EN
Since 1970 two meadow experiments were carried out in the IMUZ Experimental Station in Jaworki to study the influence of longterm various fertilization on the properties of the meadow ecosystem. The respective investigation presented the effects of different fertilization and application of NPK (I - without fertilization, II - PK, III - PKN - 60, IV - N-60, V - PKN-120, VI - N-120, VII - PKN-180, VIII - N-180, IX - PKN-240, X - N-240) on grassland yield. The most constant yield - over a long period of time - was obtained in full NPK and PK fertilization in the I experiment on the 600 m a.s.l. A significant yield decrease was observed after 15 and 20 years of the experiment (tab. 1). After this time a meadow renovation should be done. When pure nitrogen was applied the decrease in yield was observed after 10 years. In the II experiment (800 m a.s.l.) the decrease in yield was notified after 5 years of using, particularly on fields where only nitrogen was applied. This means that these areas are less useful for cultivating meadows.