Abstract
An electromagnetic measurement with GEM‒2 was examined as a simple and rapid method for measuring soil electrical conductivity （EC） in tsu-nami‒inundated farmlands. The apparent soil electrical conductivity （ECa） ascertained using GEM‒2 was too high according to the increase in the application rate of potassium chloride in a pseudo‒seawater inundated field of which the EC had been adjusted using potassi-um chloride spraying. Furthermore, results for ECa were correlated with those obtained using a soil EC sensor. These results showed that differences in ECa values were obtainable through nondestructive and noncontact sensing with GEM‒2 in tsunami‒inundated farmland. The overlying contour plot measured using GEM‒2 on the map, such as Google Earth, was able to easily provide more information about the relation be-tween ECa and terrain condition. Measuring ranges in the depth direction according to the GEM‒2 measure-ment at 80 kHz frequency were regarded as affecting all layers from the fi eld surface to at least 1 m below without limited to only the fi eld surface. We can com-pare EC1:5 and ECa by using the soil EC sensor to-gether with GEM‒2, thereby rapidly investigate for salt leaching while working in tsunami‒inundated farmlands.
