Micro-scale dry bulk density variation around earthworm (Lumbricus terrestris L.) burrows based on X-ray computed tomography
Micro-scale dry bulk density variation around earthworm (Lumbricus terrestris L.) burrows based on X-ray computed tomography
复制标题
基于 X 射线计算机断层扫描的蚯蚓 (Lumbricus terrestris L.) 洞穴周围微尺度干容重变化
DOI：
10.1016/j.geoderma.2013.08.034
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发表时间：
2014
期刊：
影响因子：
6.1
通讯作者：
H. Gerke
中科院分区：
文献类型：
--
作者：
H. Rogasik;S. Schrader;I. Onasch;J. Kiesel;H. Gerke
蚯蚓的挖洞活动导致土壤结构的变化，通过压实周围的土壤基质，这代表了所谓的drilosphere。这是一个独特的体积周围产生的大孔隙，控制各种土壤过程。为了检测洞穴周围的体积密度变化，从一个粉质壤土与定义的含水量和体积密度创建两个重新填充的土柱，分别接种非病原菌种蚯蚓，在恒定条件下储存7周，最后通过X射线计算机断层扫描分析。一个基本的体素的方法进行无间隙分析的drilosphere和周围的土壤基质。将测量的基本体素的亨氏单位（像素尺寸为0.25 mm，切片厚度为0.625 mm）转换为相应的干体积密度（BD）。整个水平土壤切片的初始平均BD为1.34 Mg m− 3（岩芯1）和1.38 Mg m− 3（岩芯2）。由于BurrowingL. terrestris压实drilosphere（洞穴壁）的内边界高达BD至少1.75 Mg m− 3，相当于土壤基质的30%以上。从内边界到外边界，即与周围土壤基质的过渡区，BD逐渐减小。然而，BD的减少是不同心均匀的，但显示不同的BD类区的异质模式。这种局部不均匀的BD分布是径向摩擦力各向异性作用的证据。我们的结论是，BD的不均匀性在drilosphere的L。terrestris可能有显着的影响，了解横向转移的水和溶质在土壤剖面。
The burrowing activity of earthworms leads to soil structural changes by compaction of surrounded soil matrix, which represents the so-called drilosphere. This is a distinct volume around the resulting macropore, which controls various soil processes. In the aim to detect the bulk density variation around earthworm burrows, two repacked soil columns from a silt loam with defined water content and bulk density were created, separately inoculated with the anecic earthworm speciesLumbricus terrestris, stored under constant conditions for 7 weeks and finally analyzed by means of X-ray computed tomography. A basic voxel approach was developed to conduct a gapless analysis of the drilosphere and surrounding soil matrix. The measured Hounsfield Units of basic voxels (pixel size of 0.25 mm and slice thickness of 0.625 mm) were converted into the corresponding dry bulk density (BD). The initial mean BD of an entire horizontal soil slice was 1.34 Mg m− 3(core 1) and 1.38 Mg m− 3(core 2). Due to burrowingL. terrestriscompacted the inner boundary of the drilosphere (burrow wall) up to a BD of at least 1.75 Mg m− 3which equates to more than 30% compared to the soil matrix. The BD decreased from the inner boundary of the drilosphere to its outer boundary, which is a transition zone to the surrounding soil matrix. However, the BD decrease was not concentrically uniform but revealed heterogeneous patterns of zones with different BD-classes. This locally heterogeneous BD distribution is an evidence of radial earthworm forces acting anisotropically. We conclude that BD heterogeneity in the drilosphere ofL. terrestrismight have notable implications for the understanding of lateral transfer of water and solutes in the soil profile.