Notts have a good record of getting games on in recent years in wintry conditions, I think this is only the 2nd time in the 2020s we've had a home game PPd due a frozen pitch, the other being Chorley in the FA Trophy December 2022.
Under-soil heating would seem to be big waste of money, especially when you factor in the potential for games to be called off due to dangerous roads/pavements outside the ground if the weather is THAT bad.