What are some applications for our soil conducting electricity science experiment?

Question

We are doing an experiment on why soil conducts electricity. Our procedure is to place a 9V battery in 3 inches deep of soil and place the multimeter needles on top of the soil and see how much voltage there is. Mud gave us the most voltage with 0.2 V out of the 9V battery and dry soil gave the least (0.03V). We want to know some applications that this is useful to and to the world

Answer 1

Sounds like the moisture content was the reason why mud conducted better.  Cows standing under a tree in a thunder storm have been killed in 4 directions from the tree. Has anything been done to test electrical stimulation to  root growth, it increases bone growth.