Mean weed biomass values confirmed the high weed infestation in field M2, with 0.72 t ha-1 across both treatments and the maximum value of 2.81 t ha-1. In M1 the dry weed biomass was lower than for M2. The experimental fields of the second year had similar level of weed infestation, both in terms of mean (about 0.35 t ha-1) and maximum biomass values. The differences of weed biomass among treatments within each field were not significant except for M1.