Vašák F., Černý J., Buráňová Š., Kulhánek M., Balík J. (2015): Soil pH changes in long-term field experiments with different fertilizing systems. Soil & Water Res., 10: 19-23.The changes of soil pH in long-term 14-year field experiments with different fertilizing systems are described. The field experiments were located at four sites of the Czech Republic with different soil and climatic conditions (Červený Újezd, Hněvčeves, Lukavec, and Prague-Suchdol). At each site, the same fertilizing systems and crop rotation (potatoes -winter wheat -spring barley) were established. Six experimental treatments were applied to crop rotation: (1) unfertilized treatments (control); treatments with organic fertilization: (2) farmyard manure (FYM), (3) sewage sludge (SS); treatments with mineral fertilizers: (4) nitrogen (N), (5) nitrogen with straw application (N + straw), and (6) nitrogen with phosphorus and potassium (NPK). The long-term effect of fertilizers significantly depends on soil conditions. At the site Prague-Suchdol minimal differences in the soil pH were observed by all treatments. This is caused by the high buffering capacity of Chernozems against the soil acidification. At Červený Újezd (Haplic Luvisol), Hněvčeves (Haplic Luvisol), and Lukavec (Stagnic Cambisol) sites, soil pH decreased by all treatments. Only at Hněvčeves site the soil pH did not change with N treatment. The highest soil pH decrease in the treatment with NPK (ΔpH -0.89) and N + straw (ΔpH -0.70) was observed at Hněvčeves site. By the treatments FYM and SS the highest decrease was registered at Červený Újezd (ΔpH of about -0.30 and -0.63, respectively). The highest decrease in control treatment (ΔpH of about -0.63) was observed at Lukavec site. The results showed that to evaluate long-term soil pH changes a whole complex of factors must be examined.