Comparison of spray nozzles in terms of spray coverage and drop distribution uniformity at low volume

This study was conducted to compare the spray coverage rate and spray uniformity of seven different types of hydraulic nozzles (standard flat fan nozzles, ST; multirange nozzles, LU; air induction nozzles, IDK; twinjet air-induction nozzles, IDKT; narrow cone-angle standard nozzles, STD; hollow cone nozzles, DC; and antidrift nozzles, AD) commonly used in pesticide applications at low application volumes. All spray applications were carried out at a constant operating pressure of 300 kPa and a low application volume of 80 L/ha. The experiments were carried out in a closed facility under controlled conditions. Spray applications were carried out with the aid of a 12-m-long linear, automatic speed-controlled spray simulator. Water-sensitive paper was used for drop sampling. The greatest spray coverage was achieved in LU nozzles and they were followed by DC and ST nozzles. The lowest spray coverage was observed in IDKT nozzles. Increasing spray coverage rates were observed with decreasing spray heights. Increasing coverage rates were also observed with decreasing forward speeds. Regarding spray uniformity, the lowest mean coefficient of variation (CV) was obtained from AD, IDK, and IDKT nozzles producing medium and coarse droplets. It was concluded based on the present findings that the spray height should be reduced to increase spray uniformity. ST, AD, and IDK nozzles have to be selected with greater forward speed in order to increase spray uniformity. However, in LU and DC nozzles, the lowest CV was obtained at low forward speeds.