This study discusses penetration resistance (PR) of forested Pumice-Andosol sites. PR, a key soil property influencing root growth and elongation, exerts a substantial influence on ecological site quality and tree growth. Andosols were expected to show low PR because of their unique characteristics (low bulk density, loose soil matrix). Five sites, two undisturbed and three backfilled, were sampled. The latter result from pumice excavation and were examined to quantify potential PR alterations in the aftermath of backfilling and pumice removal. Penetrologger sampling on undisturbed sites showed mean PR not exceeding 3 MPa, a literature-based, critical threshold restricting root growth, in the upper 0.80 m, indicating conditions fostering tree rooting. Backfilled sites mostly exhibited increased (> 3 MPa) PR, leading to rooting restrictions even beginning at −0.21 m. Deviations from undisturbed soils range from −15.6 to +109.3% depending on depth and age of the backfilled site. Furthermore, GIS-based data interpolation helped to identify spatial PR patterns and allowed a direct comparison before/after backfilling at one site. Statistical analysis revealed significantly altered PR after backfilling, while a concluding ANOVA provided at least significant governing factors (depth, area, clay + silt content, soil organic matter), albeit with only small effect sizes.

中文翻译：

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Laacher Seetephra Andosols的抗渗透性—评估德国西南部未受干扰和已发掘的森林土壤的生根条件

这项研究讨论了森林浮石-Andosol站点的渗透阻力（PR）。PR是影响根系生长和伸长的关键土壤特性，对生态位点质量和树木生长产生重大影响。由于其独特的特性（低堆积密度，松散的土壤基质），预计Andosols的PR较低。对五个地点进行了采样，其中两个未受干扰，三个已回填。后者是由浮石开挖产生的，经过检查以量化回填和浮石清除后潜在的PR变化。Penetrologger在不受干扰的地点进行的采样显示，平均PR不超过3 MPa，这是一个基于文献的限制根部生长的临界阈值，位于0.80 m的上部，表明有条件促进树木生根。回填场大部分表现出PR（> 3 MPa）增加，即使在-0.21 m处也导致生根限制。根据回填地点的深度和年龄，与未扰动土壤的偏差范围为−15.6至+ 109.3％。此外，基于GIS的数据插值有助于识别空间PR模式，并允许在一个站点回填之前/之后进行直接比较。统计分析表明，回填后PR发生了显着变化，而结论ANOVA至少提供了重要的控制因素（深度，面积，粘土+淤泥含量，土壤有机质），尽管影响范围很小。