Abstract:
Abstract: In order to explore the effect of spray droplet deposition and applications of N-3 unmanned aerial vehicle (UAV) at late maize growth, spray test was done at different working heights and multi-swath lap joint of different spraying swath. Research on fog drop interception by maize canopies during pesticide spraying can provide technical data for the optimum design, performance improvements, and correct use of the sprayer. A solution of Rhodamine-B mixed with water in 0.1% concentration was selected for instead of the pesticide to spray maize fields, monitoring wind speed of flight direction refer to meteorological station monitoring method in spraying test, as well as humidity and temperature. Droplets were collected along the altitude direction of maize growth in four layers using mylar card with a diameter of 90 mm. The deposit of spraying fog drop on maize plant in every layer was measured by means of a fluorescence spectrophotometer to abtain the regularities of distribution of droplet deposition between different layers in maize canopies. The analysis results showed that: the total quantity of droplet deposition at the targets reached minimum when the working height was 5 meters. Meanwhile, dispersion had a largest value of 0.17. The total quantity of droplet deposition at the targets reached maximum when the working height was 7 meters. Meanwhile, dispersion had a smallest value of 0.10. The effects of spray droplet deposition and uniformity were different at the top, upper, ear and bottom of maize canopies when the working height was different, the quantity of droplets deposition in upper and ear of maize canopies was higher than that at the top and bottom of the maize. The deposition percentage of multi-spraying swath was 38.4% and 38.1% respectively, when the spraying swath was 5 meters and 9 meters under the same working height, and CV was 41% and 34.4%, respectively. The deposition on maize canopies was maximum when the height of working flight was 7 m. The connection of the width of spraying swath was the best when the spraying swath was 7 m, which coefficient of variation was 25%. Flight height and spraying swath of unmanned helicopter had a significant impact on the deposition uniformity, the results can provide guidance for the actual production application at late maize growth. Therefore, considering droplet deposition characteristics and the spray effect, 7 meters in the working height and 7 meters in the spraying swath should be chosen as reference of spraying pesticides. The research also has a significance in reasonably spraying pesticide, improving the efficiency of spraying, increasing the pesticide-applying efficiency and prevention and control of plant diseases and insect pests outbreaks in large areas.