Soil Conductivity
The primary man-made cause of salinization is irrigation. River water used in irrigation contains salts, which remain behind in the soil after the water has evaporated. The primary method of controlling soil salinity is to permit 10-20% of the irrigation water to be drained and discharged. The salt concentration of the drainage water is normally 5 to 10 times higher than that of the irrigation water, thus salt export matches salt import and salt will not accumulate.