Development of a Portable Soil EC Measuring System

Abstract. Agrology research indicates that soil electrical conductivity (EC) is an important soil parameter. It can reflect the influence of exterior environment to soil, such as temperature, salinity and humidity. Furthermore, through the acquisition of EC, it could provide crop information, crop yields and expected analysis in detail. Therefore, soil electrical conductivity data acquisition is significant to ensure the difference of the field spatial distributing. This paper describes a portable soil EC measuring system based on four-electrode method, which satisfies the requirement of real time measuring EC in greenhouse and field. The EC measuring device includes exterior design and control circuit design，the control circuit design includes input excitation signal circuit, output signal conditioning circuits, power conversion circuits, main control unit, A/D converter circuit, data display circuit and USB memory circuit. An AC constant current source stability test shows that the system has a stability excitation signal and an experiment of soil salt content shows that the system output has a high relativity with the salt content of soil which R² is 0.9796.