The experiment described in the paper was carried out in 1997–2001. The successive effect of green manure in the form of forecrop plants on crops and selected elements of nutritive value of red beet was studied. Two forms of forecrop utilization were used – the whole biomass and post-harvest residues. The fertilizing effect of green manures was compared with farmyard manure at the dose of 25 t·ha^-1 and with cultivation without organic fertilization. Red beets were grown in the third year after organic fertilization. Green manure had a positive effect on red beet crops. The highest total and marketable yields were obtained after oat as well as the mixes of vetch with field pea and vetch with oat were ploughed under. The greatest amount of dry matter was found in red beet grown after field pea. The greatest sugar content was found in red beet grown after the mix of vetch with oat and field pea and after field pea.

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