How do I measure soil salinity and sodicity?
It is generally agreed upon among soil scientists that salinity of the soil saturated paste extract most closely represents conditions faced by plants. The general guideline is that the soil saturated paste extract will be equal to between 1.5 and 3 times the salinity of the applied irrigation water and generally will be less saline than what the plant is exposed to. The device used to measure salinity of water is an EC meter. With the right soil water mixtures, they can be used to measure salinity of soil as well. However, only a lab can measure the sodicity, or SAR, of irrigation water. Your local county Extension or United States Department of Agriculture, Natural Resource Conservation Service (USDA-NRCS) offices will have information on purchasing or borrowing meters, as well as information on labs in your area.
