[Influence of N-serve on mineral nitrogen forms and microorganisms of the soil (author's transl)].

In a model experiment with soil, 2 stages of nitrogen (without additional N and with 200 kg N/ha in the form of ammonia) and 3 N-Serve stages (without inhibitor and with 0.25 per cent and 1 per cent of inhibitor, relative to 200 kg of N/ha) were followed up over a period of 3 and 6 weeks, respectively, with respect to the dynamics of the nitrification process, the saprophytic soil microorganisms, and the autotrophic nitrifiers. In a second experiment, the ammonia form of nitrogen was substituted by the nitrate and nitrite form, respectively. No serious influence on the heterotrophic soil micro-organisms could be detected in any experimental variant; N-Serve was slightly stimulating, the autotrophic nitrifiers were noticeably depressed by N-Serve. The nitrification process could clearly be proved after 3 weeks already; by N-Serve it was remarkably delayed. Nitrite that had been added to the soil was scarcely transformed into nitrate, whereas it was somewhat more ammonified. The high loss of nitrogen in the nitrite variant cannot be caused by denitrification alone. When nitrate was used, the nitrification was not delayed.