Retention of dissolved organic matter (DOM) by short-range ordered aluminosilicates (SROAS) by adsorption and co-precipitation contributes to carbon accrual in soils and sediments. In this study, we investigated effects of SROAS composition on DOM adsorption, partitioning of carbon moieties by adsorption and co-precipitation, and the mineral structure of co-precipitates. We used four types of sorptive solutions, representing DOM collected in situ from topsoil and subsoil horizons of a Dystric Cambisol, and water-extracted DOM from beech and fir litter. We studied adsorption of soil DOM on three SROAS that structurally resemble proto-imogolites and Si-rich allophanes as a function of contact time (1–168 h) at initial pH 5. Co-precipitation of soil and litter-extracted DOM was quantified as a function of the molar Al:C ratio (0.3–1.4) and at two levels of Si concentration (molar Al:Si = 1 and 2). To resolve the impact of DOM on mineral structure, we first examined time-dependent structural evolution of SROAS within 1 to 72 h and subsequently investigated the effects of DOM interference in crystallization processes. Mineral structure of SROAS and co-precipitates was resolved by infrared, solid-state ²⁷Al- and ²⁹Si-NMR spectroscopy. Chemical composition of DOM prior to reaction with SROAS and in co-precipitates was analysed by solid-state ¹³C-NMR spectroscopy. Maximal C contents of adsorption complexes were 7.1 mg C g⁻¹ for Al-rich and 20.4 mg C g⁻¹ for Si-rich SROAS. We found selective adsorption of aromatic C and preferential exclusion of polysaccharide and alkyl C for both topsoil and subsoil DOM. Adsorption was larger for a Si-rich SROAS, since it exhibited a greater accessibility of aluminol groups. As a function of aromatic C content in initial DOM, 39.9 to 81% of C was retained by co-precipitation. Composition of co-precipitated organic matter was determined by C speciation in DOM supply, involving marked uptake of polysaccharides. In the absence of DOM, up to 50% of Si was present in imogolite-like configuration after 72 h, evidencing rapid development of short-range order. Complexation of Al by DOM during formation of SROAS caused partial exclusion of Si and slowed structural evolution, consequently enhancing abundance of ill-defied Si species in co-precipitates. Interactions of DOM with SROAS may cause selective accumulation of organic compounds and promote Si mobility in Andosols and Podzols.

短程有序铝硅酸盐 (SROAS) 通过吸附和共沉淀保留溶解的有机物 (DOM) 有助于土壤和沉积物中的碳积累。在这项研究中，我们研究了 SROAS 组成对 DOM 吸附、吸附和共沉淀对碳部分的分配以及共沉淀物的矿物结构的影响。我们使用了四种类型的吸附解决方案，代表原位收集的DOM来自 Dystric Cambisol 的表土层和下层土层，以及从山毛榉和冷杉垫料中提取的 DOM。我们研究了三种 SROAS 对土壤 DOM 的吸附，这些 SROAS 在结构上类似于原始伊毛缟石和富含硅的水铝英石，在初始 pH 值为 5 时作为接触时间（1-168 小时）的函数。土壤和枯枝落叶提取的 DOM 的共沉淀被量化为摩尔 Al:C 比 (0.3–1.4) 和两个 Si 浓度水平 (摩尔 Al:Si = 1 和 2) 的函数。为了解决 DOM 对矿物结构的影响，我们首先检查了 SROAS 在 1 到 72 小时内随时间变化的结构演化，随后研究了 DOM 干扰对结晶过程的影响。SROAS 和共沉淀物的矿物结构通过红外、固态²⁷ Al 和^29解析硅核磁共振光谱。通过固态¹³ C-NMR 光谱分析在与 SROAS 反应之前和共沉淀物中 DOM 的化学组成。吸附配合物的最大 C 含量为 7.1 mg C g ^-1（富铝）和 20.4 mg C g ^-1对于富含硅的 SROAS。我们发现表土和底土 DOM 都选择性吸附芳香族 C，优先排除多糖和烷基 C。富硅 SROAS 的吸附更大，因为它表现出更大的铝醇基团可及性。作为初始 DOM 中芳烃 C 含量的函数，39.9 至 81% 的 C 通过共沉淀保留。共沉淀有机物的组成由 DOM 供应中的 C 形态确定，涉及多糖的显着吸收。在没有 DOM 的情况下，高达 50% 的 Si 在 72 小时后以类似伊毛缟石的形式存在，证明了短程有序的快速发展。在 SROAS 形成过程中，DOM 与 Al 的络合导致部分 Si 被排除并减慢了结构演化，从而增加了共沉淀物中不良 Si 物种的丰度。