nontarget deposition on soil surfaces was reduced by 72% to 90%. Airborne displacement of spray liquid from the spray boom, as measured by collection strings surrounding the boom structure, was reduced by 62 to 93%. The reduction in displacement suggested that spray drift from precision applications could be significantly less than that from conventional applications.