Net N-mineralisation related to soil organic matter pools

Soil organic maer and its turnover rate are key parameters for agricultural management practice as well as for envi- ronmental issues. In a field experiment comparing organic (compost) and mineral fertilisation and combinations of both the amount of inorganic nitrogen in the soil and the nitrogen uptake by the plants were measured. Considering these data and the fertilisation practice the net N-mineralisation during the vegetation periods 1996-2001 was estimated for six fertilisation treatments. Simultaneously the nitrogen dynamics in the soil were calculated using the STOTRASIM model, which takes into account four soil organic maer pools of different turnover rate. A close relation was found between the amount of a slow decomposable fraction and the net N-mineralisation during the vegetation period.