I think the most common pronunciation for 久田 is Hisada. As far as I know this will just be a normal surname, and its not going to have any deeper meaning. I mean, individually the character 久 means long (as in time span) and 田 means field, but any speculation about how this originated or if it is intended to have a spiritual significance would just be a wild guess. (I really think it is just a name without any particularly deep meaning).
Kyuden, Kuden, Kuta, Kyuta are all possible readings, but Hisada (or Hisata) are probably the most common readings.