Potential measurements between the first and second electrodes {TAIL ~ validate ion transport} between {HEAD ~ the soil} and the first reference electrode 
Potential measurements between the first and second electrodes { TAIL ~ validate ion transport } between { HEAD ~ the soil } and the first reference electrode
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH