Droplet deposition and efficiency of fungicides sprayed with small UAV against wheat powdery mildew

Abstract

Small unmanned aerial vehicle (UAV), a timely and effective pesticide sprayer, can be used to spray pesticide in a high efficiency without harming the crop, and is especially suitable for spraying for small farms and hills in Asian countries. In recent years, it has been chosen as a key and new technique for pesticide application. This paper studied the impact of UAV (UAV N-3) spraying parameters (different working height and different spraying concentrations) on the deposition of droplets on the wheat canopy and the prevention of powdery mildew. Water sensitive paper was used as the sampler to collect the pesticide droplets and image processing software Deposit Scan was used to compute the coverage rate of droplets on the wheat top layer to acquire the proportional distribution of droplets on the wheat lower layer. The experimental results showed the impact of spraying height on the distribution of droplets on the wheat upper layer was quite significant, when the spraying height was 5.0 m and the spraying speed was 4 m/s, the coverage rate of droplets on the wheat lower layer was the largest, as it was 45.6% of that on the upper layer, the droplets distribution was the most uniform, and the coefficient of variation was 33.13%. 450 g/hm 2 (dosage registered) of triadimefon SC (44%) was sprayed by the UAV, the control efficiency reached 55.1% after applying which was better than 20% and 40% of dosage decreased for each hectare, and the applying effect (35.6%) of 20% dosage decreased for each hectare had no significant difference from the applying effect (34.6%) applied by a knapsack-type electric sprayer. At 10 d after applying, the prevention effect realized by UAV was lower than that realized by a knapsack-type electric sprayer, and it may be correlated to the meteorological condition and water amount in the pesticide sprayed. Thus, when UAV spraying was chosen to prevent wheat powdery mildew under a serious disease situation, an auxiliary agent for spraying could be added to prolong the retention of pesticide on the plant surface to extend the pesticide effect. This study can provide a reference for the optimized design, performance upgrade and reasonable application of small UAV sprayers. Keywords: unmanned aerial vehicle (UAV), spraying pesticide, parameters optimization, fungicide deposition, wheat powdery mildew, control effect DOI: 10.25165/j.ijabe.20181102.3157Citation: Qin W C, Xue X Y, Zhang S M, Gu W, Wang B K. Droplet deposition and efficiency of fungicides sprayed with small UAV against wheat powdery mildew. Int J Agric & Biol Eng, 2018; 11(2): 27-32.

Research status and trends of downwash airflow of spray UAVs in agriculture

“…For instance, Zhang et al started to focus on UAV application for citrus and found the variation of droplet distribution [12] , while Tang et al concentrated on the deposition changes affected by tree shapes [13] . Similar studies regarding UAVs and spray factors include T10 UAV for wheat scab control [14] , Response Surface Method for the test of P20 UAV parameters [15] , tree shapes and flight heights for the deposition of 3W-LWS-Q60S [16] , the comparison of four types of UAVs [17] , the method of detection of effective spray swath of 3WQF120-12 [18] , different operation parameters for several stages of corns [19] , low-attitude droplets deposition [20] , drift caused by different types of UAVs [21] , deposition on pineapple trees impacted by operation parameters [22] and the control effect of wheat powdery mildew using different operation parameters [23] . Until 2019, this kind of study is still heated discussed [24][25][26] .…”

Integration of remote‐weed mapping and an autonomous spraying unmanned aerial vehicle for site‐specific weed management

“…First, the carrier volume of the UAV‐IS (151 L ha −1 ) was 20% lower and generated fewer droplets with a higher concentration of glufosinate compared to the 187 L ha −1 carrier volume of the broadcast system, likely favoring herbicide absorption by the plant . Second, and more likely, the downwash air generated by the propellers of the UAV‐sprayer favored more N. tobacco leaf movement, so leaves were exposed to the herbicide on both the adaxial and abaxial sides, effectively increasing the amount of herbicide reaching deeper into the canopy of the target plants . This latter situation was more likely to occur for N. tobacco , which has erect growth and long leaves, than for K. striata , which exhibits prostrate growth and very small leaves.…”

Converting a Fixed-Wing Internal Combustion Engine RPAS into an Electric Lithium-Ion Battery-Driven RPAS

“…Reference Fixed-wing [23][24][25][26] Single-rotor helicopter [27][28][29][30][31] Quad copter [32][33][34][35][36] Hexa copter [30,[37][38][39][40] Octo copter [41][42][43][44][45] (a) (b) (c) (d) (e) Current RPAs applications for precision agriculture are mainly developed for small-to mediumsized crops, using rotary-wing RPASs with small range and endurance operation, leaving aside largesized crops, but farmers with a lot of hectares of land find it difficult to reach each corner of field for inspection each time. The fixed-wing RPAS does this task without any hiccup, as farmers can do regular air monitoring of fields to know the status of their crops at regular intervals of time.…”