Effectiveness of the Application of Nitrification Inhibitors on the Content of Available Nitrogen Forms in the Soil after Winter Barley Cultivation

The aim of this study was to examine the effect of split and one-time application of nitrogen-sulphur fertiliser ENSIN (26% N, 13% S) containing nitrification inhibitors (dicyandiamide and 1,2,4-triazole) on the content of nitrate and ammonium nitrogen in soil. The study was conducted in field small-plot experiment with winter barley on Haplic Luvisol with dominance of clay fraction in experimental station of the Central Testing Institute in Agriculture of Veľké Ripňany in the experimental years 2015 to 2017. The dose of nitrogen in all experimental treatments was 140 kg/ha and was applied at once during regenerative fertilisation or split in three partial doses. Soil samples from all examined treatments were taken from two soil depths (0.0‒0.3 m and 0.3‒0.6 m, respectively) by probe rod in three week intervals. Achieved results indicate that in the year 2015/2016, one-time application of fertiliser ENSIN containing nitrification inhibitors considerably reduced portion of N-NO3 - from the content of Nmin by 32 relative % in soil depth of 0.0-0.3 m and by 36 relative % in soil depth of 0.3‒0.6 m. On the other hand, in the year 2016/2017, split application of fertiliser ENSIN substantially reduced portion of N-NO3 - from the content of Nmin by 38‒62 relative % in soil depth of 0.0‒0.3 m, however increased portion of N-NO3 - by 10‒14 relative % in soil depth of 0.3‒0.6