Die Bodenkultur - Journal for Land Management, Food and Environment


C - and N-transformation dynamics in the soil


The C- and N-transformation processes were measured over a 11 day-incubation period under laboratory conditions in a calcareous sandy and a chernozem soil. The experiment was carried out with and without glucose carbon source under different N nutritional conditions. The water content of the samples was set to a moisture value corresponding to 70 % of the maximum water holding capacity The C02 production and the ammonium- and nitrate-N content of the soil samples were determined periodically during the incubation period. Between the samplings on day 0 and day 2, the ammonium-N quickly nitrificated. In the presence of glucose, mineral nitrogen was immobilized simultaneously. Between the samplings on day 3 and day 11, the N immobilization and mineralization processes were approximately equal C02 production in soil samples incubated with glucose and different quantities of N-supply reached a high value already in the first two days of incubation, except the soil sample incubated with glucose and without N-fertilizer. Later, the intensity of glucose decomposition was controlled by the rate of mineralization of the organic N-compounds of the soil. Key-words: C- and N-transformation, soil, microbiology.