Development of drift reduction technology for field boom sprayers

本研究旨在对喷雾作业进行研究，通过风洞实验分析喷雾漂移机理，开发田间吊杆式喷雾器喷雾漂移减量化技术。每年5月至8月，竹内县的农民都在忙着进行病虫害防治作业。他们通常在清晨和傍晚风速较低的时候进行手术。规模化农户在使用高效喷雾器、拖车和自行式喷雾器方面较为先进，喷雾宽度在20米或更宽。风是扰乱使用化学品控制病虫害的时机的因素之一。因此，农民希望使用即使在微风到强风条件下仍可操作的漂移喷雾减少技术。随着喷雾颗粒的减小，漂移距离的对数呈线性增加。随着喷雾粒子的排放速度变慢，它也会增加。对于常规喷嘴，当使用高度为40 cm、风速为1m/S时，漂移呈指数级增加，而采用无飘移喷嘴时，漂移减小。不到传统喷嘴的一半。在无风条件下，喷雾分布模式向喷嘴方向延伸。当有风时，背风面的漂移增加，在长臂喷雾器中，需要使用自动控制装置来保持应用高度恒定。臂架高度控制器和选用的无漂移喷嘴的使用使传统喷雾器的喷雾漂移减少了近70%。这项技术使得在风速高达2.8m/S的条件下进行喷洒成为可能。因此，该技术在减少喷洒操作中的漂移方面非常有效。

This research was conducted to investigate spray operations, to analyze the spray drift mechanism by wind tunnel experiments, and to develop the spray drift reduction technology for field boom sprayers.1. From May to August every year, farmers in Tokachi are busy doing pest control operations. They usually do the operation in the early morning and evening when the wind velocity is low. Large-scale farmers are more advanced in the use of high-efficiency sprayers, the trailer and self-propelled types , with application width of 20 m or more. The wind is one of the factors that disturb the timing of the application of chemicals to control pests and diseases. Therefore, farmers desire to use drift spray reduction technology that can still be operated even in mild to strong wind conditions.2. The logarithm of the drift distance linearly increases, as the spray particles become smaller. It also increases, as the discharge velocity of the spray particles becomes slower. For conventional nozzles, the drift increases exponentially beginning at the application height of 40 cm and wind velocity of 1 m/s. However, when driftless nozzles were used, the drift was reduced. to less than half to that of the conventional nozzles. At no wind condition, the spray distribution pattern extends to the direction of the nozzle. When there is a wind, the drift in the leeward side increases, in sprayers with long boom, the use of automatic control device is necessary to keep the application height constant.3. The use of the boom height controller and the selected driftless nozzle decreased the spray drift of the conventional sprayers by almost 70%. This technology made it possible to spray at wind velocity condition of up to 2.8 m/s. Therefore, the technology is extremely effective in reducing the drift in spraying operations.