Abstract:
This research is aimed at the application of the geostatistical method to apparent electrical conductivity (ECa) in Banphai district, Khonkean province. ECa was measured by an EM34 instrument at the depth of 0-7.5, 0-15 and 0-30 meters. Secondary ECa data of 1,000 x 1,000 meter grid from 194 sites was obtained from The Land Development Department. Primary ECa data from an 80 x 80 meter grid was taken from 169 sites. The results show that the both ECa data can be processed by the geostatistical method. The variogram of 80 x 80 meters from all three depths fits well into the exponential model at the range of 400 750 meters while the variogram of 1,000 x
1,000 meters from all 3 depths fits into the spherical model at the range of 4,300 5,100 meters. The difference of sill from the variogram of 1,000 x 1,000 meters in each direction shows an anisotropic condition. The sill from the variogram of 1,000 x 1,000 meters from all 3 depths has the maximum value at the northwestern southeastern direction. This conforms with the pattern of elevation change that inclines from northwestern to southeastern direction. Salt-effected soil map from kriging estimation of all three depths shows that the majority of the area has a slight salt effect (ECa 80-120 mS/m). Areas of strongly and very strongly salt-effected soil are located mostly in the lower area while those having slightly salt-effected soil are located in the upper area"