Resistor which reacts to moisture in soil or water.

[Scarlet_pat]

my friend and i are doing a DP lab, we are trying to find a resister which reacts to water/ moisture in soil. a resistor that is directly proportional to the moisture in the soil

thank you.

 

[Andy Resnick]

Could the soil itself be a resistive element?

http://www.ictinternational.com.au/appnotes/ICT227.htm