Our paper presents the results of research on the content of available phosphorus and the activity of alkaline and acid phosphatase in soil under winter triticale fertilized with cattle farmyard manure (FYM) stored in various conditions: aerobic, anaerobic, and aerobic, with burnt lime added. The experiment also involved nitrogen fertilization in the form of ammonium nitrate at various rates (0, 30, 60, 90, and 120 kgN·ha^-1). The content of available phosphorus from depths of 0-15 cm and 15-30 cm in soil was 58.87 mgP·kg^-1 and 53.33 mgP·kg^-1, respectively, which classifies the soil as class III with an average content of that element. We found a significant effect of the experimental factors on the content of available phosphorus. The highest content of that element was found in the soil (0-15 cm) fertilized with FYM stored under aerobic conditions with burnt lime added and non-fertilized with nitrogen (79.57 mgP·kg^-1). With a greater soil sampling depth (15-30 cm), the content of phosphorus decreased by about 12%. The application of FYM stored under aerobic conditions with burnt lime added resulted in a significant increase in the alkaline phosphatase activity in soil (1.00 mM pNP·kg^-1·hV for a depth of 0-15 cm, and 0.830 mM pNP·kg^-1·h^-1 for 15-30 cm). However, we found a significant inhibition of acid activity (1.381 mM pNP·kg^-1·h^-1 for a depth of 0-15 cm, and 1.275 mM pNP·kg^-1·h^-1 for 15-30 cm). We recorded a highly significant correlation between the content of available phosphorus and the activity of alkaline phosphatase in soil (r=0.731-0.879; p<0.05).