冬小麦田植保无人飞机喷施除草剂雾滴粒径及沉积飘移分布特性评估

Evaluation of Droplet Size and Drift Distribution of Herbicide Sprayed by Plant Protection Unmanned Aerial Vehicle in Winter Wheat Field

随着植保无人飞机作业面积的增加,雾滴飘移风险也日益凸显,尤其以除草剂飘移风险危害最高。为明确除草剂溶液对雾滴粒径的影响及植保无人飞机喷施除草剂雾滴沉积飘移分布特性,本研究通过室内雾化室测定了植保无人飞机安装的离心转盘雾化喷头喷洒清水及常用的15种麦田除草剂溶液的雾滴粒径分布,并通过田间试验在药箱中添加荧光示踪剂(60 g/hm^(2))测定喷施作业区和飘移区的雾滴沉积量分布。室内测定结果表明,与清水相比,除草剂溶液对雾滴粒径影响显著。除唑草酮水分散粒剂外,其余溶液经离心转盘雾化喷头喷洒后,雾滴体积中径较清水均有所降低,且最大降低22.0%;小雾滴(V<150μm)比例均有所增加,最大增加50.8%。田间飘移试验表明,植保无人飞机喷洒150μm雾滴,在环境侧风风速为3.76 m/s时,作业区的雾滴沉积覆盖度和雾滴沉积密度仅为风速0.74 m/s时的41.3%和42.2%,且均匀性显著降低。在飘移区下风向12 m位置,雾滴沉积量为作业区的10%以下;下风向50 m处,雾滴沉积量低于检测限(0.0002μL/cm^(2))。飘移比率随风速的增加而增加,当风速达到3.76 m/s时,雾滴飘移比率达到46.4%。不同侧风风速下,90%的累积飘移位置在4.8~22.4 m。对飘移区沉积量与飘移距离、侧风风速拟合,结果表明下风向沉积量与风速呈正比。本研究为植保无人飞机冬麦田不同风速作业下的雾滴飘移距离提供数据支持,为喷雾飘移缓冲带、飘移风险评估提供依据。

With the continuous increase of the spraying area,the problem of droplet drift risk in the spraying process of UAV is becoming increasingly prominent,especially the herbicide drift.In order to clarify the effect of the herbicide solution on the droplet size and the deposition and drift distribution characteristics sprayed by UAVs,the droplet sizes of 15 herbicide solutions sprayed by the centrifugal rotary atomizer nozzle installed in the plant protection UAV were measured in the laboratory,and the distribution of droplet deposition and drift in the spraying area and drift area were measured by adding a fluorescent tracer(60 g/hm^(2))to the tank in the field.The results showed that the herbicide solution had a significant effect on the droplet size dis‐tribution.The DV50 of all the other solutions was reduced after sprayed by the centrifugal atomizer except the Carfentrazone-eth‐yl water dispersible granule,and the maximum decrease ratio was 22.0%.The proportion of small droplets(V<150μm)in‐creased,with the maximum value of 50.8%.When the environmental crosswind speed was 3.76 m/s,the coverage and number of droplets in the spraying area were only 41.3%and 42.2%of that at 0.74 m/s,and the deposition uniformity was significantly reduced.In the drift zone,the deposition amount of droplets was under 10%of in-swath zone at the downwind of 12 m,and the deposition of all the treatments at 50 m was lower than detection limits(0.0002μL/cm^(2)).The drift ratio increased with the wind speed increased.When the crosswind speed reached 3.76 m/s,the drift ratio of droplets was 46.4%.Under different crosswind,90%of the total measured spray drift were 4.8‒22.4 m.By fitting the deposition in the drift zone with drift distance and cross‐wind speed,the downwind deposition was proportional to the crosswind speed.This study provides data support for droplet drift distance of plant protection UAV spraying in wheat fields at different wind speeds in winter and provides a basis for spray drift buffer zone,drift risk assessment,and relevant standard formulation.