Direct characterization of soil P and fertilizer-soil reactions of recycling P-fertilizers by microspectroscopic methods

为了实现土壤的可持续施肥，有关土壤磷的化学状态和数量的信息是必要的。化学状态决定了植物对磷的可利用性，是肥效的关键参数。目前，还没有一种单一的分析方法可以直接检测土壤中的无机和有机P相。在本项目中，将开发和优化用于相关土壤分析的微光谱方法（x射线吸收近边结构（XANES）、深紫外拉曼和红外微光谱）。这些分析方法的结合将揭示土壤P状态的新线索，并将用于研究磷肥料-土壤的反应。一个重点将是分析新的循环磷肥及其在土壤-植物系统中的行为。该项目将与ETH z<e:1> rich（植物营养组）、Gießen大学（植物营养研究所）、南澳大利亚大学（环境风险评估和修复中心）以及柏林洪堡大学附属农业和城市生态项目研究所（IASP）等机构密切合作。这些结构分析方法将伴随农业盆栽试验。此外，还将进行DGT （Diffusive Gradient In Thin Films）和萃取实验，测定肥料和土壤样品中的生物可利用磷和不动磷。因此，用光谱方法直接在DGT结合层或萃取残留物上确定P的化学形态。这项广泛研究的结果将与农业伙伴密切合作进行分析，以解释磷肥-土壤-植物系统的转化机制，并使磷肥得到有效利用。

For sustainable soil fertilization, information about the chemical state and quantities of soil phosphorus (P) is necessary. The chemical state determines the plant-availability of the P species and is a critical parameter in fertilizer efficiency. Currently, there is no single analytical method that can detect inorganic and organic P phases directly in the soil. In the proposed project microspectroscopic methods (X-ray absorption near-edge structure (XANES), deep UV Raman and infrared microspectroscopy) will be developed and optimized for correlative soil analysis. The combination of these analytical approaches will shed new light on soil P states, and will be used to investigate P-fertiliser-soil reactions. One focal point will be the analysis of novel recycling P-fertilisers and their behaviours in soil-plant systems. The project will be conducted in close collaboration with institutions such as ETH Zürich (Plant Nutrition Group), University of Gießen (Institute of Plant Nutrition), University of South Australia (Centre for Environmental Risk Assessment and Remediation) and the Institute of Agricultural and Urban Ecological Projects affiliated to Berlin Humboldt University (IASP). Agricultural pot experiments will be accompanied by these structural analysis methods. In addition, DGT (Diffusive Gradient in Thin Films) and extraction experiments will be carried out to determine the bioavailable P and immobile P in fertilisers and soil samples. Therefore, the chemical form of P will be determined directly on the DGT binding layer or the extraction residues with spectroscopic methods. The results of this extensive research will be analysed in close cooperation with the agricultural partners to explain the transformation mechanism of the P-fertiliser-soil-plant system and to enable an efficient use of P-fertilisers.