Drift and deposition of pesticide applied by UAV on pineapple plants under different meteorological conditions

Spray drift has always been a focus research area in the field of unmanned aerial vehicle(UAV)application.Under the fixed premises of UAV operating parameters,such as height,speed and spraying liquid,the droplet drift is mainly affected by meteorological conditions.In this research,the spray drift and deposition tests were conducted using a QuanFeng120 UAV in a pineapple field under various different meteorological conditions.The experimental results showed that with the changes of UAV operating height and wind speed,the start position of the in-swath deposition area changed 4 m in the extreme situation.The percentage of the total spray drift was from 15.42%to 55.76%.The position of cumulative spray drift that accounted for 90%of the total spray drift was from 3.70 m to 46.50 m relative to the flight line.According to the downwind spray drift curve,the nonlinear equations of the same type under the four operating conditions of the UAV were fitted.The spray drift and the deposition of UAV application were significantly affected by different meteorological conditions and UAV operating heights.The results could provide a theoretical basis for UAV spraying in pineapple plants and support for spray drift control and prediction.

Evaluation of droplet deposition and effect of variable-rate application by a manned helicopter with AG-NAV Guía system

The variable-rate application is an important aspect of precision agriculture.In order to determine the regular patterns of droplet deposition and compare the actual variable-rate spraying effect of the AS350B3e helicopter with the AG-NAV Guía system,spray tests were conducted with different operating parameters and operating methods.In this study,the deposition distribution of droplets in the effective swath area was evaluated for six single-pass applications at four different flight velocities.The effects of adding adjuvant on droplet deposition,drift and droplet size were compared,and the actual variable effect of the forth-back application was verified.The analysis results showed that the position of the effective swath area was affected by natural wind velocity and wind direction,and would shift to the downwind direction area from the helicopter route of a different degree.The effective swath width increased slowly and then decreased sharply with the increase of flight velocity.It was found that flight velocity of 100 km/h was the peak inflection point of effective spray width variation.Moreover,the effect of flight velocity on the distribution uniformity of droplet deposition in the effective swath area was not significant.In the single-pass application of 90 km/h,adding adjuvant could increase droplet size in the effective swath area.The deposition increased by 8.98%,and the total drift decreased by 28.65%,of which the upwind drift decreased by 28.31%and the downwind drift decreased by 29.06%.In the forth-back application of 90 km/h,the error between actual application volume and system setting dose was 12%.The results of this study can provide valuable references for future research and practices on variable-rate aerial applications by manned helicopters.

Effect of UAV prewetting application during the flowering period of cotton on pesticide droplet deposition

Prewetting process can reduce the contact angle between the droplet and the leaf blade,so that the droplet can more easily wet and spread,thereby increasing the quantity of deposition.To improve the effectiveness of pesticides on cotton leaves,prewetting by single-rotor electric unmanned aerial vehicles(UAV)was studied,focusing on the effects of pesticide deposition on cotton leaves during the flowering period.Cotton leaves in 0°–30°,30°–60°,60°–90°leaf blade angle ranges(angle between the leaf blade and the horizontal plane)were examined.In the first experiment,four different prewetting volumes(0,1.6,3.2 and 4.8 L)were sprayed by a singlerotor electric UAV on four cotton plots(plots A–D)each with an area of 120 m^2,and then each area was sprayed with a 0.8%(w/v)ponceau 2R solution by another singlerotor electric UAV.The results revealed that with no prewetting,droplet deposition quantity decreased with increasing leaf blade inclination.After prewetting,the mean droplet deposition quantity on plots B,C and D increased by 39.8%,9.7%and 24.9%,respectively.The prewetting rate of 1.6 L per 120 m^2 had the most significant effect on improving the deposition of droplets.It was also found that the mean droplet deposition quantity in each leaf blade angle range increased after prewetting.For the leaf blade angle range 60°–90°,this increase was the most pronounced,with 0.043,0.062,0.057 and 0.048 μL·cm^(-2)in plots A–D,respectively.Also,droplet deposition uniformity in the leaf blade angle range 60°–90°was better after prewetting.These results should provide a valuable reference for future research and practice to improve the effectiveness of pesticides applied to cotton by aerial applications.