Phil L wrote:
..and didn't get a definitive answer, so I'm asking again.

I have noticed in farmers fields, huge piles of what appears to be a
blueish/greyish stone, I work in the construction industry and to me
it looks like MOT, or crush & run, but blue.
Upon closer inspection (IE picking it up) it has no odour, feels like
soft stone and the 'stones' range from 3 inch down to grit.
The piles of this I have seen in various (crop growing) feilds range
from 50 to 100 tonnes, and the farmers spread it over the entire
field round about this time of year....last time I asked, it was
suggested that the farmers were having drives laid or tracks for farm
machinery to drive on, since I've recently seen it being spread, I
know this is not the case, I cannot believe that it's for any kind of
drainage neither and I imagine it's fertilizer of some sort, has
anyone else seen this? - does anyone know what it does or what it's
called?

TIA

In reply to some, most or all of the answers so far...it may be sewage I
don't know, but it has no odour at all, it was being spread on crop fields,
almost all the fields around here are crops, very few animals.
Lime is a slight possibility, but would a farmer want stones, some as big as
a fist, spread on his land?
The colour of it is blue/white...more white than blue, if you know what I
mean, just a slight blue tinge to it.
The heaps of it are massive, easily 60 tonnes on a ten acre field....I'll
have to take some photos next W/E and post them somewhere, I don't know any
farmers to ask, the only one I do know is a pig farmer and he doesn't grow
anything, apart from bacon!