Impact of soil pH on nitrogen mineralization in grassland soils

Abstract

The aim of the investigations was to evaluate the impact of soil pH on the efficiency of nitrogen mineralization for two forms of nitrogen fertilizer --- ammonium nitrate (AN) and calcium nitrate HYDRO (CN). The investigations were performed in long-term grassland experiments on mineral soils. Unlimed objects (Ca0) and those limed in 1981 with calcium carbonate (Ca2) were chosen. Nitrogen content was determined by the in situ method. N-NO3 and N-NH4 content was determined in soil samples and the total amount of mineral nitrogen (N-min) was calculated. A higher pH increased the efficiency of mineralization. A lower pH favoured the accumulation of ammonium ions. This phenomenon was not observed when calcium nitrate was used as the fertilizer. Differences in soil pH affected the total mineralization efficiency only to a small extent. Calcium carbonate promoted nitrogen mineralization at a higher soil pH.