I've recently moved into a house with a largish garden and am looking
to landscape a 2 acre paddock alongside.

The paddock has 1 large trench down it, around 4ft deep and 12ft wide
running about 100 yds. It make mowing and groundcare a nightmare as my
tractor feels like its going to tip if I drive along it and misses
bits if I drive across it. The rest of the field also has shallower
channels/undulations of around 1ft deep by 10ft wide, which cause
problems.

Maybe the undulations were man-made to increase the surface area, but
in any case I would like to level it out but don't know where to
start.

I've got an old JCB digger and a tractor and trailer, but I would
imagine I would need literally hundreds of tons of topsoil to level
it.

I considered getting a power harrow for the undulations, would this
work? I can't see much choice but to get topsoil for the large trench
or make it into a pond, but am not keen on a pond there.