The influence of fertilization on natural grassland phytocenose composition

In order to improve the natural grassland productivity and quality, it is important to evaluate the influence of fertilization of natural sward botanical composition. The research aim: to investigate the effect of nitrogen, phosphorus and potassium fertilizers and their combinations on sward botanical composition. Experiments were carried out in the year 2015 at Alexandras Stulginskis University Experimental Station of the long-term grassland fertilization experiment of Agricultural and Food Sciences Institute. Increasing nitrogen fertilizer rates significantly reduced proportion of legume grasses in phytocenose. The greatest influence on the increasing quantity of legume grasses in the sward had phosphorus fertilizers, but significant difference was obtained only at rate of 160 kg ha-1. Potassium fertilizer rate increased up to 150 kg ha-1 increased proportion of legume grasses in the phytocenose. The combinations of fertilizers significantly increased the part of legume grasses in sward compared with control treatment. Fertilization with nitrogen, phosphorus and potassium fertilizers and their combinations significantly increased proportion of grain grasses in sward. The highest amount of grain grasses was obtained in sward fertilized with maximum nitrogen and phosphorus rate and NPK combinations. Minimum and maximum rate of nitrogen fertilizers significantly reduced proportion of forb grasses in sward phytocenose. The amount of forb grasses in sward was higher under fertilization with nitrogen fertilizers and combination of nitrogen and phosphorus compared with this under fertilization with potassium and phosphorus fertilizers and their combinations. Potassium and phosphorus fertilizer, nitrogen and potassium combination and NPK combinations significantly reduced the amount of forb grasses in swardVytauto Didžiojo universitetasŽemės ūkio akademij