Abstract: In view of the poor wettability of rice leaf surface,easy falling of sprayed drug droplets from the leaf surface(secondary leaf) and low utilization rate of drug solution,the influence of droplet charging characteristics on the contact angle of rice leaf surface was studied.The effects of charged voltage,charge polarity,electrode ring material,inner diameter of electrode ring and NaCl content on the surface contact angle of rice leaves were studied by experiment. Results showed that,with the increase of the charged voltage,the contact angle of the droplets on the surface of rice leaves decreased first and then increased totally.The contact angle reached the minimum value when the charged voltage was±4 kV.The positive and negative charge electrode had a significant effect on the surface contact angle of rice leaves,in general,the contact angle of the droplet with the surface of the rice leaf was small when the droplet was negatively charged.Under the condition of the same material electrode ring,the contact angle of droplets on the surface of rice leaves gradually decreased with the increase of the inner diameter of electrode ring.With the increase of NaCl content,the contact angle of droplets on the surface of rice leaves decreased first and then increased,and different varieties of rice had the best NaCl content to minimize the contact angle.The results above show that,it is feasible to reduce the contact angle of droplets on the surface of rice leaves by adjusting the charge parameters of droplets,which is of great reference significance for the efficient use of pesticides.

Key words: Contact angle, Rice, Leaf, Charged droplet, Electrode ring

摘要： 针对水稻叶片表面润湿性较差，喷洒作业时的药剂液滴容易从叶片表面滚落，药液利用率低的问题，研究液滴荷电特性对水稻叶片（倒二叶）表面接触角的影响。通过试验，研究荷电电压大小、电荷极性、电极环材料、电极环内径、NaCl含量等参数对水稻叶片表面接触角的影响。结果表明，随着荷电电压的增大，液滴在水稻叶片表面接触角整体呈先减小后增大的趋势，接触角在荷电电压为±4 kV时达到最小值；荷电正负极对水稻叶片表面接触角有明显影响，总体来说,液滴带负电荷时与水稻叶片表面的接触角较小；同种材料电极环条件下，随着电极环内径增大，液滴在水稻叶片表面接触角呈逐渐减小趋势；随着NaCl含量增大，液滴在水稻叶片表面接触角呈先减小后增大的趋势，不同品种水稻存在最佳的NaCl含量使接触角达到最小值。表明，通过调整液滴的荷电参数来减小液滴在水稻叶片表面接触角是可行的，对农药的高效利用具有重要参考意义。

关键词: 接触角, 水稻, 叶片, 液滴荷电, 电极环