ESTIMATION OF SOIL SALINITY IN SOME PHYSIOGRAPHIC MAPPING UNITS OF WADI GARAWLA , MATROUH, EGYPT, USING ELECTROMAGNETIC INDUCTION (EMI)

Abstract

: The rapid increment of soil salinity in dry lands led to more maintenances for lots of practices to improve and conserve the degraded fields. The process of soil survey is time consuming and expensive, therefore, the new remote sensing techniques become important to monitoring, estimate soil salinity in quick, easy, cheap, and could be replicate any time. The electromagnetic induction (EMI) instruments used to estimate soil salinity in easy and rapid technique. But the collected EMI instrument readings measured the soil salinity as relative value depend on the instrument calibration point and the readings need to change in EC values (dS/m). The aims of this study are mapping the physiographic units of Wadi Garawla area, Matrouh, Egypt; test the spatial distribution of the calibrated Profiler EMP-400 instrument readings; and estimated EC values from calibrated instrument readings. The results of EMI readings of VDM orientation correlated with EC values assessed in the laboratory were the most suitable for estimating EC values to study the multi and simple regressions using the EMI readings. The correlation results showed that, there was an increase in the significance of the relationship between the measured soil salinity in the laboratory with the estimated EC values using calibrated instrument readings of VDM EMI measurements at 13, 14, and 15 KHz. The descriptive statistical of the produced maps showed that, using the calibrated 15 KHz readings values gave the lowest standard deviation. This confirms that, it is the most appropriate readings to estimate the soil salinity values maps.