One field, a different colour every June, and nobody knows why
What is observed
About two hectares that ripen roughly ten days earlier than the surrounding crop, every year, in the same shape.
What it is not
Not a soil boundary on any map, not a drainage line, and not a difference in management. All three have been checked.
What it might be
A buried feature, which would show in dry years and does not. Or something entirely different that nobody has suggested.
