The sphere is imposed around the homogeneous soil sample to evaluate an precise electrical resistivity of the sample. The time variation and the difference in electrical resistivity are under 0.5% when measured in the same soil sample via the cells with unique distances concerning electrodes. The measurements in 4-electrode laboratory https://powerfullyrics33322.ampblogs.com/5-easy-facts-about-soil-resistivity-testing-laboratories-bd-described-70057148