Abstract
The electrical conductivity of the extract of a saturated soil (ECSAT) was defined as:
ECSAT≡EC1:χ, when χ=ερw/(1-ε)ρdwhere EC
1:χ is the electrical conductivity of the extract of a soil sample at 1:χ soil-water ratio, ε is the porosity of the soil under actual field conditions, ρ
d is the density of soil particles and ρ
w is the density of water. The EC
SAT is not equal to the traditional index, the electrical conductivity of the extract of a saturated soil-past prepared by the standard procedure(EC
e), but both these indices have almost the same physical meaning. A comparative test on EC
SAT showed that it can be measured both in the field using TDR and in the laboratory by the dilution extract(DE)method with a reasonable degree of agreement between them. Although EC
SAT and EC
e have both merits and demerits, it can be said that EC
SAT is a more practical index than EC
e is, because the former can be measured not only in the laboratory without special apparatuses such as a vacuum pump but also in the field automatically and continuously; furthermore, it can be compared at first hand to the electrical conductivity of groundwater when water and salt movements in the soil profile are analyzed.
