An effort at a bit of volksetymologie: "fallow" sounds a bit like "furlough" so I looke that up. Not related.

furlough

SYLLABICATION: fur·lough
PRONUNCIATION: fûrl
NOUN: 1a. A leave of absence or vacation, especially one granted to a member of the armed forces. b. A usually temporary layoff from work. c. A leave of absence from prison granted to a prisoner. 2. The papers or documents authorizing a leave: The soldiers had their furloughs in their breast pockets.
TRANSITIVE VERB: Inflected forms: fur·loughed, fur·lough·ing, fur·loughs
1. To grant a leave to. 2. To lay off (workers).
ETYMOLOGY: Alteration of vorloffe, furlogh, from Dutch verlof, from Middle Dutch. See leubh- in Appendix I.