K wrote:

CWatters writes
It's well known that Poppies thrive on disturbed ground. They pop up on road
verges after road works and on battlefields.

What is it about disturbed ground that makes this happen?

It's nothing about disturbed ground.

It's entirely about poppy seeds. They
a) are viable for a long time
b) are triggered into germination by light

Viable poppy seeds are widespread. When the ground is disturbed, some of
the seeds are brought to the surface and will germinate. The advantage
of this to the poppy is that they do not have to face much competition
from other plants. They are annuals - ie they grow, flower and produce
seeds in the course of a season, so by the time other plants have
colonised the bare ground, the poppies have produced their seeds, which
are now waiting in the soil for the next disturbance.

I once did a sales demonstration of a plough on a farm where, the farmer
told me, he and his father had never ploughed deeper than 6 inches in
over 40 years. A visiting farmer asked me how the plough would perform
at 8" or 9". I set the plough deeper and ploughed a couple of strips at
this depth before setting the plough back to 6". That summer, right
across the middle of the field, appeared the most glorious show of
poppies in the parish. As it was in the middle of a corn field the
farmer was not amused. It was the first time they had seen poppies in
that field in all of that time.