Chen Hongyu, Weng Hua, Zhu Haixia, Shen Shuo, Li Wei
Academy of Agriculture and Forestry Sciences, Qinghai University, Key Laboratory of Qinghai -Tibetan Plateau Biotechnology (Qinghai University), Scientific Observing and Experimental Station of Crop Pest in Xining, Ministry of Agriculture, Key Laboratory of Agricultural Integrated Pest Management of Qinghai Province, Xining, 810016, Qinghai Province, PR China.
Heliyon. 2024 May 9;10(9):e30935. doi: 10.1016/j.heliyon.2024.e30935. eCollection 2024 May 15.
Crop protection pesticide spraying aims to greatly improve the utilization rate of pesticides. Controlling pesticides deposition requires a thorough understanding of the spatial behaviour of spray droplets.The Qinghai-Tibet Plateau, which is the headwaters of three largest water resources (Yangtze, Yellow and Lancang) in China, has exceptionally unique climatic characteristics. The goal is to reduce the amount of pesticides entering water resources. The wind tunnel experiment was used to validate the discrete phase method for tracking the trajectories. Cooperation between the smaller and larger droplets (greater than 150 μm) in the dense area around the nozzle can undoubtedly enhance the initial dispersion of droplet sizes. Droplet coalescence, which lowers the proportion of readily dispersed droplets, can greatly boost droplet deposition onto the target location.The crucial drift height is presented and clarified when droplets gradually disperse by identifying the descending length at which efficiency of mass transit starts towards decrease off quickly. The pesticide transport efficiency will not be enhanced by reducing the initial relative spread of droplets if the actual spray height surpasses the crucial drift height, and may even worsen drift loss. The temperature and relative humidity of the air have a greater influence on the evaporation losses of droplets smaller than 150 μm. In addition to providing information about pesticide spraying, the results of studies on droplet drift behaviors also suggest a method for controlling drift.
农作物保护农药喷洒旨在大幅提高农药利用率。控制农药沉积需要深入了解喷雾液滴的空间行为。青藏高原是中国三大水资源（长江、黄河和澜沧江）的源头，具有极为独特的气候特征。目标是减少进入水资源的农药量。风洞实验用于验证跟踪轨迹的离散相方法。在喷嘴周围的密集区域，较小液滴与较大液滴（大于150μm）之间的协同作用无疑会增强液滴尺寸的初始分散。液滴聚并会降低易于分散的液滴比例，从而极大地促进液滴在目标位置的沉积。通过确定质量传输效率开始迅速下降时的下降长度，在液滴逐渐分散时给出并阐明关键漂移高度。如果实际喷雾高度超过关键漂移高度，降低液滴的初始相对扩散不会提高农药传输效率，甚至可能加剧漂移损失。空气的温度和相对湿度对小于150μm的液滴蒸发损失影响更大。除了提供有关农药喷洒的信息外，液滴漂移行为的研究结果还提出了一种控制漂移的方法。
