Bacterial decomposition of organic matter in soils is generally believed to be mainly controlled by the access bacteria have to organic substrate. The influence of bacterial traits on this control has, however, received little attention. Using the substrate-dependent Monod growth model, we develop a bioreactive transport model to screen the interactive impacts of spatial dispersion and bacterial traits on mineralization. Bacterial traits primarily involved in the bacterial response to the substrate concentration, such as the maximum specific uptake rate and efficiency, the adaptation time of the uptake rate and the initial population density, are considered. We compare the model results with two sets of previously performed cm-scale soil-core experiments in which the mineralization of the pesticide 2,4-D was measured under well-controlled initial distributions and transport conditions. Bacterial dispersion away from the initial substrate location induced a significant increase in 2,4-D mineralization. It reveals an increase of specific uptake rates at lower bacterial densities, more than compensating the decrease of specific uptake rates caused by substrate dilution. This regulation of bacterial activities by density, caused by the local depletion of substrate by competing bacteria, becomes dominant for bacteria with an efficient uptake of substrate at low substrate concentrations (a common feature of oligotrophs). Such oligotrophs, commonly found in soils, compete with each other for substrate even at remarkably low population densities. The ratio-dependent Contois growth model, which includes a density regulation in the expression of the uptake efficiency, is more accurate and convenient to calibrate than the substrate-dependent Monod model, at least under these conditions. In view of their strong interactions, bioreactive and transport processes cannot be handled independently but should be integrated, in particular when reactive processes of interest are carried out by oligotrophs.

一般认为土壤中有机质的细菌分解主要受细菌对有机基质的访问控制。然而，细菌性状对这种控制的影响很少受到关注。使用依赖于底物的 Monod 生长模型，我们开发了一个生物反应性运输模型来筛选空间分散和细菌特征对矿化的交互影响。考虑了主要涉及细菌对底物浓度反应的细菌性状，例如最大比吸收率和效率、吸收率的适应时间和初始种群密度。我们将模型结果与之前进行的两组厘米级土壤核心实验进行比较，其中农药 2 的矿化，4-D 是在控制良好的初始分布和运输条件下测量的。远离初始基质位置的细菌分散导致 2,4-D 矿化显着增加。它揭示了在较低细菌密度下比摄取率的增加，超过了对底物稀释引起的比摄取率下降的补偿。这种由竞争性细菌局部消耗底物引起的密度对细菌活性的调节，对于在低底物浓度下有效吸收底物的细菌变得占主导地位（寡养生物的一个共同特征）。这种在土壤中常见的寡养生物即使在极低的种群密度下也会相互竞争底物。比率相关的 Contois 增长模型，它包括吸收效率表达式中的密度调节，至少在这些条件下，比依赖于底物的 Monod 模型更准确和更方便校准。鉴于它们的强相互作用，生物反应和运输过程不能独立处理，而应整合，特别是当感兴趣的反应过程由寡养生物进行时。