fallow

1 :  usually cultivated land that is allowed to lie idle during the growing season

2 obsolete :  plowed land

3 :  the state or period of being fallow Summer fallow is effective for destroying weeds.

4 :  the tilling of land without sowing it for a season

:  to plow, harrow, and break up (land) without seeding to destroy weeds and conserve soil moisture

1 :  left untilled or unsown after plowing

2 :  dormant, inactive —used especially in the phrase to lie fallow at this very moment there are probably important inventions lying fallow — Harper's

:  not tilled or planted fallow fields