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Electrical conductivity is an indicator for measuring soil salinity. Salinity can be a concern associated with specific soil types and with salt accrual through improper irrigation techniques.
How to operationalize the metric
Method of data collection and data needed to compute the method:
The electro conductivity of the saturated paste extract is measured to determine the level of salinity.
Dissolve 0.7456g KCl in 1000ml water: 1.412mS/cm at 2500C.
Dissolve 7.456g KCl in 1000ml water: 12.900mS/cm at 2500C
Weigh about 300g ± 25g soil into a plastic container.
Add water to the soil with string until it is nearly saturated.
Allow the mixture to stand covered for several hours to permit the soil to imbibe the water, and then add water to achieve a uniformly saturated soil-water paste. As this point, the soil-water paste glistens as it reflects light, flows slightly when the container is tipped, slides freely and cleanly off a spatula, and consolidates easily by tapping or jarring the container after a trench is formed in the paste with the side of a spatula.
After mixing, allow the sample to stand (preferably overnight, but at least four hours), and then recheck the criteria for saturation. Free water should not collect on/above the soil surface, nor should the paste stiffen markedly or lose its glisten. If the paste is too wet, add additional dry soil to the paste mixture.
Transfer to a Buchner filter funnel fitted with Whatman No. 42 filter paper. Apply vacuum, and collect the filtrate. If the initial filtrate is turbid, refilter.
Measure the conductivity of the filtrate against that of the standards.
Unit of analysis:
Limitations regarding estimating and interpreting: