'Green fallow' definitions:

Definition of 'Green fallow'

From: GCIDE

Fallow \Fal"low\, n. [So called from the fallow, or somewhat yellow, color of naked ground; or perh. akin to E. felly, n., cf. MHG. valgen to plow up, OHG. felga felly, harrow.]
1. Plowed land. [Obs.] [1913 Webster]
Who . . . pricketh his blind horse over the fallows. --Chaucer. [1913 Webster]
2. Land that has lain a year or more untilled or unseeded; land plowed without being sowed for the season. [1913 Webster]
The plowing of fallows is a benefit to land. --Mortimer. [1913 Webster]
3. The plowing or tilling of land, without sowing it for a season; as, summer fallow, properly conducted, has ever been found a sure method of destroying weeds. [1913 Webster]
Be a complete summer fallow, land is rendered tender and mellow. The fallow gives it a better tilth than can be given by a fallow crop. --Sinclair. [1913 Webster]
Fallow crop, the crop taken from a green fallow. [Eng.]
Green fallow, fallow whereby land is rendered mellow and clean from weeds, by cultivating some green crop, as turnips, potatoes, etc. [Eng.] [1913 Webster]