Performance of a simulation model describing protozoa-induced mineralization of bacterial C and N in a sandy loam

Mathematical modelling of a microcosm experiment provided a rigorous link between soil organism populations and the processes in the C and N cycles for a clay loam soil. In order to check the internal consistency of the model, we tested its performance with the data set obtained for a sandy loam. We empirically lowered the value of the half saturation constant for the protozoan consumption of bacteria from 175 to 50 (μg C g−1 soil) and initialized the state variables with the appropriate values. The model was also used to quantify the effect of texture on bacterial-protozoan interactions and flows of C and N using the simulated data for a clay loam and a sandy loam. The CO2-C evolved during the first 12 d was mainly due to glucose addition (180 μg C g−1 soil) and cycling of C in the soil (130 μg C g−1 soil). During this interval, C inputs into bacteria were 14-fold greater than the initial pool size. Protozoa increased total CO2-C evolution by 16% and increased net NH4-N mineralization 3.5-fold compared w...