ln  1996,  a  field  experiment  was  set  up  on class  llla soil,  which consisted  of 6 trials: 1  - bare  fallow,  2  - fallow  land seeded with annual   plants,   3  - field swarded  with  goat's rue  (Galega orientalis Lam.), 4 - traditional fallow,  5 - field swarded  with  a  mix  of goat's rue (Galega orientalis  Lam.) and  aweless  brome (Bromus  inermis),  6  - field  swarded  with aweless  brome  (Bromus  inermis). During   the tests,  no  agrotechnical   measures   were  carried  out  apart   from periodical  mechanical   weeding  of the  bare  fallow  and  the  sowing  of annual  plants.   Plant   samples  for  chemical  analyses  were  taken from  the  swarded fields; the  remaining  biomass  was  left  on the fields.  After  each growing  season, soil  samples  were collected in four replicates  from  the  0-25 cm and  25-50 cm soil  horizons,  for determination of the  content of Cu,  Zn  and  Mn  available forms. This paper  discusses  the  results  obtained in  2000-2007. The  experiment has demonstrated  that  the  way  farmland was  laid  fallow  or set-aside had  an  effect on concentrations  of the  available forms  of Cu,  Zn  and Mn  in  the  0-25 and 25-50  cm  soil  horizons.   Particularly  large changes  occurred  in  the  levels  of Zn and  Mn. The  way  set-aside arable land  was  kept  had  a  weaker  influence  on the  concentrations of easily  soluble  forms  of copper. By  seeding  annual   plants and leaving  the  grown  biomass on a set-aside field,  it was  possible to maintain the soil abundance  of available Zn on a high level  and  that  of Cu  and  Mn  - moderately  high.  Keeping  soil  as  bare  fallow  favoured better  accumulation of available forms  of copper and  manganese.