THE EFFECT OF PROLONGED DIVERSE MINERAL FERTILIZATION ON NEMATODES INHABITING THE RHIZOSPHERE OF SPRING BARLEY

The studies embraced nematodes occurring in the rhizosphere of spring barley grown in experimental held divided into small plots fertilized for many years with the same set of mineral fertilizers: N, P, K, NPK, CaPK, CaNP, CaNK, CaNPK, and Ca or not fertilized at all (O). The stu dy was carried out for three years. The first samples were taken in th e 22nd year of fertilization. The fertilization did not differentiate greatly the structure of nematode communities. In all combinations of fertilizers plant and bacterial feeding nematodes dominated. Hyphal fe eding nematodes occurred in all combinations but were less abundant th an plant and bacterial feeding groups, omnivores and predators occurre d only in some samples and their densities were low. Treatment was not observed to cause recurrent changes in total density and the density of plant and bacterial feeding nematodes. Such changes were noticed in the case of hyphal feeding nematodes. High density of them was connec ted with NPK application. The dominated genus of this group Aphelencho ides was significantly more abundant in NPK treatment than in the cont rol (O). The application of Ca alone had a negative effect on Pratylen chus. This genus was significantly less abundant in Ca than in NPK, N, P or K treatments. The frequency of individual species of Pratylenchu s was not affected by type of fertilization.