I can't say in pounds about wieght, but this fall I had a pretty big load.
I Power raked and dethatched my parents lawn as part of renovating, because they lost a large area from drought.
I bagged the debris with my mower and it had a lot of dirt in it also.
With two or three tarps layered I had my pickup pilled high till it was spilling over the edges. and even had a tarp full on the trailer.
It all came off pretty slick but I had my brother helping me pull the tarps.
In heavy growing times I might fill the pickup bed level layering two tarps and be able to pull it off myself. The trick is to not let any one layer get too heavy to pull of yourself.
I might have some left to sweep or blow out but it sure beats scooping or raking the whole thing.
I might try to get a series of pics unloading this spring so I can explain it better.