Welcome to the forum, and thanks for using code tags on your first post.
Please post links to the sensor that you bought, to the serial communications adapter you are using and a photo of your wiring.
Does the sensor and serial adapter actually work? Post the values that this statement prints.
Serial.print(values[i], HEX);
Are you aware that "soil salinity" and EC values are simply related by a constant multiplier (determined by the actual ions present in the sample)?