Here's the answer

April 29, 2020   photos  

Charcoal absorbs moisture n salts helps in good conductivity in presence of moisture. To maintain the resistance of Earth below or equal to 1 OHM. In general, this is not a proper way to install grounding. Copper plates should be used instead. Finally, without you use any of them is not important. It's important to have a good deep on the ground. We can say that it is mainly a ritual practice to be able effectively to provide the least resistance path in the earth.