菠菜叶面溴氰菊酯液滴的叠加凝并过程与施药效果

Stacking Process of Deltamethrin Droplets on Spinach Leaves Surface and Its Pesticide Application Effects

[目的]探究溴氰菊酯药液液滴在菠菜叶片表面的叠加凝并过程及其对施药效果的影响。[方法]采用光学接触角测量仪测量溴氰菊酯液滴的表面张力、液滴叠加前后动态接触角及铺展直径等润湿参数。[结果]溴氰菊酯乳油稀释400倍后药液液滴的表面张力为39.63 m N/m;当液滴高度为8 mm,液滴撞击速度为0.073 m/s时,菠菜叶面等体积(4~6μL)液滴在垂直方向叠加碰撞会出现3种行为:即单方向撞击相邻液滴凝并,中间间隙撞击相邻液滴凝并,单方向撞击相邻液滴不凝并;前2种叠加凝并成新液滴后接触角均减小,减幅在34.69%~40.5%范围内,而后者叠加凝并形成的新液滴,其接触角增大,增幅在6.47%~14.2%;当相邻液滴间距L≤0.69 mm时,液滴单方向撞击会与相邻液滴凝并,当相邻液滴间距L≥0.77 mm时,液滴单方向撞击不会与相邻液滴凝并。[结论]中间间隙撞击相邻液滴凝并行为是3种叠加凝并行为中铺展直径增幅最大的,增幅达到152.09%,其施药效果优于另外2种叠加凝并行为。

[Aims] In order to investigate the stacking process of deltamethrin reagent droplets on spinach leaves surface and its effect on pesticide application effects.[Methods] The surface tension of the deltamethrin droplets, before and after of droplet stacking dynamic contact angle, and the spreading diameter were measured by using optical contact angle measuring instrument.[Results] The surface tension of the deltamethrin reagent droplet after diluted for400 times was 39.63 m N/m. When the droplet height was 8 mm, and the droplet impact velocity was 0.073 m/s, the equal volume(4-6 μL) and vertical superposition collision droplets on spinach leaf will occur three kinds of behavior:unidirectional collision of adjacent droplets, interstitial collision of adjacent droplets, unidirectional collision of adjacent droplets and non-coagulation of adjacent droplets. The contact angle decreases in the range of 34.69-40.5% after superimposed condensation of the first two kinds of droplets, while increases in the range of 6.47-14.2% for the new droplets formed by superimposed condensation of the latter. When the distance between adjacent droplets was less than0.69 mm, one-way collision of droplets will coagulate with adjacent droplets. When the distance between adjacent droplets was more than 0.77 mm, one-way collision of droplets will not coagulate with adjacent droplets.[Conclusions] The first two superimposed coagulation behaviors make the spreading diameter of the new droplets on the spinach leaves increasing range reach 152.09%, and their pesticide application effect are obviously better than the latter.