The aim of the study was to determine changes in the physico-chemical properties of soil caused by long-term manure and mineral fertilization and mineral fertilization. The trials were conducted in 1998–2001. They involved the fourth rotation in a long-term field experiment, which was established in 1986. In grey-brown podzolic soil formed from loamy clay the following crops were grown in crop rotation: sugar beet, spring barley, maize, spring wheat. Prior to the investigations, the arable layer of soil was slightly acidic. The capacity of the sorptive complex, which was saturated with bases to 72.1%, was 75.7 mmol (+) kg-1. The experiment was set up in a random block design with four replications on two fields. On one field mineral fertilization was carried out together with manure fertilization. On the other field, the crops received only mineral fertilizers. Fertilization with different rates of nitrogen, potassium, magnesium and calcium (eight objects) was maintained on the same level on both fields. Soil samples for analyses were taken from the arable soil layer after harvest. The chemical analyses comprised pH, hydrolytic acidity, cation exchange capacity (Ca2+, Mg2+, K+, and Na+). Mineral fertilizers applied without manure depressed the soil pH, with a particularly strong adverse effect observed in the case of higher nitrogen rates. Manure could largely counteract this negative effect. Likewise, liming, applied with or without manure fertilization, had a positive effect. In the fourth rotation a significant decrease in the soil sorptive capacity, total bases and base saturation of soil was observed when mineral fertilizers were applied alone. Base saturation depended on both manure and mineral fertilization. The ratio of Mg2+ and K+ in the sorptive complex was better when the crops grown in rotation were fertilized with minerals and manure.