The investigations were carried out in 2002 - 2005, on proper grey-brown podsoilic soil originating from light loam (class IIIa in the soil valuation system, very good rye complex), on the basis of a two-factor experiment established in 1986 according to the random block design with four replications. The arable horizon of the soil, before the experiment, was characterized by slightly acidic reaction (pH 1 mol KCl dm-3 was 6.2) and the concentrations of available nutrients were as follows: 100.0 mg K, 53.2 mg Mg and 41.3 mg P kg-1 of soil. Soil samples for chemical tests were collected from the arable layer after harvesting crops grown in a rotation: sugar beet, spring barley, maize and spring wheat. The content of available forms of phosphorus and potassium were determined by Egner-Riehm method (DL), and that of manganese using Schachtschabel’s method. The purpose of the study has been to determine the influence of mineral fertilization with or without FYM on the content of available macronutrients in soil. The statistical analysis of the results have shown a significant influence of manure on the level of available P, K and Mg in the tested soil. When both FYM and mineral fertilizers were introduced to soil, its abundance in available magnesium was 2.6-fold higher than after mineral fertilization alone had been applied. FYM raised nearly 3-fold the content of available forms of potassium in soil compared to the content found when only mineral fertilization was used.