Production of thin, flexible glass films by evaporation of glass in high vacuum

Abstract

The most probable number (MPN) method was used to estimate how numbers of autotrophic nitrifiers in Myrtillus-type and Calluna-type pine forest soils in southern Finland were affected by seven different fertilization treatments. No NH+4 oxidizers and only a few hundred NO2−1 oxidizers g−1 of soil were found in unfertilized organic (O) horizons. Ammonium nitrate and nitroform (ureaformaldehyde) had hardly any effect on the nitrifiers. Urea, alone or applied together with apatite + biotite or with apatite + biotite + micronutrients, increased numbers of NH4+ and NO2− oxidizers. Wood ash, alone or with apatite, also had a stimulative effect. The effects of the stimulative fertilizers were less in the A2 horizon than in the O horizon. The MPN counts were considerably affected by the duration of incubation: counts of NH4+ oxidizers kept increasing for at least 8 weeks and counts of NO2− oxidizers for at least 15 weeks. These MPN counts were compared with earlier results from incubation experiments on the same soils to find out how they reflect changes in soil nitrification after fertilization.