Increased silicon concentration in fen peat leads to a release of iron and phosphate and changes in the composition of dissolved organic matter
Increased silicon concentration in fen peat leads to a release of iron and phosphate and changes in the composition of dissolved organic matter
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DOI：
10.1016/j.geoderma.2020.114422
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发表时间：
2020-09-01
期刊：
影响因子：
6.1
通讯作者：
Schaller, Joerg
中科院分区：
文献类型：
--
作者：
Hoemberg, Annkathrin;Obst, Martin;Schaller, Joerg
先前的研究表明，硅（Si）增加了铁（Fe）磷酸盐的溶解，将磷（P）释放到沼泽泥炭的土壤溶液中，从而改变了有机质（OM）的组成。我们制定了三个问题上发生的过程：[i]高Si浓度是否会导致铁磷酸盐的动员？[ii]这种移动是否导致更高浓度的P、Fe和溶解有机碳？[iii]有机物的组成有变化吗？为此，在实验室条件下向泥炭中添加无定形二氧化硅，并利用X射线吸收光谱（XAS）分析了泥炭中Fe的矿物组成和碳质质量。此外，XAS数据表明，溶解的Fe（II）的磷酸盐和有机物的组成的变化与减少的贡献的羧基和quinones.We建议解释如下：在高Si浓度下的Fe（II）的磷酸盐溶解和有机物富含羧基被动员。随着土壤溶液中养分浓度的增加，有机质中醌类和羧基等氧化性组分的降解增强。
Prior studies have shown that silicon (Si) increases the dissolution of iron (Fe) phosphates, releasing phosphorus (P) into the soil solution of fen peat and thereby changing the composition of organic matter (OM). We formulated three questions on the occurring processes: [i] Does high Si concentration cause a mobilization of Fe phosphates? [ii] Does this mobilization result in a higher concentration of P, Fe, and dissolved organic carbon? [iii] Are there changes in the composition of organic matter?To this end, we conducted a laboratory experiment adding amorphous silica to fen peat and analyzed Fe mineralogy and carbon quality of the peat material by X-ray absorption spectroscopy (XAS).Under high Si concentration, significantly higher concentrations of P and Fe were found in soil solution. Moreover, XAS data indicated a dissolution of Fe (II) phosphates and a change in the composition of OM available to microbes with decreasing contributions of carboxylic groups and quinones.We propose to explain the effects as follows: under high Si concentration Fe (II) phosphates dissolve and OM rich in carboxylic groups are mobilized. As the nutrient concentration in the soil solution increased, the degradation of oxidized components of the OM, such as quinones and carboxylic groups is enhanced.