Changes in floristic composition over three years of Ljubljana marsh grassland in relation to cutting and fertilising management

Abstract

A research in Ljubljana marsh was conducted from 2004 to 2006 with the aim to determine how the regime of cutting and fertiliser application over several years influences on the floristic composition of meadow sward. Field sampling plots in split-plot design with four replications were set up on two different types of grassland, one belonging to Arrhenatherion (sampling plot T1), the other to Molinion alliances (sampling plot T2) in 1999. The main plots represented the frequency of 4 cutting regimes (2 cuts with normal and delayed first one, 3 and 4 cuts per year) and sub-plots represented the fertiliser regime (no fertiliser, PK and NPK fertiliser with two different amounts of N). After five years, the cutting, and especially fertiliser application, significantly altered the floristic composition. In floristic composition of Arrhenatherion plot more frequent cutting in combination with higher amount of N fertilisation increased the proportion of grasses (92.7 % on a fresh matter basis). This was mostly observed in 2004. Legumes proportion (15.4 %) increased mainly on plots where PK fertiliser was used and a first cut was retarded. When N fertiliser was used on Molinion plot in all treatments with cutting herbs (forbs) increased their proportion up to 65 % in average. The proportion of legumes in sward of this plot was neglecteable that's way treatments did not have any special effect on them.