Dry straw will not ferment. DMR wets straw on a platform for 24 to 48 hours until it reaches about 75 per cent moisture, and puts the water requirement at around 4000 litres per tonne of raw material. Run the leachate back over the heap instead of letting it drain away, because it carries nutrients with it.
Straw takes water slowly. A single soaking on the morning of stacking wets the outside and leaves the middle of each bale dry, and that dry core never joins the process. Give pre-wetting its own day in the schedule.