The aim of studies was to define the impact of pre-sown crop winter rye and buckwheat on the plant growth, yield and grain quality of spring cereals. During research there were evaluated the traits characterizing the yield and grain quality of wheat 'Uffo' and barley 'Rasa'. The soil of biological crop rotation within the period of two years on average was processed with 20.1 t ha -1 of buckwheat green manure or 5.4 t ha -1 buckwheat dry matter and 4.2 t ha -1 rye straws or 2.5 t ha -1 dry matter of rye straws. According to the chemical analysis, the buckwheat dry matter contained nitrogen and phosphorus, which was three times higher than dry matter of rye straws, potassium and calcium was two times higher, but magnesium - five times higher than dry matter of rye straws. Spring wheat 'Uffo' (4.36 t ha -1) and spring barley 'Rasa' (3.23 t ha -1) provided significantly (p
