Wpływ wczesności gatunków i odmian traw na ich udział i plonowanie w mieszankach łąkowych

The aim of the studies was understanding of changes of share in the yields of grass species and cultivars which were used in 4 mixtures. They were differentiated in the earliness of cuts and in the following years after sowing. The aim was also estimation of mixture yielding in the conditions of three cut management depending on nitrogen fertilization. The field trials were carried out in the 1993 (sowing year) - 1995 at the wet meadow site on the black - loam soil. Two rates of nitrogen (80 and 160 kg N/ha per year) were applied. It was found the changes in percentage of grass species and cultivars in the following years were similar while their share in the yields in the specific year depended on the cultivar. The yields of mixtures differentiated in the earliness were similar and in general yields of early and late mixture were lower. The higher rate of nitrogen often caused the significant increase of the mixture yields.