A system for measuring soil properties on-the-go uses soil-engaging components of an existing farm implement as electrodes for a soil conductivity measurement system. The soil-engaging components can be: electrically isolated shanks and/or replaceable points or sweeps on a tillage implement; a row cleaner or coulter device on the front of a planter row unit, the closing wheels on the back of the planter row unit, or an entire planter row unit; or an additional soil contacting component added to an existing implement shank. A soil engaging component serving as an electrode is electrically isolated from other components of the implement. A soil conductivity measurement is made by passing current between a first pair of soil-engaging electrodes and measuring voltage resulting from the current between a second pair of soil-engaging electrodes. A narrow profile sensor unit can be attached to the implement to measure additional soil properties.