A method of determining the salinity of an area of soil includes providing signal data from a radar scan of the area of soil. Improved vegetation correction is applied to the signal data using a Cloude decomposition method or a "xhv" method. In some circumstances existing vegetation correction methods are used and a synergistically improved corrected obtained. The corrected data is then inverted to determine the magnitude of the dielectric values. Salinity levels are calculated from each of the imaginary component of dielectric values.