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Fertilization with different amounts of mineral nitrogen (0 do 300 kg N /ha) have been applied continuously in eleven years investigation period, from 1996 till 2006 in stationary field experiment. Trial treatments included annual fertilization with different mineral nitrogen doses, respectively with 0, 100, 150, 200, 250 and 300 kg N/ha what imply total nitrate nitrogen input in eleven years investigation period of 0, 1100, 1650, 2200, 2750 and 3300 kg N/ha. This paper presents results of total nitrogen, nitrate and ammonium nitrogen content in soil at three investigation depth (0-30 cm, 30-55 cm and 55-80 cm), furthermore nitrate and ammonium concentrations in lysimeter water, analyzed during the 1996 and eleven years latter (2006) which have been measured in frame of EU LIFE Project, Development of the Croatian soil monitoring programme with a pilot project. At the beginning of investigation, mean value of total nitrogen content in soil at 0-30 cm depth were 0.16 %, at 30-60 cm depth 0.10 % and at 60-90 cm depth 0.04 %. Differences in total nitrogen content have been noted after eleven years of fertilization applying, in trial treatment without applying nitrogen in decreasing of total nitrogen content in soil, and in trial treatments with 200, 250 and 300 kg N/ha nitrogen applying in increasing of total nitrogen content in soil, but different according to soil depth. Variability of nitrate concentrations in lysimeter water has been observed. A lot of different parameters have influence on nitrate concentrations in water, but we noted a presence of correlation between fertilization and nitrate concentrations in lysimeter water. If we compare 1996 when average nitrate concentrations in water highly varied regardless the amount of fertilization, with correlation coefficient 0.43, eleven years latter variability shows complete correlation with applied amounts of total nitrogen (r = 0.90). |
