Spatial characterization of iron oxides in hydric mineral soils

位于近地表地下水位地貌中的土壤，以及在局部洼地中发现的土壤，往往会经历较长或相对永久性的内涝时期。内涝减缓了氧气向土壤中的扩散；这很快就会导致厌氧条件，因为微生物继续呼吸有机物(主要来自植被)。在这样的土壤中，铁的溶解度可以通过化学还原以多种方式增加--这个过程被称为“潜水”。Gleying不仅改变了这些土壤的颜色(从黄红色变成灰蓝色)，还可能影响土壤结构的稳定性，养分和污染物在土壤中的移动，以及温室气体(如氨和甲烷)的微生物产生。目前的研究集中在利用高分辨率CT扫描仪来了解这种元素在局部化学过程中的作用。这项研究的第二部分将评估铁的分布(由CT扫描确定)对土壤磁化率的影响。这将有助于理解磁化率的现场测量，这是一种已被提议作为一种手段来描述GLEYED土壤的技术，用于特定地点的管理。

Soils located in landscapes with near-surface groundwater tables, as well as those found in localized depressions, frequently experience prolonged or relatively permanent periods of water logging. Water logging slows the diffusion of oxygen into the soil; this quickly leads to anaerobic conditions, as the micro-organisms continue to respire organic matter (originating primarily from vegetation). In such soils the solubility of iron may be increased manifold by chemical reduction - this process is called 'gleying'. Gleying not only changes the colour of these soils (from yellow-red to gray-blue), it may also influence structural stability, the movement of nutrients and pollutants through the soil, as well as the microbial production of greenhouse gases (such as ammonia and methane). The current research is focused on the utilization of a high-resolution CT scanner to understand the role of this element in local chemical processes. The second component of this research will evaluate the effect of the distribution of iron (as determined by CT scanning) on soil magnetic susceptibility. This will be useful for understanding field measurements of magnetic susceptibility, a technique that has been proposed as a means of delineating gleyed soils for site-specific management.