喷雾方式对农药雾滴在水稻群体内沉积分布的影响

【目的】分析喷雾方式对农药雾滴在水稻群体内沉积分布的影响，研究提出稻田合理的喷雾方式，提高稻田农药利用率。【方法】在水稻分蘖期、孕穗期和扬花期，用配有空心圆锥雾喷头的手动喷雾器叶面喷洒和配有气力式弥雾喷头的弥雾机下倾45°角喷洒指示剂丽春红-G溶液，收集并测定沉积在植株上层、中层和下层不同点位载玻片上的雾滴指示剂丽春红-G沉积量。【结果】以不同喷雾方式施药，水稻叶片正面、背面及垂直方向不同点位的丽春红-G沉积量有显著差异。在水稻分蘖期、孕穗期、扬花期用手动喷雾器叶面喷雾和弥雾机45°角下倾喷雾，丽春红-G的沉积量在水稻群体空间内的分布趋势均表现为上层＞中层＞下层。在水稻分蘖期用手动喷雾器叶面喷雾，13.3%玻片上丽春红-G的沉积量接近于平均数；52.9%玻片上丽春红-G沉积量低于平均数；33.75%玻片上丽春红-G的沉积量高于平均数。在水稻分蘖期用弥雾机45°角下倾喷雾，20.4%玻片上丽春红-G的沉积量接近于平均数；45.4%玻片上丽春红-G沉积量低于平均数；34.2%玻片上丽春红-G沉积量高于平均数。在水稻孕穗期和扬花期用手动喷雾器叶面喷雾，分别有33.3%和28.1%的玻片上没有丽春红-G的沉积；而用弥雾机45°角下倾喷雾，没有丽春红-G沉积的玻片比例分别为13.9%和5.0%。在水稻孕穗期用手动喷雾器和弥雾机喷雾，分别只有6.4%和11.7%玻片上的沉积量接近于平均值，而在扬花期时该比例分别为7.2%和17.2%。在水稻分蘖期、孕穗期和扬花期用手动喷雾器叶面喷雾，喷雾雾滴主要沉积在表示叶片正面的载玻片上，其沉积量占总沉积量的66.3%、85.1%和84.9%，其中在植株上层表示叶片正面载玻片上的沉积量占总沉积量的38.7%、42.2%和45.6%，在表示叶片背面和垂直面玻片上的沉积量很少。弥雾机下倾45°角喷雾，在表示叶片背面和垂直面玻片上的沉积量多于手动喷雾器叶面喷雾，但在表示叶片正面玻片上的沉积量仍占总沉积量的50.5%、50.6%和53.1%，其中植株上层表示叶片正面玻片上的沉积量占总沉积量的32.9%、27.9%和31.5%。【结论】如果以单位面积载玻片上的平均沉积量作为防治病虫害的有效剂量，那么在水稻群体内同时存在剂量浪费与剂量不足的现象。手动喷雾器压顶喷雾，喷雾雾滴主要沉积在植株上层叶片正面，沉积量占到总沉积量的1/3以上，而在叶片背面和茎秆上的沉积量很少，尤其是在植株基部叶片和茎秆上，沉积量趋向于零。采用弥雾机下倾45°角喷雾，喷雾雾滴在植株上层叶片正面的沉积量仍超过总沉积量的1/4，但在施药量低于手动喷雾器压顶喷雾条件下，各层叶片背面和茎秆上的沉积量都显著高于手动喷雾器叶面喷雾，说明弥雾机下倾45°喷洒，农药雾滴能够进入植株中下层，在叶片背面及茎秆上沉积。

Influence of Spray Method on the Deposit and Distribution of Spray Droplets in Rice Field

【Objective】The objective of this study is to analyze the influence of spray method on the deposit and distribution of pesticide within the rice population, and to put forward reasonable spay technology and improve the utilization ratio of pesticide in rice field. 【Method】The solution of ponceau-G was sprayed by manual sprayer with a hollow cone nozzle upon rice plant and mist sprayer with pneumatic nozzle down 45° tilt angle at rice tillering, booting and flowering stages. The ponceau-G deposited on the microslides, which respectively showed the obverse and reverse of rice leaves and the vertical stem of plant, were collected and measured.【Result】There was a significant difference among the deposition amounts of penceau-G sprayed by different methods at different sites within the field rice population at different growing stages. The deposit rate of ponceau-G was manifested with a distribution trend of upper layer＞middle layer＞lower layer. At the rice tillering stage, manual sprayer was applied and the deposition of ponceau-G on 13.3% of microslides was close to the average value, the deposition of ponceau-G 52.9% of microslides was lower than the average value, and 33.75% was higher than the average value. At the rice tillering stage, mist sprayer with pneumatic nozzle down 45° tilt angle was applied and the deposit rate of ponceau-G on 20.4% of microslides was close to the average value, 45.4% was lower than the average value, and 34.2% was higher than the average value. At the booting and flowering stages, manual sprayer was applied and 33.3% and 28.1% of microslides did not have any deposition of ponceau-G. When mist sprayer with pneumatic nozzle down 45° tilt angle was applied, there was 13.9% and 5.0% of microslides did not have any ponceau-G deposition. The deposition of only 6.4% and 11.7% of microslides was close to the average value at booting stage for manual sprayer and mist sprayer. At the flowering stage, the proportion was 7.2% and 17.2%, respectively. For manual sprayer, ponceau-G mainly deposited on the microslides expressing obverse of leaves and the amounts were, respectively, 66.3%, 85.1% and 84. 9% of total deposits on microslides in three rice stages, among which the amount of ponceau-G on the microslides from upper layer of plant were, respectively, 38.7%, 42.2% and 45.6% of total deposition. There were litter deposition on the microslides expressing the reverse of rice leaves and the vertical stem of plant, especially on some microslides put in the base of rice plant, the amount of ponceau-G was zero at rice booting and flowering stages. For mist sprayer, the deposition on the microslides showed the reverse of rice leaves and the vertical stem of plant was more than that of manual sprayer. However, the ponceau-G on the microslides showing obverse of leaves were still 50.5%, 50.6% and 53.1% of total deposits, among which the ponceau-G on the microslides from upper layer of plant was, respectively, 32.3%, 27.9% and 31.5% of total deposition.【Conclusion】If the average of total deposition on each microslides was the pesticide dose controlling pest effectively, there were shortage and waste of dose within rice population at the same time. The fog drip of manual sprayer spraying mainly deposited on the obverse of rice leaves of plants’ upper leaves. The deposition rate accounts for above 1/3 of the total deposition amount, while the deposition rate was few on the reverse of leaves and the vertical stem, especially on the plants’ base leaves and vertical stem, on which the deposition rate was nearly zero. When mist sprayer with pneumatic nozzle down 45° tilt angle was applied, the deposition rate of fog drip on the obverse of rice leaves of plants’ upper leaves was more than 1/4 of the total deposition amount. However, when the application volume was less than that of manual sprayer conducting coping spraying, each layer of the reverse of leaves and the vertical stem was demonstrated a significantly higher deposition rate than manual sprayer. It illustrates that spraying with the mist sprayer with pneumatic nozzle down 45° tilt angle, pesticide droplets could be delivered to middle and lower layer and deposited on rice stem and reverse side of leaves.