农药液滴在水稻叶面的动态润湿铺展行为  

The Dynamic Wetting and Spreading Behavior of Pesticide Droplet on Rice Leaf Surface

作　　者：张建桃[1,2,3] 黄路生 刘广彬 兰玉彬 文晟 ZHANG JianTao;HUANG LuSheng;LIU GuangBin;LAN YuBin;WEN Sheng(College of Mathematics and Informatics,South China Agricultural University,Guangzhou 510642;Key Laboratory of Smart Agricultural Technology in Tropical South China,Ministry of Agriculture and Rural Affairs,Guangzhou 510642;National Center for International Collaboration Research on Precision Agricultural Aviation Pesticides Spraying Technology,Guangzhou 510642;College of Engineering,South China Agricultural University,Guangzhou 510642)

机构地区：[1]华南农业大学数学与信息学院,广州510642 [2]农业农村部华南热带智慧农业技术重点实验室,广州510642 [3]国家精准农业航空施药技术国际联合研究中心,广州510642 [4]华南农业大学工程学院,广州510642

出　　处：《中国农业科学》2024年第13期2583-2598,共16页Scientia Agricultura Sinica

基　　金：广州市科技计划项目重点研发计划(2023B03J1362);国家自然科学基金面上项目(32271985);广东省普通高校特色创新类项目(2019KZDZX1002);广东省自然科学基金(2022A1515011008);高等学校学科创新引智计划(D18019)。

摘　　要：【目的】探究表面张力、液滴粒径和叶片倾角对农药液滴在水稻叶片近轴面、远轴面动态润湿铺展行为的影响,为通过调控农药液滴在水稻叶面的动态润湿铺展行为实现水稻施药的“减施增效”提供依据。【方法】通过调节Silwet-408的浓度配制出表面张力为21.4、33.2、43.7 mN·m^(-1)的Silwet-408溶液代替农药药液,利用液滴发生器生成532、627、746、830、957μm的单液滴,对其在倾角为40°、65°、85°水稻叶片近轴面、远轴面的动态润湿铺展行为进行全因子试验。【结果】表面张力、液滴粒径、叶片倾角均显著影响(P<0.05)水稻叶面的液滴接触角变化率,且近轴面、远轴面所受影响的整体趋势基本相同,增大叶片倾角或减小液滴粒径或降低表面张力均能增大接触角变化率,促进液滴润湿铺展。其中,以降低表面张力的效果最显著,当表面张力从33.2 mN·m^(-1)降至与水稻叶面临界表面张力接近的21.4 mN·m^(-1)时,叶片近轴面的接触角(前进角和后退角)变化率分别增大7.49、6.22倍,远轴面的分别增大11.13、7.61倍,液滴的润湿性在75 s内从较差或差(80°≤接触角<100°或接触角≥100°)转变成中等或好(60°≤接触角<80°或接触角<60°);当表面张力比水稻叶面临界表面张力大得多时,接触角变化率随叶片倾角的增大而增大,随液滴粒径的减小而增大,但叶片倾角的影响小于液滴粒径的影响,经过75 s后,几乎所有粒径的液滴仍保持较差或差的润湿性(80°≤接触角<100°或接触角≥100°)。液滴润湿滞后现象分析表明,水稻叶面的粗糙度相对较小,液滴润湿滞后现象并不严重。表面张力与水稻叶面临界表面张力接近的液滴在固-液-气三相体系动态表面张力的驱使下在叶面润湿铺展,接触角随时间的动态变化可使用模型θ=θe+Aexp(-Kt)进行拟合;表面张力比水稻叶面临界表面张力大得多的液滴虽能稳定地黏附在【Objective】The objective of this study is to investigate the effects of surface tension,droplet size,and leaf angle on the dynamic wetting and spreading behavior of pesticide droplets on both adaxial and abaxial surfaces of rice leaf,and to provide a basis for realizing the“reduce application and increase efficiency”of rice spraying by regulating the dynamic wetting and spreading behavior of pesticide droplets on the rice leaf surface.【Method】A full factorial experiment was designed to investigate the dynamic wetting and spreading behavior of single droplet on both adaxial and abaxial surfaces of rice leaf in this study.The Silwet-408 solutions with surface tension of 21.4,33.2,and 43.7 mN·m^(-1)were formulated by adjusting the concentration of Silwet-408 to replace the pesticide solutions.A droplet generator was used to produce the single droplets of 532,627,746,830,and 957μm.The leaf angles were set as 40°,65°,and 85°.【Result】There were significant effects of surface tension,droplet size,and leaf angle on the rate of change of droplet contact angle on the rice leaf surface(P<0.05),and the overall trend of the influences on the adaxial and abaxial surfaces was basically the same;increasing leaf angle or reducing droplet size or lowering surface tension could increase the rate of change of contact angle and promote the wetting and spreading of droplet.Among them,the effect of lowering surface tension was the most significant.When the surface tension was decreased from 33.2 to 21.4 mN·m^(-1),which was close to the critical surface tension of rice leaf surface,the rate of change of the contact angle(advancing contact angle and receding contact angle)increased by 7.49 and 6.22 times for the adaxial surface,and 11.13 and 7.61 times for the abaxial surface,and the wettability of the droplets was changed from relatively poor or poor(80°≤contact angle<100°or contact angle≥100°)to medium or positive(60°≤contact angle<80°or contact angle<60°)within 75 s;when the surface tension was much l

关 键 词：农药液滴 水稻叶面 动态润湿铺展 接触角 润湿滞后 表面张力 

分 类 号：S435.11[农业科学—农业昆虫与害虫防治]