An Evaluation of Electrical Conductivity Meters for Making in-Field Soil Salinity Measurements.

Soil electrical conductivity (EC) can be used to as a parameter to assist agricultural producers in making economically important management decisions.  Since particular crops and crop varieties respond dynamically to soil soluble salt levels in relation to crop growth stage and soil moisture content and many management decisions must be made in a short time window.  Some crop stress factors could be removed or mitigated if a dependable handheld EC meter could be implemented during the growing season. Therefore, the accuracy of four handheld EC meters for measuring soil EC was evaluated and compared to one laboratory grade EC meter across a range of environmental temperatures, soil textures (clay content), and sulfate and chloride salt mixtures under controlled laboratory conditions.  The levels at which these parameters were evaluated were as follows: room temperature of 15, 20, and 25¢ª C, soil textures of sandy loam, loam, silt loam, silty clay loam, and silty clay.  The salt solutions were composed of mixed sodium and magnesium sulfate salts and sodium and magnesium chloride salts at target values of 0, 1, 2, 4 and 8 dS/m.