Doesn't work that way, but I see your point, lol. The blower just pushes air, there's a feeder, usually rotary, that drops material into the air stream at the back of the box. Gravel might be too heavy to move consistently, but soils and mixes are fine.
Yup seen bark blowers (to fill a truck) drop it in downstream of the blower wheel.
But a bale shredding type goes thru.
I have worked on some machinery that I said "It looked like it was sandblasted with 2-b"
Seriously, the OP needs to do some quick math, and figure out the total amount needed down there.
A simple portable electric belt conveyor might be just the ticket (as has been mentioned before)
A one ton pick up dump with a coal door to hit the conveyor, and someone below moving the conveyor
by hand may be all that's needed.