Influence of the roots of mixed-planting species on the shear strength of saline loess soil

Liu, Yabin; Hu, Xiasong; Yu, Dunji; Hong, Zhu; Li, Guorong

doi:10.1007/s11629-020-6169-1

Cited by 14 publications

(15 citation statements)

References 30 publications

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“…In contrast, the coarse roots of woody plants can enhance both the soil's cohesion and its internal friction angle. This is because the lignification degree and the stiffness of the coarse roots of woody plants are greater than those of fine roots [54]. Compared with coniferous broad-leaved forest and grassland, the clay content of broad-leaved forest was the lowest, whereas the sand content was the highest, which was consistent with reported results [55].…”

Section: Discussionsupporting

confidence: 89%

Effects of Vegetation Type on Soil Shear Strength in Fengyang Mountain Nature Reserve, China

Liu

Cheng

Wang

et al. 2021

Forests

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Shear strength is an important mechanical property of soil, as its mechanical function plays critical roles in reducing land degradation and preventing soil erosion. However, shear strength may be affected by vegetation type through changes in the soil and root patterns. To understand the influences of different types of vegetation on shear strength, the soil shear indices of three typical vegetation types (broad-leaved forest, coniferous broad-leaved mixed forest, and grassland) were studied and evaluated at the Fengyang Mountain Nature Reserve, China. We employed a direct shear apparatus to measure the soil shear resistance index. We quantified the soil porosity, moisture content, and composition of particle size to determine the properties of the soil, and a root scanner was used to quantify the root index. The results revealed that there were significant differences in shear resistance indices at the stand level. Between the three vegetation types, the internal friction angle of the broad-leaved forest was the largest and the cohesion was the smallest. The soil moisture content and porosity of the coniferous broad-leaved mixed forest were higher than those of the broad-leaved forest, and the root volume density (RVD/cm3) of the broad-leaved forest was higher than that of the coniferous and broad-leaved mixed forest and grassland. Structural equation modeling results show that the soil particle size and root characteristics indirectly impacted the soil water content by affecting porosity, which finally affected shear strength. In general, there were significant differences in soil properties and plant root indices between the different stands, which had an impact on soil shear strength.

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Section: Discussionsupporting

confidence: 89%

Effects of Vegetation Type on Soil Shear Strength in Fengyang Mountain Nature Reserve, China

Liu

Cheng

Wang

et al. 2021

Forests

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“…In this study, the cohesion of rooted soil was greater than that of plain soil. This shows that root systems contribute to increases in soil cohesion (Jin et al, 2019; Liu et al, 2021). This additional cohesion is mainly caused by the mechanical resistance of the roots and the interfacial friction between the root system and soil particles (Zhou & Qi, 2018).…”

Section: Discussionmentioning

confidence: 98%

“…Specifically, plant roots prevent slope erosion mainly through the reinforcing effect of shallow fine roots and the anchoring effect of deep coarse roots (Docker & Hubble, 2009; Khairuddin et al, 2017). Huang et al (2021) found that the shear strength of rooted soil in collapsing walls first increased and then decreased with increasing root weight density (RWD), while cohesion linearly increased as root density increased (Liu et al, 2021). Soil is in direct contact and experiences friction with the root system, and it is also the key to realising the shear stress transformation and reinforcing soil by plant roots (Gray & Leiser, 1982).…”

Section: Introductionmentioning

confidence: 99%

Impact of Dicranopteris linearis roots on the shear strength of different soil layers in collapsing wall of Benggang

Zhou

Shuai

Chen

et al. 2022

European J Soil Science

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‘Benggang’ is a local term for a widespread type of severgully erosion with steep collapsing walls in granitic, low, hilly areas of southern China, and its development and expansion are closely related to the shear strength of the collapsing wall. Plant roots play an important role in improving soil shear strength. However, the shear strength of root‐soil complexes in different layers of collapsing walls remains obscure. We selected Dicranopteris linearis fern roots and adopted the direct shear method to evaluate the effect of root weight density (RWD) (0–1.25 g 100 cm−3) on the shear properties of the lateritic, sandy and detritus layers. The results showed that roots could enhance soil shear strength, and the maximum increase in the lateritic layer was 11.53%, higher than that in the sandy (5.84%) and detritus layers (3.17%). As the root content increased, the cohesion of the sandy and detritus layers increased and then decreased, and their maximum increase in cohesion and the fitting optimal RWD were lower than those of the lateritic layer. The internal friction angle was not affected by roots. When the root content was constant, the shear strength and cohesion of the lateritic layer were significantly higher than those of the sandy and detritus layers, while their internal friction angle was significantly lower than that of the latter two layers. The average increment of soil cohesion calculated by the Wu‐Waldron model (WWM) was 10.52 kPa, which was 0.30, 3.75 and 19.38 times the measured average values of the lateritic, sandy and detritus layers, respectively. The correction coefficient k′ was 0.02–1.18, and the truek'¯$$ \overline{k\hbox{'}} $$ in the lateritic layer was the highest (0.82), followed by that in the sandy and detritus layers. By combining the modified WWM with Coulomb's formula, new shear strength equations for root‐soil complexes of D. linearis were established. The predicted shear strength compared well with the measured shear strength (R2 > 0.90, NSE >0.90). Overall, the roots only had a significant reinforcement effect on the lateritic layer, and they could still not change the mechanical properties of the collapsing wall, which were more stable in the upper layers and weaker in the bottom. Therefore, other measures should be taken in the bottom layers to improve the stability of Benggangs. Highlights Effect of D. linearis roots on the shear strength of collapsing walls in Benggang was studied. Roots could improve collapsing‐wall soil shear strength, mainly reflected in the cohesion. The roots enhancement effect in lateritic layer was better than that of sandy and detritus layers. New shear strength equations of root‐soil complexes were established based on the Wu‐Waldron model.

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“…Root distribution related to root cohesion is reported mainly on woody plants in the Loess Plateau in the past decade [10,22,23]. In the past two years, herbaceous plants have been studied and the root distribution of several herbs introduced [24,25]. Root distribution characteristics including root area ratio, root number, root diameter, root cross-sectional area, root surface area and root volume have not been studied in detail.…”

Section: Introductionmentioning

confidence: 99%

Root Distribution and Root Cohesion of Two Herbaceous Plants in the Loess Plateau of China

et al. 2022

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In order to understand the root morphology distribution and mechanical properties of typical herbaceous plants, and to evaluate the ability of soil reinforcement by the plant roots, root morphology investigation, single root tensile test in laboratory and root cohesion evaluation by the Wu-Waldron model were carried out on two local representative herbaceous plants, Kochia scoparia (L.) Schrad and Artemisia sacrorum Ledeb. in the Loess Plateau of China. The results showed that the root morphological indexes (root number, single root diameter, root cross-sectional area, root surface area, root volume and root area ratio) of the two herbaceous plants decreased with the increase in soil depth, and the ratio of root to shallow soil layer was the highest in the 0–10 cm soil layer. The efficiency of root reinforcement could be higher in the shallow soil layer less than 10 cm. A positive correlation was observed between the root tensile force and root diameter in power function or exponential function, and a negative correlation was observed between the root tensile strength and root diameter in power function. The root cohesion of Kochia scoparia (2.73 kPa, or 0.92 kPa–1.37 kPa) was greater than that of Artemisia sacrorum (1.60 kPa, or 0.54 kPa–0.8 kPa), which could be used as the preferred herbaceous plant species for soil erosion control. The results could provide a scientific basis for selecting dominant species in the fields of ecological slope protection and soil and water conservation plant engineering in the loess area.

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Influence of the roots of mixed-planting species on the shear strength of saline loess soil

Cited by 14 publications

References 30 publications

Effects of Vegetation Type on Soil Shear Strength in Fengyang Mountain Nature Reserve, China

Effects of Vegetation Type on Soil Shear Strength in Fengyang Mountain Nature Reserve, China

Impact of Dicranopteris linearis roots on the shear strength of different soil layers in collapsing wall of Benggang

Root Distribution and Root Cohesion of Two Herbaceous Plants in the Loess Plateau of China

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