Evaluation of optimal time and parameters for measuring potentially mineralized nitrogen in soil

Our research was done on brown forest soil with long-term experiments and with a system of fertilizing which is in use for 40 years. Experiment variants with an increasing dose of nitrogen fertilizer were chosen for this research. Two experiments have been performed: experiment in pots supplied with ammonium nitrate labeled with a stable isotope 15N (11.8%) and experiment in the field. The aim of the research was to establish which plant and soil parameters group (obtained in the controlled conditions and/or in the field) could be considered as reliable for evaluation of aerobic and anaerobic incubation and of the best time for estimation of potentially mineralized nitrogen in soil. According to the determined correlative dependence, it could be concluded that reliability of aerobic incubation should be estimated in October by plant and soil parameters from field, anaerobic incubation should be estimated in early spring (March) by plant and soil parameters, from controlled conditions (pots) and from field.