The efficiency of the root capacitance method is still judged contradictorily. It was, therefore, aimed to verify that the electrical capacitance (C_R) and impedance (Z_R) measured between ground electrode (pushed into the soil) and plant electrode (clamped on the stem) really represented the root system present in the soil. An ‘electrode separation experiment’ and a ‘root excision experiment’ were performed on potted maize plants cultivated in arenosol. The partial electrical separation of the ground electrode (restriction of the current flow in the topsoil) caused no significant changes in the capacitance and impedance of either the soil or the plant–soil system. This suggested that the current flows through a multitude of soil solution pathways, not predominantly on the wet soil surface. The progressive excision of the main root branches caused a gradual decrease in C_R (31–39% of the initial value) and an increase in Z_R (4.4- to 5.2-fold that of intact plants). C_R showed a much stronger correlation with root dry mass (R² = 0.807) than with stem cross-sectional area (R² = 0.424) in intact plants. The closeness of the latter relationship decreased further (R² = 0.377) after whole root excision. The results clearly demonstrated that the root system dominated the measured capacitance and impedance, though the role of the stem base was not negligible. In conclusion, the capacitance method is worth considering in future studies as an adequate non-intrusive approach to evaluate root size in the soil.

根电容法的效率仍被认为是矛盾的。因此，目的是验证电容（C _R）和阻抗（Z _R）在接地电极（推入土壤）和植物电极（夹在茎上）之间测量，实际上代表了土壤中存在的根系。对在槟榔中栽培的盆栽玉米进行了“电极分离实验”和“根切除实验”。接地电极的部分电气隔离（限制了表层土壤中的电流流动）不会导致土壤或植物-土壤系统的电容和阻抗发生明显变化。这表明电流流经大量的土壤溶液路径，而不是主要在湿润的土壤表面上流动。主根分支的逐渐切除导致C _R逐渐降低（初始值的31–39％）和Z _R升高（是完整植物的4.4到5.2倍）。 在完整植物中，C _R与根干重（R ²  = 0.807）的相关性比与茎截面积（R ² = 0.424）的相关性强得多。 完全根切除后，后者关系的紧密度进一步降低（R ² = 0.377）。结果清楚地表明，尽管茎基的作用不可忽略，但根系主导了所测得的电容和阻抗。总之，电容法值得在将来的研究中作为评估土壤根系大小的适当非侵入性方法。