On/off patch spraying based on weed maps is used in site-specific weed management. Two prerequisites for realising patch spraying are accurate weed detection and targeting of the herbicides on weed patches. There is plenty in the literature about weed detection, but little attention has been paid to the spatial accuracy of herbicide application. This study was conducted in order to assess the extent to which patch-sprayed herbicides are targeted precisely according to pre-loaded prescription maps and to evaluate a new spatial assessment method. The new method consisted of spraying with red Ponceau 4R dye, unmanned aerial vehicle (UAV) imagery and spatial image analysis based on a geographic information system (GIS). The sprayed dye was clearly visible in aereal images and the locations of the sprayed areas were compared with the locations given by the prescription maps. Four different commercial sprayers with boom section width in the range of 0.5 to 3 m and driving speed in the range of 2.5 to 8 km h −1 were used in ten experiments. All the experiments were carried out in autumn in stubble fields. The results showed that the new method was fast and reliable. The incorrectly sprayed area outside targeted areas on prescription maps averaged 81% for three different sprayers with 3 m boom sections, and 5% for a sprayer with 0.5 m boom sections (individual spray nozzle control). The target areas not sprayed within the planned weed patch areas averaged 6% of the pre-defined patch area for sprayers with 3 m boom sections, and 14% for the sprayer with 0.5 m boom sections. This study revealed that the sprayer with 0.5 m boom sections had a controller that was not quick enough at opening and closing spray nozzles at normal driving speeds. Log files from the sprayer console overestimated the sprayed area by 24% and were less accurate than the spatial analysis of the sprayed areas.

中文翻译：

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一种估计除草剂计划喷洒和实际喷洒之间空间相关性的新方法

基于杂草图的开/关补丁喷洒用于特定地点的杂草管理。实现贴片喷洒的两个先决条件是准确的杂草检测和针对杂草贴片上的除草剂。有大量关于杂草检测的文献，但很少关注除草剂施用的空间准确性。进行这项研究是为了根据预先加载的处方图评估贴片喷洒除草剂的精确目标范围，并评估一种新的空间评估方法。新方法包括喷洒红色 Ponceau 4R 染料、无人机 (UAV) 图像和基于地理信息系统 (GIS) 的空间图像分析。喷洒的染料在航空图像中清晰可见，并将喷洒区域的位置与处方图给出的位置进行比较。在十个实验中使用了四种不同的商业喷雾器，其喷杆截面宽度在 0.5 到 3 m 的范围内，行驶速度在 2.5 到 8 km h -1 的范围内。所有试验均于秋季在留茬地进行。结果表明，新方法快速可靠。处方图上目标区域外的错误喷洒面积对于三台具有 3 m 喷杆截面的不同喷雾器平均为 81%，对于具有 0.5 m 喷杆截面的喷雾器（单独喷嘴控制）为 5%。在计划的杂草补丁区域内未喷洒的目标区域平均为 3 m 喷杆截面的喷雾机预定义补丁面积的 6%，0.0 米喷雾机的 14%。5 m 吊臂部分。这项研究表明，喷杆截面长度为 0.5 m 的喷雾机的控制器在正常行驶速度下打开和关闭喷嘴的速度不够快。来自喷涂机控制台的日志文件将喷涂区域高估了 24%，并且不如喷涂区域的空间分析准确。