Aggregate carbon (C) pools, which are closely associated with soil organic C (SOC) stability and agricultural productivity, are greatly affected by the composition of soil organic matter (SOM) functional groups. However, the long-term effect of different rice-based rotations on the composition of SOM functional groups remains elusive. In this work, a 10-year field experiment was conducted to assess the effect of different rice-based rotations (rice-wheat [RW] and rice-oilseed rape rotation [RR]) on the composition of SOM functional groups and soil aggregate C pools. The composition of SOM functional groups was determined by the nuclear magnetic resonance spectroscopy method. Aggregate C pools were isolated through density gradient fractionation. After 10 years of rice-based rotation, compared with RW, RR significantly reduced the proportion of macromolecular functional groups (nuclear magnetic resonance zone (NMR) > 110 mg kg^–1) in SOC, especially that of aromatic C (by 25.0%) and carboxyl C (by 26.8%), but significantly increased the contents of SOM compounds, particularly those of polysaccharides (by 30.7%), nitrogen carrier (by 28.4%) and lipids (by 34.7%). RR enhanced the proportions of large macroaggregate (by 56.0%) and intra-microaggregate particulate organic C (iPOC) (by 13.0%), as well as the SOC content (by 12.7%) relative to RW. Structural equation modeling revealed that RR could promote aggregate development and the stock of SOC as iPOC by enhancing the proportion of small functional groups in SOM (NMR < 110 mg kg^–1) and promoting SOM compound formation, thereby improving soil C pool stability and content relative to RW in the long-term rotation.

与土壤有机碳 (SOC) 稳定性和农业生产力密切相关的总碳 (C) 库受土壤有机质 (SOM) 官能团组成的影响很大。然而，不同水稻轮作对 SOM 官能团组成的长期影响仍然难以捉摸。在这项工作中，进行了为期 10 年的田间试验，以评估不同的水稻轮作（水稻 - 小麦 [RW] 和稻 - 油菜轮作 [RR]）对 SOM 官能团和土壤团聚体 C 组成的影响池。SOM 官能团的组成通过核磁共振光谱法确定。通过密度梯度分级分离聚集体 C 库。经过10年的水稻轮作，与RW相比，^–1 ) 在 SOC 中，尤其是芳香族 C（增加 25.0%）和羧基 C（增加 26.8%），但显着增加了 SOM 化合物的含量，特别是多糖（增加 30.7%）、氮载体（增加 28.4%） ) 和脂质（增加 34.7%）。相对于 RW，RR 提高了大团聚体（增加 56.0%）和微团聚体内颗粒有机碳（iPOC）（增加 13.0%）的比例，以及 SOC 含量（增加 12.7%）。结构方程模型表明，RR 可以通过提高 SOM 中小官能团的比例（NMR < 110 mg kg ^–1）和促进 SOM 化合物的形成来促进团聚体发育和 SOC 作为 iPOC 的存量，从而提高土壤 C 库的稳定性和含量相对于长期轮换中的 RW。