Biogeochemical weathering of bedrock is the most important input of silicon (Si) and phosphorus (P) to forest ecosystems. While soil microbes, and in particular P-solubilizing bacteria (PSB), are known to accelerate the solubilization of Si and P from silicate rocks, our understanding of the mechanisms driving biogenic weathering are still limited. To fill this gap, incubation experiments with weathered parent materials (i.e. basalt, andesite and paragneiss) of four soils and water extracts of the four soils, differing in P stocks, were conducted. We found that the net Si solubilization rate ranged from 5.0 (±1.8) to 91.0 (±2.4) nmol m⁻² d⁻¹ across all examined soils. The silicate dissolution rates were negatively related to the decrease in pH (ΔpH) and positively related to the amounts of organic acids released by microbes. We found that the gross P solubilization rates from the parent materials were ∼11 times higher at the P-rich site (BBR) compared to the P-poor site (CON). In addition, we determined the abundance and the taxonomic composition of PSB communities in the four soils. The abundance of PSB ranged from 2% at the P-rich site to 22.1% at the P-poor site, indicating that a selective pressure exists in P-poor soils towards a higher abundance of P-solubilizers. Yet, despite the relative high abundance of PSB, the gross P solubilization rates were low in the soils derived from P-poor parent material. The genus Pseudomonas was found only in the PSB community at the P-poor site. Burkholderiales and Bacillales together were by far the two most abundant orders among the PSB communities in all soils and depths. In conclusion, this study shows that PSB are more abundant in P-poor soil than in P-rich soil, while the weathering rate seems to be mostly dependent on the bedrock.

基岩的生物地球化学风化作用是森林生态系统中硅（Si）和磷（P）的最重要输入。尽管已知土壤微生物，尤其是P增溶细菌（PSB）会加速硅酸盐和岩石中Si和P的增溶，但我们对驱动生物风化机理的理解仍然有限。为了填补这一空白，进行了用四种土壤风化的母体材料（即玄武岩，安山岩和石蒜）和四种土壤的水提取物（磷储量不同）的温育实验。我们发现净Si增溶速率的范围为5.0（±1.8）至91.0（±2.4）nmol m ^-2 d ^-1在所有检查过的土壤上 硅酸盐的溶解速率与pH（ΔpH）的降低呈负相关，与微生物释放的有机酸的量呈正相关。我们发现，与贫磷位点（CON）相比，富磷位点（BBR）母体材料的总磷溶解率高约11倍。此外，我们确定了四种土壤中PSB群落的丰度和分类学组成。PSB的丰度范围从富P点的2％到P贫点的22.1％，这表明P贫土中存在着向P增溶剂更高的选择性压力。然而，尽管PSB的含量相对较高，但在贫P母料来源的土壤中总P溶解率却很低。属假单胞菌仅在P贫乏站点的PSB社区中被发现。迄今为止，伯克霍尔德里亚人和巴卡莱勒人在所有土壤和深度上都是PSB社区中最丰富的两个秩序。总之，这项研究表明，贫磷土壤中的PSB比富磷土壤中的PSB含量更高，而风化速率似乎主要取决于基岩。