Patch spraying is a technological way to reduce herbicide amounts required to control weeds by triggering spraying only where weeds lie. Nevertheless, the adoption rate of this technology by farmers is still low and there is a lack of efficient tools to assess patch herbicide applications depending on spraying features and weed spatial distributions. To avoid unrealistic in-field experiments, a virtual patch sprayer is designed and computer simulations are carried out to quantify herbicide reduction possibilities and assess the ability to apply the right rate on weed patches to ensure herbicide efficiency. The spray application simulator combines the theoretical description of the sprayer using various boom section widths (from 0.5 to 24 m) with experimental data describing various nozzle spray patterns obtained from three commercial nozzles. Virtual weed infestation maps are designed using random locations of weed patches with various spatial aggregation degrees modelled by different weed coverage rates and elliptical patch sizes. Simulation results are analysed through two performance indicators: i) the herbicide reduction ratio obtained with patch spraying compared to a uniform broadcast application (on the entire field area), ii) the proportion of weed patch area on which the application rate is higher than 85% of the prescribed application rate. Computer simulations enable to estimate a simplified relationship to quantify the reduction of herbicide use as a function of the weed coverage rate, the size of weed patches and the boom section width. This demonstrates that computer simulations provide practical tools to estimate the sprayer spatial resolution required to reach a given herbicide reduction target according to the weed spatial distribution. Simulations also demonstrate that the use of narrow section widths equipped with traditional nozzles leads to a significant proportion of weed areas exposed to herbicide under-application in the case of small patches.

斑块喷洒是一种技术方法，可通过仅在杂草所在的地方触发喷雾来减少控制杂草所需的除草剂量。然而，农民对该技术的采用率仍然很低，并且缺乏有效的工具来根据喷洒特征和杂草空间分布来评估贴片除草剂的应用。为避免不切实际的野外实验，设计了虚拟补片喷雾器，并进行了计算机模拟，以量化除草剂减少的可能性，并评估对杂草补片应用正确剂量以确保除草剂效率的能力。喷涂应用模拟器结合了使用各种喷杆截面宽度（0.5至24 m）的喷涂机的理论描述以及描述从三个商用喷嘴获得的各种喷嘴喷涂方式的实验数据。虚拟杂草侵染图是使用杂草斑块的随机位置设计的，该杂草斑块具有通过不同杂草覆盖率和椭圆形斑块大小建模的各种空间聚集度。通过两个性能指标来分析模拟结果：i）与均匀播种施用相比（在整个田地上）通过贴片喷雾获得的除草剂减少率，ii）施用率高于85的杂草贴片区域的比例规定用量的百分比。计算机模拟能够估算简化的关系，以量化除草剂使用量的减少，该减少量取决于杂草覆盖率，杂草块的大小和吊杆截面宽度。这表明计算机模拟提供了实用的工具，可根据杂草的空间分布来估算达到给定的除草剂减少目标所需的喷雾器空间分辨率。模拟还表明，在传统小喷嘴的情况下，使用窄截面宽度的传统喷嘴会导致相当一部分杂草面积暴露于除草剂施用不足的情况。