NITROGEN DYNAMICS IN THE SOIL AFTER NATURAL ZEOLITE APPLICATION

The dynamics of nitrate and ammoniac nitrogen in soil after the application of zeolite of various amounts was monitored. The decreased ammonium content was apparent one month after zeolite application compared to the variants without zeolite due to the specific fixation of NH4 broken vertical bar cations on the zeolite lattice (92.5 mg at the control variant and 77.2 - 81.0 mg per kg of soil at the tested variants). Three months later, an ammonium content increase of 24-59 % at the variants with zeolite was observed in comparison with the control variant due to the gradual ammonium release from the zeolite lattice. Six months after zeolite application into the soil, statistically significant differences were found not only between the control variant and variants with zeolite, but also among individual variants with various zeolite dose (H=14.201; p=0,003 according to the Kruskall-Wallis test). The nitrification process in the soil is less intense due to the influence of applied zeolite. In the autumn period, the nitrate nitrogen content in the soil decreases by 66-78 % compared to the control variant, therefore, the nitrate leaching from the soil horizons to the ground water is less. In summary, zeolite can be considered as a slow releasing nitrogen fertilizer.