静电喷雾对农药飘移及沉积分布的影响

Influence of Electrostatic Spraying on Drift and Deposition Distribution

【目的】旨在揭示静电技术对喷雾雾化性能、理化性质和沉降等方面影响,为静电喷雾技术在作物病虫草害防控应用提供依据。【方法】采用激光粒度系统比较分析静电喷雾和非静电喷雾的雾滴粒径特征,采用铂金环法和座滴法分别评测静电喷雾和非静电喷雾雾滴的表面张力和其与稗草叶片的接触角,在开放式风洞中采用麦拉片、相片纸中收集不同喷雾方式的地面飘移量及靶标的沉积量,评价静电喷雾技术对飘移沉积分布和靶标沉积量的影响。【结果】在0.3 MPa喷雾压力下,比较静电喷雾和非静电喷雾的雾滴粒径特征,发现静电喷雾的体积中径D_(50)高于非静电喷雾的,雾滴直径D_(90)却低于非静电喷雾的,但差异不显著;分布跨度S显著低于非静电喷雾的,两者的ΦVol_(<150μm)差异不显著,而静电喷雾粒径分布更加均匀。比较两者的理化性质发现,静电喷雾雾滴的表面张力及其与稗草叶片在200、400和600 ms的接触角均显著低于非静电喷雾。进一步采用Depositscan分析比较相片纸上飘移沉积规律,喷雾方式对飘移沉积雾滴D_(50)的影响均达到显著水平,且非静电喷雾显著高于静电喷雾,但喷雾方式对地面飘移量和沉积量的影响均不显著;飘移距离对雾滴D_(50)、飘移量和沉积量的影响达到显著水平,飘移距离为1 m的D_(50)、飘移量和沉积量均显著高于飘移距离为3 m处理。收集靶标上的沉积量,静电喷雾沉积靶标的量显著高于非静电喷雾处理,但是两者的防飘移效果差异不显著。【结论】相对于非静电喷雾,静电喷雾能够显著降低雾滴粒径的分布跨度,增加雾滴的分布均匀性,降低雾滴直径D_(90),降低表面张力和其与稗草叶片的接触角,增加雾滴靶标沉积率,表明静电喷雾技术在防控作物病虫草害的应用上具有较大的潜力。

【Objective】The objective is to clarify the characteristics atomization performance,physical and chemical properties and deposition of droplet,and to provide the basis for the application of electro⁃static spray technology in the crop disease,insect and grass control.【Method】In this paper,a laser particle size analyzer is used to analyze and compare the droplet size between the electrostatic spray and non-electrostatic spray.The platinum ring method and the sessile drop method are used to evaluate the surface tension and its contact angle with the blade of Echinochloa crusgalli(L.)between electrostatic spray and non-electrostatic spray.Mylar and photo paper are used in the cave to collect the amount of ground drift of different spray methods to evaluate the influence of electrostatic spray technology on the distribution of droplet drift and deposition;the amount of deposit on the target is also measured.【Result】Under 0.3 MPa spray pressure,comparing the droplet characteristics between electrostatic spray and non-electrostatic spray,this study found that the volume median diameter D_(50) of electrostatic spray is higher than that of non-electrostatic spray,butits droplet diameter D_(90) is lower.The distribution span S of electrostatic spray is significantly lower than that of non-electrostatic spray.The difference ofΦVol_(<150μm) is not significant,and the particle size distribution of the electrostatic spray is more uniform.Comparing the physical and chemical properties between electrostatic spray and non-electrostatic spray,this paper found that the surface tension of electrostatic spray droplets and their contact angles with the blade of E.crusgalli(L.)at 200,400 and 600 milliseconds are significantly lower than those of non electrostatic spray.Then mylar and photo paper are adopted to compare drift deposition distribution law of electrostatic spray and non-electrostatic spray,the influence of spraying method on drift deposition droplet D_(50) hasreached a significant level,non-electrostatic spray is significantly higher than electrostatic spray,however,the difference of the amount of drift and deposition between electrostatic spray and non electrostatic spray is not significant;The influence of drift distance on the D_(50),drift and deposition has reached a significant level.D_(50),drift and deposition at a drift distance of 1 m are significantly higher than those at the drift distance of 3 m.The amount of deposition on the E.crusgalli(L.)is significantly higher than that of non-electrostatic spraying,however,the difference of anti-drift effect between electrostatic spray and non-electrostatic spray is not significant.【Conclusion】Compared with non-electrostatic spraying,electrostatic spraying can significantly reduce the distribution span of the droplet size,increase its uniformity,decrease the D_(90) of the droplet,reduce the surface tension and its contact angle with the blade of E.crusgalli(L.),and increase the target deposition rate.The results indicate that electrostatic spray technology has potential application in preventing and controlling crop diseases,pests and weeds.