Root systems of native shrubs and trees in Hong Kong and their effects on enhancing slope stability

Leung, Flora T.Y.; Yan, W. M.; Hau, Billy Chi Hang; Tham, LG

doi:10.1016/j.catena.2014.10.018

Cited by 67 publications

(25 citation statements)

References 33 publications

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“…Schefflera heptaphylla, which is considered a robust species, can be commonly found in the secondary forests and scrublands of South China (Hau and Corlett 2002). The species has been recommended for landscape treatment in Hong Kong (GEO 2011) and has been used in local slope greening study (Leung et al 2011a(Leung et al , 2011b(Leung et al , 2015. The growth boxes, instrumented with tensiometers and moisture sensors, were exposed to an outdoor environment as well as an environmental chamber with controllable temperature and humidity.…”

Section: Introductionmentioning

confidence: 99%

Soil-water characteristics of compacted sandy and cemented soils with and without vegetation

Yan

Zhang

2015

Can. Geotech. J.

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Experiments were undertaken to study the soil-water characteristics of compacted sandy soil (SS) and cemented soil (CS) in field and laboratory conditions. The influence of vegetation and material density on the development of negative pore-water pressure (PWP) and degree of saturation (S r ) in the studied materials was investigated. The field planting experiments demonstrated a promising survival rate of Schefflera heptaphylla in both types of material, while the (SS) promoted better growth of the seedlings than the cemented one. In the field study, PWP and S r of the compacted SS responded noticeably and promptly to natural drying-wetting cycles. However, the responses in the CS were relatively mild. When subjected to the same dryingwetting cycles, PWP responded more slowly and to a smaller magnitude compared with that of the uncemented counterpart. In addition, S r changed little in CS. An increase in the density of the SS promoted rapid development of negative PWP, while an opposite trend was observed for CS. Attempts have been made to explain the observations from the perspectives of material permeability and change in water content during a drying period in both soil types. Furthermore, in SS, the development of PWP (with a measurement limit of −90 kPa) was minimally affected by the presence of vegetation, while vegetation noticeably helped the development of negative PWP in CS. Bounds of the soil-water characteristic curve (SWCCs) of the studied materials were presented based on estimates from the drying and wetting scanning curves derived from the field monitoring. A corresponding laboratory study was carried out in an environmental chamber with controllable temperature and humidity. Monitoring results from the laboratory agreed qualitatively with those obtained from the field.Résumé : Des expériences ont été réalisées pour étudier les caractéristiques de l'interaction sol-eau dans des sols sableux (SS) compactés et des sols consolidés (SC), sur le terrain et en laboratoire. On a analysé l'influence de la végétation et de la densité des matériaux sur l'augmentation de pression de l'eau interstitielle (PEI) négative et sur le degré de saturation (S r ) dans les matériaux étudiés. Les expériences de plantation sur le terrain ont mis en évidence un taux de survie prometteur de l'espèce végétale Schefflera heptaphylla dans deux types de matériaux, le sol sableux favorisant davantage la croissance des semis que le sol consolidé. Dans l'étude réalisée sur le terrain, la PEI et le S r du SS compacté a réagi de façon remarquable et rapidement aux cycles naturels d'humidification-assèchement. Cependant, les réponses des SC ont été relativement faibles. Lorsque ces derniers étaient soumis à des cycles d'humidification-assèchement identiques, la PEI a varié plus lentement et avec une amplitude moins élevée que dans le cas des sols non consolidés. En outre, S r a varié faiblement dans les SC. Une augmentation de la densité du SS a entraîné une augmentation rapide de la PEI négative alors que le phénomène inverse a é...

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Section: Introductionmentioning

confidence: 99%

Soil-water characteristics of compacted sandy and cemented soils with and without vegetation

Yan

Zhang

2015

Can. Geotech. J.

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“…The effect of root systems on controlling soil erosion mainly depends on the distribution and architecture of the roots (Li, Zhang, Geng, & Wang, ; Ye, Guo, Li, & Cai, ; Yu et al, ). The number of fine roots (<1 mm) largely controls soil detachment capacity (De Baets et al, ; De Baets, Poesen, Knapen, & Galindo, ; Leung, Yan, Hau, & Tham, ), which has been negatively correlated with root density (De Baets & Poesen, ; Zhang, Tang, & Zhang, ). Tap root systems have lower capacities to reduce soil detachment than fibrous root systems (De Baets et al, ; De Baets & Poesen, ; Zhang, Tang, Ren, & Zhang, ).…”

Section: Introductionmentioning

confidence: 99%

A comparison of the effectiveness of the roots of two grass species in reducing soil erosion on alluvial fans in south‐east China

Jiang

Lin

et al. 2019

Hydrological Processes

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The effects of root systems on soil detachment by overland flow are closely related to vegetation types. The objective of this study was to quantify the effects of two gramineous roots (Paspalum mandiocanum with shallow roots and Pennisetum giganteum with deep roots) on soil detachment capacity, rill erodibility, and critical shear stress on alluvial fans of benggang in south-east China. A 4-m-long and 0.12-mwide flume was used. Slope steepness ranged from 9% to 27%, and unit flow discharge ranged from 1.39 × 10 −3 to 4.19 × 10 −3 m 2 s −1 . The mean detachment capacities of P. mandiocanum and P. giganteum lands were 18% and 38% lower than that of bare land, respectively, and the effects of root on reducing soil detachment were mainly reflected in the 0-to 5-cm soil layer. The most important factors in characterizing soil detachment capacity were root length density and soil cohesion, and soil detachment capacity of the two grass lands could be estimated using flow shear stress, soil cohesion, and root length density (NSE = 0.90). With the increase in soil depth, rill erodibility increased, whereas shear stress decreased. The mean rill erodibilities of P. mandiocanum and P. giganteum lands were 81% and 61% as much as that of bare land, respectively. Additionally, rill erodibilities of the two grass lands could be estimated as an exponential function by root length density and soil cohesion (NSE = 0.88). The mean critical shear stress of P. mandiocanum and P. giganteum lands was 1.29 and 1.39 times that of bare land, respectively, and it could be estimated with a linear function by root length density (NSE = 0.76). This study demonstrated that planting of the two grasses P. mandiocanum and P. giganteum could effectively reduce soil detachment and enhance soil resistance to erosion on alluvial fans, with the deep roots of P. giganteum being more effective than the shallow roots of P. mandiocanum. The results are helpful for understanding the influencing mechanism of root systems on soil detachment process. K E Y W O R D Salluvial fan, benggang, gramineous plant, root, soil detachment, vegetation recovery

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“…Several studies investigated the effect of plant roots on slope stability as plants can reduce the risk of shallow landslides (e.g. Genet et al, 2010;Leung et al, 2015). Sliding of the top layer is also a possible mechanism of dike failure (Allsop et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Root properties of vegetation communities and their impact on the erosion resistance of river dikes

Vannoppen

Poesen

Peeters

et al. 2016

Earth Surf Processes Landf

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Root systems of native shrubs and trees in Hong Kong and their effects on enhancing slope stability

Cited by 67 publications

References 33 publications

Soil-water characteristics of compacted sandy and cemented soils with and without vegetation

Soil-water characteristics of compacted sandy and cemented soils with and without vegetation

A comparison of the effectiveness of the roots of two grass species in reducing soil erosion on alluvial fans in south‐east China

Root properties of vegetation communities and their impact on the erosion resistance of river dikes

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