密植矮化茶园地面低容量仿形喷雾液滴沉积性能研究

Droplet Deposition Performance of Low-capacity Profiling Spray in Densely Planted Dwarf Tea Plantation

为探究地面低容量仿形喷雾技术在茶园植保作业中的适应性,以自主设计的茶园低容量仿形喷雾轨道式测试系统为喷雾载体,通过正交试验方法对茶园地面低容量喷雾的雾滴沉积性能进行了试验研究。阐述分析了喷雾测试系统的结构及控制电路,依据解析法确定了喷头安装参数;以雾滴沉积密度、沉积均匀性为主要喷雾指标,探究了喷雾高度、喷施方向、风扇转速、喷头类型和冠层梯度对茶树低容量喷雾时液滴沉积的影响。田间试验结果表明:茶树冠层梯度对雾滴沉积密度有显著性影响,其雾滴数量在冠层上、中、下部依次减少,冠层上部雾滴个数明显多于中、下部,中、下部雾滴数量没有显著性差异;喷雾高度与雾滴沉积数量呈负相关,且喷雾高度30 cm时的雾滴个数明显多于50 cm时的雾滴数量,而40 cm高度与30、50 cm时的雾滴数量无显著性差异。喷施方向、冠层梯度对雾滴分布均匀性有显著性影响,喷施方向45°时,其变异系数均值为0.610,显著大于0°、15°、30°时的变异系数,雾滴分布均匀性最差,而0°、15°、30°时变异系数无显著性差异;不同冠层梯度上的雾滴分布均匀性差异显著,其中冠层上部雾滴分布最均匀,而冠层中部雾滴分布均匀性最差。与常规喷雾相比,低容量喷雾的雾滴沉积量整体偏小;冠层梯度对雾滴沉积量有显著性影响,其中冠层上部沉积量均值为0.608μL/cm^2,显著大于中、下部沉积量,而中、下部雾滴沉积量差异不显著;喷施方向0°时,其雾滴沉积量均值最大,显著大于沉积量最小的45°方向。茶树低容量喷雾时,雾滴平均沉积密度均大于26个/cm2,冠层顶部变异系数均不大于标准中规定的0.5,满足国家标准中农药喷雾机喷洒质量要求。

In order to explore the adaptability of ground low-capacity profiling spray technology in tea plantation operation, a tea garden low-capacity contour spray orbit test system was designed, which was used as a spray carrier. The experimental study on the droplet deposition performance of low-volume spray on tea garden ground was carried out by orthogonal test method. The structure and control circuit of the spray test system were analyzed. The nozzle installation parameters were determined according to the analytical method. The droplet deposition density and deposition uniformity were taken as the main spray indicators, and the effects of spray height, spray direction, fan speed, nozzle type and canopy gradient on droplet deposition during low-volume spray of tea tree were investigated. The field experiment results showed that the tea tree canopy gradient had a significant effect on the droplet deposition density, and the number of droplets was decreased from the upper, middle and lower layers of the canopy. The number of droplets in the upper part of the canopy was significantly higher than that in the middle and lower parts, while there was no significant difference in the number of droplets in the middle and lower parts. The spray height was negatively correlated with the number of droplets deposited, and the number of droplets at 30 cm was significantly greater than that at 50 cm, while there was no significant difference in the number of droplets at 40 cm and 30 cm and 50 cm. The spray direction and the canopy gradient had a significant effect on the uniformity of droplet distribution. When the spraying direction was 45°, the coefficient of variation was 0.610, which was significantly greater than the coefficient of variation of 0°, 15°, and 30°, and the uniformity of droplet distribution was the worst. The variation coefficients of 0°, 15° and 30° were not significant. The uniformity of droplet distribution on different canopy gradients was significant. The distribution of droplets in the upper part of the canopy was the most uniform, and the distribution of droplets in the middle of the canopy was the worst. The amount of droplet deposition of the low volume spray was generally small compared with that of conventional sprays. The canopy gradient had a significant effect on the amount of droplet deposition. The average sedimentation volume in the upper canopy was 0.608 μL/cm 2 , which was significantly larger than that in the middle and lower parts, while the difference in droplet deposition between the middle and lower parts was not significant. When the spraying direction was 0°, the mean value of the droplet deposition was the largest, which was significantly larger than that of the 45° direction with the smallest deposition amount. When the tea tree was sprayed at low volume, the average deposition density of each layer of droplets was greater than 26 droplets/cm 2 , and the coefficient of variation at the top of the canopy was not more than 0.5, which met the requirements of the spraying quality of pesticide sprayers in national standards. The research result provided new methods and new ideas for the reduction of pesticide application in tea tree pest control.