Organic matter stabilisation during paddy soil development depending on soil type

该项目的目的是确定微团聚体、有机矿物质复合体和烧焦的有机碳在稳定水稻土中有机碳方面的作用。物理(颗粒大小和密度)和化学分级相结合的方法将特别适用于每种土壤类型，以分离土壤类型特定土壤有机质(SOM)组分中的团聚体和有机无机复合体。然后，分离出的馏分将通过固态13C核磁共振波谱分析有机物的化学组成，特别是通过GC-MS分析可水解性碳水化合物的含量。选定组分中稳定有机物的年龄将通过放射性碳分析进行评估。有机矿物组合的特征是选择性或全部去除矿物和有机物，并结合比表面积分析。土壤组分将通过扫描电子显微镜和纳米SIMS进行研究，以阐明微团聚体和有机-矿物复合体的组成。这将使我们能够了解母质土壤类型对团聚体和土壤有机碳稳定作用的影响，例如依赖于铁氧化物的类型和含量，并评估不同的SOM稳定过程在水稻土形成过程中的贡献。

The aim of project is to identify the role of microaggregation, organo-mineral complexes, and charred organic carbon for the stabilisation of organic carbon in paddy soils. A method consisting of a combination of physical (particle-size and density) and chemical fractionation methods will be adapted to each soil type specifically to isolate aggregates and organo-mineral complexes in soil-type specific soil organic matter (SOM) fractions. The isolated fractions will then be analyzed for the chemical composition of the organic matter by solid-state 13C NMR spectroscopy and specifically for the hydrolysable carbohydrate content by GC-MS. The age of the stable organic matter in selected fractions will be assessed by radiocarbon analysis. The organo-mineral associations will be characterized by selective or total removal of minerals and organic substances in combination with analysis of specific surface area. Soil fractions will be investigated by SEM and NanoSIMS to elucidate the composition of microaggregates and organo-mineral complexes. This will enable us to understand the influence of the parent soil type on aggregation and soil organic carbon stabilisation in dependence of e.g. type and content of iron oxides, and to evaluate the contribution of the different SOM stabilisation processes during paddy soil formation.