This video describes a simple soil sampling procedure for sampling soil at different depths, down to 45 cm.
Tools Needed:
A) 24" long, 13/16" diameter, carbide-tipped ship-auger bit (search: "ITM CPP-27132 13/16" Diameter by 24" Power Pole"
B) 1" internal threaded through-the-3wall straight connector (
https://www.mcmaster.com/3736k3 )
C) Standard ~2 gallon plastic bucket
D) Battery powered drill