Abstract Roots reinforce soil by acting as soil pins, dissipating shear stresses and anchoring the soil in place. By protruding into the soil and binding to soil particles, root hairs increase root-soil contact and aid root anchorage. However, it is not yet known whether this ability to anchor roots affects the root system’s ability to reinforce soil. Using a laboratory box shearing rig, this study explores whether root hairs affect soil shear resistance. The force required to shear soil columns permeated with roots lacking root hairs (barley brb and maize rth3 mutants) are compared to columns permeated with hairy roots (their respective wild types, WT) using unplanted soil columns as controls. Known root traits (e.g. root length density, root surface area density, average diameter, percentage of fine roots, and root tensile strength) were measured to ensure that differences in shear resistance could be attributed to the presence/absence of root hairs. All rooted columns required more force to shear than their respective unplanted columns but the thicker, stronger maize roots were more effective at soil reinforcement than the more numerous but weaker barley roots. After the maximum growth period, root hairs appeared to have a consistent and significant impact on peak shearing force. However, the WT root systems also produced greater root surface area density. As the rate at which peak shearing force increased with increasing root surface area density was similar for roots with and without root hairs, the increased peak shearing force of the WT columns cannot be attributed to resistance supplied by the presence of root hair but rather to a more prolific root system. Therefore, it was concluded that root diameter and root tensile strength most influenced root reinforcement of soil and as such, the relatively minute root hairs had negligible effects compared to their parent roots.

中文翻译：

---

大麦和玉米根的根毛在剪应力下会加固土壤吗？

摘要 根通过充当土壤销钉、消散剪应力和将土壤锚固到位来加固土壤。通过伸入土壤并与土壤颗粒结合，根毛增加根与土壤的接触并帮助根系固定。然而，目前尚不清楚这种锚定根系的能力是否会影响根系加固土壤的能力。本研究使用实验室箱式剪切装置探索根毛是否影响土壤抗剪力。使用未种植的土壤柱作为对照，将剪切渗透有缺乏根毛的根（大麦 brb 和玉米 rth3 突变体）的土壤柱所需的力与渗透有毛根的柱（它们各自的野生型，WT）进行比较。已知的根系特征（例如根长密度、根表面积密度、平均直径、细根百分比、和根部抗张强度）被测量以确保抗剪强度的差异可归因于根毛的存在/不存在。所有有根的柱子都需要比各自未种植的柱子更大的力来剪切，但较粗、较强壮的玉米根比数量较多但较弱的大麦根在土壤加固方面更有效。在最大生长期之后，根毛似乎对峰值剪切力具有一致且显着的影响。然而，WT 根系也产生了更大的根表面积密度。由于峰值剪切力随着根表面积密度的增加而增加的速率对于有和没有根毛的根是相似的，WT 柱增加的峰值剪切力不能归因于根毛的存在提供的阻力，而是更多产的根系。因此，可以得出结论，根直径和根抗拉强度对土壤的根系加固影响最大，因此，相对较细的根毛与其母根相比的影响可以忽略不计。