That was an old test I made years ago.
I used a 20m long roll of insulated copper wire. About 16m are buried under the lawn, between trees, the remaining 4m are used as a buried line to the foot of another tree. There, the two ends of the loop are connected to 20m of 75 ohm coax line, 2m buried, then remaining up to my listening shack. No balun, no transformer, no accessories anywhere along.
NO GOOD RESULTS !
But on that particular band, I have very strong noise from the neighbourhood, PLC type, with all my other antennas. And with that buried loop, on 3265, quite less of that PLC pest. Nothing more.
BTW, I remember that wires on the ground, as they slowly become wire under the lawn are also losing their efficiency to collect waves.
EDIT : I choose to bury the wire, not to leave it above the grass (a danger when walking, a hasstle to mow the lawn)