Microorganisms and organic carbon (C) pool composition are vital in regulating soil organic matter mineralization. However, our understanding of how parent materials and fertilizers affect this process is still limited. In this two-year study, the changes of cumulative soil organic C and nitrogen (N) mineralization and C and N pools (total, labile, and recalcitrant), C- and N-cycling enzymes, bacterial composition, and C- and N-cycling gene and their interactions were analyzed for soils developed on loess and river alluvium. These soils were under rice-rape seed rotation, and no fertilization (Control), NPK (NPK), and NPK plus organic manure (NPKM) were applied; treatments were arranged into a completely randomized design. Soil organic C mineralization was influenced by soil parent material and fertilization, whereas no interactive effects were found for soil N mineralization. The river alluvium promoted 2.24 times higher C and 1.27 times higher N mineralization than loess; fertilization intensified C and N mineralization in 1.70 and 1.22 times only in loess. Soil C and N fractions were influenced by the parent material, with 1.39 and 1.10 times higher effects found in soils formed on river alluvium. NPKM increased the content of total organic C in 1.31 times, labile C in 1.24 times, recalcitrant C in 1.34 times, total N in 1.21 times, and recalcitrant N in 1.17 times in loess soil. Similarly, in river alluvium soil, the increases were 1.41、1.21、1.53、1.23 and 1.28 times. Fertilization with NPKM increased C- and N-cycling enzyme activities in both soils. Parent material and fertilization shifted bacterial composition by changing pH, subsequently influencing N-cycling genes. However, only parent material affected C-cycling genes. Thus, C and N fractions play a direct role in the mineralization process of soil organic C, while bacteria indirectly influenced the C mineralization processes by promoting the enzyme activities.

微生物和有机碳（C）库组成对于调节土壤有机质矿化至关重要。然而，我们对母质和肥料如何影响这一过程的了解仍然有限。在这项为期两年的研究中，土壤有机质累积变化对黄土上发育的土壤进行 C 和氮 (N) 矿化、C 和 N 库（总、不稳定和顽固）、C 和 N 循环酶、细菌组成、C 和 N 循环基因及其相互作用进行分析和河流冲积层。这些土壤实行稻油轮作，不施肥（对照）、氮磷钾（NPK）、氮磷钾加有机肥（NPKM）；治疗被安排成完全随机的设计。土壤有机碳矿化受到土壤母质和施肥的影响，而土壤氮矿化没有发现交互作用。河流冲积层促进的C和N矿化比黄土高2.24倍和1.27倍；仅在黄土中，施肥就使C和N矿化强化了1.70和1.22倍。土壤 C 和 N 分数受母质影响，在河流冲积层形成的土壤中发现的效果高出 1.39 倍和 1.10 倍。NPKM使总有机C含量提高了1.31倍，不稳定C含量提高了1.24倍，顽固性C提高了1.34倍，总氮含量提高了1.21倍，顽固性氮含量提高了1.17倍。黄土。同样，在河流冲积土中，增幅分别为1.41、1.21、1.53、1.23和1.28倍。使用 NPKM 施肥增加了两种土壤中的 C 和 N 循环酶活性。母体材料和受精通过改变 pH 值来改变细菌组成，随后影响氮循环基因。然而，只有母体材料影响 C 循环基因。因此，C和N组分在土壤有机C的矿化过程中起直接作用，而细菌通过促进酶活性间接影响C矿化过程。