The root zone of plant provides a base for use of nutrients and water resources and supports the plant, in which the interaction between root and medium affects the uptake of water and nutrients. The technology of impedance spectroscopy can well reflect the dynamic change of water content and root biomass in the root zone. However, there are many factors that limit the application scenarios which can be measured. The research was focused on the problems encountered in the impedance spectroscopy measurement for the substrate root zone under the adjacent excitation strategy within the range of 100Hz~2MHz.The solutions were provided and compared. For the effect of the extended fixtures, compensation methods of single-port network and dual-port network were calculated and analyzed. The experimental results supported that the selection of single-port network compensation method was a better strategy for pure substrate impedance measurement, whose process was simple and the compensation result was remarkable. Through lengthening the electrodes, the range of water content in substrate root zone, that ensure the impedance spectroscopy can be accurately measured under natural dry condition, was increased to 11.27% at 8mm condition from 8.35% at 3mm, which was 1.35 times of the original range and effectively attenuated the effect of the root zone water content decrease on electrode coupling. And the data differences under different electrode lengths and effect of variations in electrode geometry were analyzed. The results showed that the change in electrode length had no significant impact on the overall trend of the impedance spectroscopy data. Furthermore, the reasons why the negative resistance data appeared in the high frequency range were presented and analyzed. These analysis and resolutions of measurement compensation and coupling problems would provide references for scientific researchers in the impedance study for the root zone.