To understand how climate change impacts soil fertility and ecosystem functioning, it is necessary to explore how different pools of soil organic matter (SOM) at aggregate scale are functionally affected in their molecular composition. Here, we collected rhizospheric soil at rice harvest from a paddy field in which a simulated climate change experiment was conducted for 6 years, including CO₂ enrichment up to 500 μmol mol⁻¹ (CE), air warming by 2 °C (WA), combination of CO₂ enrichment and air warming (CW), and the ambient environment as control. The soil samples were separated in three aggregate fractions (macroaggregates, 2000-250 μm; microaggregates, 250-53 μm; clay & silt, <53 μm) by wet sieving procedure, their molecular composition was detected by off-line pyrolysis gas chromatography mass spectrometry (GC/MS), and the analysis of microbial communities was conducted by phospholipid fatty acids (PLFAs). The mass proportion of macroaggregates increased by 32%, 55%, and 109%, while that of microaggregates decreased by 30%, 14% and 54%, compared to control under CE, WA, and CW treatments, respectively. The mass proportion of macroaggregates was significantly positively correlated with root biomass, while it was significantly negatively correlated in microaggregates, which suggested that the formation of macroaggregates was derived from microaggregates due to root entanglement, and/or mucilage. The molecular composition of SOM depleted in phenolic compounds (phenols and phenolic compounds) while accumulated in lipids (alcohols, alkanes/alkenes/alkynes and fatty acids) with decreasing aggregate size. The increased yields of lipids and phenolic compounds in macro-and microaggregates under CE treatment were likely related to the enhanced root litter, whereas they were reduced under WA treatment due to increase of fungal dominance. A lesser increment of those compounds was noticed under CW treatment and it was attributed to the antagonistic effect, in which the increment effect of CO₂ elevation can be counteracted by warming. The molecular composition hardly changed in clay & silt fraction under all climatic treatments, thus suggesting that the effect of elevated CO₂ and/or warming on SOM molecular composition faded with decreasing aggregate size. Shared by control and a climatic treatment, changes of common molecules in the whole soils depended on their distribution among aggregates. Moreover, the differences in common molecules distribution induced by climatic treatments were significantly correlated to those in mass proportion of aggregates. Considering that common molecules dominated the molecular abundance across all aggregate fractions, our findings indicate that the alteration of SOM molecular composition in the whole soils under climatic treatments appears to be modified by the variation in mass proportion of aggregates.

为了了解气候变化如何影响土壤肥力和生态系统功能，有必要探索总体规模的不同土壤有机质（SOM）分子组成如何在功能上受到影响。在这里，我们从稻田中收集了水稻收获时的根际土壤，在该稻田中进行了6年的模拟气候变化实验，包括CO ₂浓缩至500μmolmol ^-1（CE），空气升温2°C（WA） ，CO _2的组合浓缩和空气加热（CW），周围环境作为控制。通过湿法筛分将土壤样品分为三个聚集体部分（大聚集体，2000-250μm；微聚集体，250-53μm；黏土和淤泥，<53μm），并通过离线热解气相色谱质量检测其分子组成。光谱法（GC / MS），并通过磷脂脂肪酸（PLFA）进行微生物群落分析。与CE，WA和CW处理相比，大型骨料的质量比例分别增加了32％，55％和109％，而微骨料的质量比例减少了30％，14％和54％。大骨料的质量比例与根生物量显着正相关，而在微骨料中其显着负相关，这表明大团聚体的形成是由于根系缠结和/或粘液而从微团聚体衍生而来的。SOM的分子组成富含酚类化合物（酚和酚类化合物），而聚集在脂质（醇，烷烃/烯烃/炔烃和脂肪酸）中，且聚集体尺寸减小。在CE处理下，大型和微骨料中脂质和酚类化合物产量的增加可能与根凋落物的增加有关，而在WA处理下，由于真菌优势的增加，它们的产量下降。在连续波处理下，发现这些化合物的增加较少，这归因于拮抗作用，其中CO的增加作用 SOM的分子组成富含酚类化合物（酚和酚类化合物），而聚集在脂质（醇，烷烃/烯烃/炔烃和脂肪酸）中，且聚集体尺寸减小。在CE处理下，大型和微骨料中脂质和酚类化合物产量的增加可能与根凋落物的增加有关，而在WA处理下，由于真菌优势的增加，它们的产量下降。在连续波处理下，发现这些化合物的增加较少，这归因于拮抗作用，其中CO的增加作用 SOM的分子组成富含酚类化合物（酚和酚类化合物），而聚集在脂质（醇，烷烃/烯烃/炔烃和脂肪酸）中，且聚集体尺寸减小。在CE处理下，大型和微骨料中脂质和酚类化合物产量的增加可能与根凋落物的增加有关，而在WA处理下，由于真菌优势的增加，它们的产量下降。在连续波处理下，发现这些化合物的增加较少，这归因于拮抗作用，其中CO的增加作用 在CE处理下，大型和微骨料中脂质和酚类化合物产量的增加可能与根凋落物的增加有关，而在WA处理下，由于真菌优势的增加，它们的产量下降。在连续波处理下，发现这些化合物的增加较少，这归因于拮抗作用，其中CO的增加作用 在CE处理下，大型和微骨料中脂质和酚类化合物产量的增加可能与根凋落物的增加有关，而在WA处理下，由于真菌优势的增加，它们的产量下降。在连续波处理下，发现这些化合物的增加较少，这归因于拮抗作用，其中CO的增加作用₂升高可以通过加温来抵消。在所有气候处理下，粘土和淤泥中的分子组成几乎不变，因此表明了CO ₂升高的影响和/或SOM分子组成的变暖随着聚集体尺寸的减小而减弱。在控制和气候处理的共同作用下，整个土壤中常见分子的变化取决于它们在聚集体中的分布。此外，气候处理引起的常见分子分布的差异与聚集体的质量比例显着相关。考虑到常见分子在所有聚集体组分中占主导地位的分子丰度，我们的发现表明，在气候处理下，整个土壤中SOM分子组成的变化似乎被聚集体质量比例的变化所修饰。