Daunting task. Plot gonna take a while to get sorted.

All plant material, wood, paper nad cardboard can be burnt on the plot and is the best way of disposing of perennial weeds and roots. The ash is very good for the soil, particularly on heavy clay soils but the fertiliser content rapidly washes out after rain.

Try to site the fire near where you will be digging first so that it can be of benefit to the crops that will be planted in a few weeks time.