Millimeter scale sensor array system for measuring the electrical conductivity distribution in soil

•We fabricate the EC sensor array system which is comprised millimeter sensor chips.•We make model soil that is constant sandy soil particle size and moisture content.•We measured the soil solution EC distribution of model soil in real time.•The model soil EC of different fertilizer concentration to be equilibration.•The EC increase due to dissolution of the solid ammonium sulfate has been confirmed.