Aims

Recent laboratory studies revealed that root hairs may alter soil physical behaviour, influencing soil porosity and water retention on the small scale. However, the results are not consistent, and it is not known if structural changes at the small-scale have impacts at larger scales. Therefore, we evaluated the potential effects of root hairs on soil hydro-mechanical properties in the field using rhizosphere-scale physical measurements.

Methods

Changes in soil water retention properties as well as mechanical and hydraulic characteristics were monitored in both silt loam and sandy loam soils. Measurements were taken from plant establishment to harvesting in field trials, comparing three barley genotypes representing distinct phenotypic categories in relation to root hair length. Soil hardness and elasticity were measured using a 3-mm-diameter spherical indenter, while water sorptivity and repellency were measured using a miniaturized infiltrometer with a 0.4-mm tip radius.

Results

Over the growing season, plants induced changes in the soil water retention properties, with the plant available water increasing by 21%. Both soil hardness (P = 0.031) and elasticity (P = 0.048) decreased significantly in the presence of root hairs in silt loam soil, by 50% and 36%, respectively. Root hairs also led to significantly smaller water repellency (P = 0.007) in sandy loam soil vegetated with the hairy genotype (-49%) compared to the hairless mutant.

Conclusions

Breeding of cash crops for improved soil conditions could be achieved by selecting root phenotypes that ameliorate soil physical properties and therefore contribute to increased soil health.

中文翻译：

---

根毛对田间微尺度土壤物理性质的影响

目标

最近的实验室研究表明，根毛可能会改变土壤的物理行为，在小范围内影响土壤孔隙度和保水性。然而，结果并不一致，不知道小尺度的结构变化是否会影响更大的尺度。因此，我们使用根际尺度物理测量评估了根毛对田间土壤水力学特性的潜在影响。

方法

在粉砂壤土和沙壤土中监测土壤保水性以及机械和水力特性的变化。在田间试验中从植物建立到收获进行测量，比较代表与根毛长度相关的不同表型类别的三种大麦基因型。土壤硬度和弹性使用直径为 3 毫米的球形压头测量，而吸水性和排斥性使用尖端半径为 0.4 毫米的微型渗透仪测量。

结果

在生长季节，植物引起了土壤保水特性的变化，植物可用水增加了 21%。 粉质壤土中存在根毛时，土壤硬度 ( P  = 0.031) 和弹性 ( P = 0.048) 均显着下降，分别下降 50% 和 36%。 与无毛突变体相比，在有毛基因型 (-49%) 的沙壤土中，根毛也导致显着更小的防水性 ( P = 0.007)。

结论

通过选择能够改善土壤物理特性并因此有助于增加土壤健康的根系表型，可以培育经济作物以改善土壤条件。