We applied Fourier-Transformed Infrared Spectroscopy (FTIR) techniques in combination with selective humus extractions to investigate in situ the chemical features of organic matter in three soil profiles recently developed from Dutch sand dunes, under well-documented vegetation sequence and containing a relatively simple mineral-organic matter system. Water-soluble and alkaline-soluble extracts were also studied to match the changes of humus in the soil residues. Diffuse Reflectance Infrared Fourier Transform (DRIFT) and transmission spectra differed in resolution and sensitivity. DRIFT was superior in revealing structural information on the organic matter present in the soil samples whereas transmission spectra showed higher resolution for the bands of inorganic material at lower spectral frequencies. Differences between H and B horizons were due to the amount of hydrophilic organic acids, partly unsaturated, that were extracted by alkali. Extractable carboxylic acids and other hydrophilic compounds such as peptides and carbohydrates were larger in the less developed soils under pine and crowberry than in the more advanced profiles under beech. Humin residues from both H and B horizons retained unextractable aliphatic components and carboxylic groups involved in strong complexes with minerals, thereby confirming other findings that showed the largely aliphatic character of the unextractable humic fraction. Accumulation of poorly-soluble organic materials in these soils occur by protection from biodegradation due both to complexation with soil minerals and to a process by which apolar humic constituents form a separate hydrophobic phase where no biological activity can take place. Transport of poorly soluble compounds from H to B horizons, noticed especially in the more developed profiles, may have occurred through humic aggregates containing hydrophobic phases. This work shows that the DRIFT technique in combination with soil chemical treatments can be suitably employed to investigate the changes of organic matter in whole soil samples and represents a valid tool to investigate the role of organic matter in soil profile development.

中文翻译：

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主要植被序列下土壤有机质的红外光谱

我们将傅里叶变换红外光谱（FTIR）技术与选择性腐殖质提取技术结合使用，以有据可查的植被序列并包含相对简单的矿物的原位研究了最近从荷兰沙丘开发的三种土壤剖面中有机质的化学特征。 -有机物系统。还研究了水溶性和碱溶性提取物以匹配土壤残留物中腐殖质的变化。漫反射红外傅里叶变换（DRIFT）和透射光谱在分辨率和灵敏度上有所不同。DRIFT在揭示土壤样品中存在的有机物的结构信息方面表现优异，而透射光谱在较低的光谱频率下对无机材料的谱带显示出更高的分辨率。H和B层之间的差异是由于碱提取的亲水性有机酸（部分不饱和）的数量所致。在松树和越橘下欠发达的土壤中，可萃取的羧酸和其他亲水性化合物（如肽和碳水化合物）比山毛榉下较高级的土壤中的大。来自H和B层的腐殖质残留物保留了不可提取的脂族成分和与矿物形成牢固络合物的羧基，从而证实了其他发现，这些发现表明不可提取的腐殖质组分具有很大的脂族特性。这些土壤中难溶性有机物质的积累是通过防止与土壤矿物质络合以及非极性腐殖质成分形成单独的疏水相（其中不会发生生物活性）而防止生物降解而发生的。可溶性较差的化合物从H到B层的迁移（尤其是在较发达的剖面图中尤其明显）可能是通过含有疏水相的腐殖质聚集体发生的。这项工作表明，将DRIFT技术与土壤化学处理相结合可以适合用于研究整个土壤样品中有机物的变化，并且是研究有机物在土壤剖面发育中的作用的有效工具。特别是在较发达的剖面中注意到的，可能是由于含有疏水相的腐殖质聚集体引起的。这项工作表明，将DRIFT技术与土壤化学处理相结合可以适用于研究整个土壤样品中有机物的变化，并且是研究有机物在土壤剖面发育中的作用的有效工具。特别是在较发达的剖面中注意到的，可能是由于含有疏水相的腐殖质聚集体引起的。这项工作表明，将DRIFT技术与土壤化学处理相结合可以适用于研究整个土壤样品中有机物的变化，并且是研究有机物在土壤剖面发育中的作用的有效工具。