The main objective of the current study was to evaluate the effects of six legume species ( Trifolium pratense, Medicago sativa, Trifolium repens, Galega orientalis, Medicago lupulina, Trifolium resupinatum) ploughed down as green manure, on the seed yield of timothy ( Phleum pratense) and meadow fescue ( Festuca pratensis). Legumes were undersown into barley. In the first year of production legumes were chopped and ploughed down for green manure in June. The sown timothy and meadow fescue were used for organic seed for three years. Although T. resupinatum grew well in the year of sowing it completely disappeared after winter. Based on 3-year mean production data, the highest timothy and meadow fescue seed yield was obtained after ploughing down a mixture of three legumes ( T. pratense+ M. sativa+ T. repens). Seed yield increased by 27.8-33.1%. Ploughed-down pure legumes (except G. orientalis) gave a lower but significant increase in seed yield. Having ploughed down legumes, the positive effect on organic seed was more substantial in the second and third years of production.
