Study of Some Factors Affecting the Measurement of Electrical Conductivity of Soils with a Four Electrode Probe

In an effort to use four electrode probe to measure soil salinity in situ and to interpret electrolytic conductivity of saturation extract (ECe) of four different textured soils it was noted that the electrical conductivity measured by four electrode probe (EC₄EP) and the electrolytic conductivity measured on saturation extract were linearly related with a high coefficient of correlation (0.984–0.998). But when the data from all the treatments (soil type and salt) were pooled, the value of correlation coefficient was lowered to 0.872. The value of linear regression coefficient were lower for C_a²⁺ and fine textured soils, but reverse was true for Na⁺ and coarse textured soil, which indicated a need of recalibration of the relation between EC₄EP and ECe, whenever the soil under investigation departs markedly in texture or the type of cation present in it.