|If we consider that these fields are in fact big clock faces, on this image we can read the following times:
Upon going there, I found these results:
The circular motifs are created thanks to this centrally pivoting, irrigation system. An 'arm' distributes jets of water along the length of the steel structure which pumps water through it.
1/ Place the compass in the centre of the circle in the field, and stand facing North.
2/ Observe the direction of the irrigating arm and note its position with a pen: