Soil–Water Interactions
Soil–Water Interactions
复制标题
DOI：
10.1002/9780470034590.emrstm1343
复制
发表时间：
2013-12
期刊：
影响因子：
--
通讯作者：
G. Schaumann;M. Bertmer
中科院分区：
文献类型：
--
作者：
G. Schaumann;M. Bertmer
质子核磁共振宽线光谱和低场弛豫测量是研究土壤-水相互作用的通用和非干扰工具。松弛计量学可以研究水的性质、在孔隙系统内的再分布(润湿)、孔隙大小分布及其随时间的变化(膨胀)。横向和纵向弛豫时间与扩散系数之间的二维(2-D)关联通过水的分子流动性、孔的连通性和凝胶相中的捕获等特征扩展了我们的知识。结合通过热分析获得的影响其冻结-融化行为的液态水的结构特征，这一多用途的洞察力允许识别有机物中的凝胶相，并了解高度膨胀的物质[如胞外聚合物(EPS)和粘液]对土壤结构、根际功能和团聚体特性的作用。质子宽线光谱可以在微观尺度上研究水和土壤有机质(SOM)片段之间的分子相互作用。在这些情况下，含质子物质的迁移率直接由线宽来反映。将这两种方法结合起来，利用有机物基质刚性的热表征信息，获得了关于超分子结构和水分子桥(WaMB)存在的信息。因此，这种方法是研究SOM矩阵中不稳定结构的最佳方法。关键词：土-水相互作用；溶胀；润湿；孔径分布；核磁共振弛豫法；宽线核磁共振；超分子结构；水分子桥
Proton NMR wideline spectroscopy and low-field relaxometry are versatile and nondisturbing tools for investigating soil–water interactions. Relaxometry allows studying the properties of water, redistribution within the pore system (wetting), pore size distribution, and its time-dependent changes (swelling). Two-dimensional (2-D) correlations between transversal and longitudinal relaxation times and diffusion coefficients extend our knowledge by features of molecular mobility of water, interconnectivity of pores, and entrapment in gel phases. Combination with structural features of liquid water affecting its freezing-melting behavior obtained by thermal analysis, this versatile insight allows to identify gel phases in the organic matter and to understand the role of highly swellable substances [such as extracellular polymeric substances (EPS) and mucilage] for soil structure, rhizosphere functions, and aggregate properties. Proton wideline spectroscopy allows studying molecular interactions between water and soil organic matter (SOM) segments on a microscopic scale. Mobility of proton-containing material is directly reflected by the linewidth in these cases. Combining the two methods and using information obtained from thermal characterization of the organic matter matrix rigidity, information on the supramolecular structure, and the presence of water molecule bridges (WaMB) are obtained. This method is thus optimal to study labile structures in the SOM matrix. Keywords: soil–water interactions; swelling; wetting; pore size distribution; NMR relaxometry; wideline NMR; supramolecular structure; water molecule bridges