EC Measurement and Soil Nutrients

SoilQuality measures the Electrical Conductivity (EC) of soil.

On moist soil, at a given temperature, the EC of soil is relative to the amount of nutrients in the soil: an increase of the nutrient produces an increase in Soil Electrical Conductivity.

To capture nutrients in the soil, a plant needs water so minerals can be dissolved in water and be available as nutrients to the plant. In dry soil a plant will not be able to grow and capture any nutrients. Soil EC is also affected by the soil moisture: when the soil is dry, the EC greatly drops even if there’s minerals in the soil. Therefore, the Soil EC gives a good relative indication of the available nutrients to the plant.

Temperature is also a factor that will affect the soil’s EC level. Most EC agricultural standards are given at 25°C. The higher the temperature the higher the EC. As a rule of thumb, the EC of water increases by 2 to 3% for each increase of 1°C.

Comparison of Nutrient level in time or between different soil samples should be done based on the same moisture level and temperature.

When mixing a soil with a water solution, it is important to note that the resulting EC of the soil will be according to the EC level of the water solution combined with the mineral level of the soil and the moisture level of the mix of both.