Continuous measurement of substrate electrical conductivity in container grown plants

Saturated paste extraction is the most common method used today to determine soil electrical conductivity (EC). This results in a measurement that is not only an estimation of actual conditions, but is limited to a single point in time. An EC probe was developed by combining an EC sensor and a ceramic cup of a tensiometer. The probe is able to monitor soil EC nondestructively, continuously, and in nearly real-time. The EC probe and a tensiometer are installed in a container with a rose plant in coconut coir which is initially saturated with nutrient solution. Over a period of five days, tension increases rapidly during the day and very little during the night. EC changes very little at night. But, in the early morning, it decreases before increasing during the remainder of the day. This demonstrates that when the probe is installed with a tensiometer in a container with a plant, the data collected can show the effects of plant water and nutrient uptake on soil moisture and EC. This information can lead to further understanding of nutrient and water uptake and the effects of substrate salinity and on plant growth.