Mechanical root reinforcement depends not only on root biomechanical properties but also on root biomass. Although it is known that plant spacing can affect root growth, it is not clear how it affects root tensile strength. We interpreted a set of field data to study the effects of spacing of Schefflera arboricola on root area ratio (RAR), root tensile strength and their combined effects on soil shear strength (also termed root cohesion). S. arboricola was transplanted into compacted silty sand at a spacing of 0.5 m, 0.8 m and 1.1 m. After 20 months of growth in the field, the root systems were excavated for root tensile testing and post-test trait measurements. Plant spacing affected the growth and tensile strength of roots. More closely spaced plants had higher RAR but lower root tensile strength, especially for roots 0.5–2 mm in diameter. According to the existing root breakage and fibre bundle models used in this study, which calculate root cohesion as the product of RAR and root tensile strength, the effects of plant spacing on root cohesion were minimal for most soil depths apart from 0.4- to 0.5-m depth.

中文翻译：

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株距对鹅掌柴根抗张强度和土壤抗剪强度的影响

机械根系增强不仅取决于根系生物力学特性，还取决于根系生物量。尽管已知植物间距会影响根系生长，但尚不清楚它如何影响根系抗张强度。我们解释了一组现场数据，以研究鹅掌柴的间距对根系面积比（RAR），根系抗张强度及其对土壤剪切强度的综合影响（也称为根系内聚力）。葡萄球菌将其以0.5 m，0.8 m和1.1 m的距离移植到压实的粉砂中。在田间生长20个月后，挖出根系用于根系拉伸测试和测试后性状测量。植物间距影响根的生长和抗张强度。间距较近的植物具有较高的RAR，但根系抗张强度较低，尤其是对于直径0.5–2 mm的根系。根据本研究中使用的现有根部折断和纤维束模型，这些模型计算出作为RAR和根部抗张强度的乘积的根部内聚力，在除0.4-至0.5-米深。