adjective

(of farmland) ploughed and harrowed but left for a period without being sown in order to restore its fertility or to avoid surplus production.

incentives for farmers to let land lie fallow

uncultivated,unploughed,untilled,unplanted,unsown,unseeded,unused,undeveloped,dormant,resting,empty,bare,virgin,neglected,untended,unmaintained,unmanaged

noun

a piece of fallow land.

a great estate was usually divided between fallows, grazed stubble, and wheat

verb

leave (land) fallow for a period.

fallow the ground for a week or so after digging