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

对于可持续的土壤施肥，有关土壤磷（P）的化学状态和数量的信息是必要的。磷的化学状态决定了磷的植物有效性，是肥料效率的关键参数。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磷和有机磷。在拟议的项目中，将开发和优化显微光谱方法（X射线吸收近边结构（XANES）、深紫外拉曼和红外显微光谱），用于相关的土壤分析。这些分析方法的结合将揭示土壤磷的状态，并将用于调查磷肥土壤反应。其中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。该项目将与苏黎世联邦理工学院（植物营养小组）、吉森大学（植物营养研究所）、南澳大学（环境风险评估和补救中心）以及柏林洪堡大学附属农业和城市生态项目研究所（IASP）等机构密切合作开展。农业盆栽实验将伴随着这些结构分析方法。此外，还将进行薄膜扩散梯度法和萃取法测定肥料和土壤样品中的生物有效磷和不动磷。因此，将直接在DGT结合层或浸提残留物上用光谱法测定P的化学形式。这项广泛研究的结果将与农业合作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，并使磷肥的有效利用成为可能。

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.