EN
The aim of this study was to evaluate and compare the spatial variability of total nitrogen (TN), mineral nitrogen content (N-NO₃ and N-NH₄) and activities of the enzymes involved in the soil N cycle (urease – UR, nitrate reductase – NR, arginine deaminase activity – ADA) in a Luvisol surface horizon. Fifty soil sampleswere collected in a square sampling grid (10 m x 10 m) system. The results were evaluated using classic statistical and geostatistical methods. Most of the studied properties were distributed normally with the exception of NR activity and nitrate nitrogen (N-NO₃) content, which were distributed log-normally. Variation of coefficients (CV%) for total and mineral nitrogen forms was low, for UR and ADA activities moderate, and for NR activity high. The contribution of nugget variance in total variability (sill) was noted for UR and NR activities, and for TN content. The ranges of spatial influence calculated for the values of the studied properties ranged from 10-40 m. Kriged maps showed that soil UR and ADA activities and N-NO₃ content were irregularly distributed in the soil surface horizon, while more regular spatial distribution was noted for NR activity and for TN and ammonium nitrate (N-NH₄) content.