How to deal with a field of weeds
I have rented a small field off a farmer (half a football pitch) that I am allowed to turn into a garden. For the first year, I am only going to grow the boundary hedges and turn the field to grass. The field was head high with weeds (thistle, stingers and bramble) which I cut down with a brush cutter. The ground is very uneven so I am going to hire an excavator and driver to level the ground for me.
My question is: what do I do with the weeds? Do I get the driver to scrape the ground level, smash the weed roots and leave in place, or; do I scape the top surface off and move the soil to a heap. Problem with that is it would be a big heap.
If I left the weeds in place after levelling, which would be my choice, will it be necessary to kill the weeds before seeding my grass-seeds in September? If I have to kill, I assume I will use a poison.