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Journal of Arid Land
Journal of Arid Land  2020, Vol. 12 Issue (4): 666-675    DOI: 10.1007/s40333-020-0017-6     CSTR: 32276.14.s40333-020-0017-6
Research article     
Untangling the influence of soil moisture on root pullout property of alfafa plant
Chaobo ZHANG1,*(), Yating LIU1, Pengchong LIU1, Jing JIANG1, Qihong YANG2
1College of Water Resources Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China
2Changjiang River Scientific Research Institute, Changjiang Water Resources Commission, Wuhan 430010, China
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Abstract  

Root pullout property of plants was of key importance to the soil reinforcement and the improvement of slope stability. To investigate the influence of soil moisture on root pullout resistance and failure modes in soil reinforcement process, we conducted pullout tests on alfalfa (Medicago sativa L.) roots at five levels (40, 30, 20, 10 and 6 kPa) of soil matric suction, corresponding to respectively 7.84%, 9.66%, 13.02%, 19.35% and 27.06% gravimetric soil moisture contents. Results showed that the maximal root pullout force of M. sativa decreased in a power function with increasing soil moisture content from 7.84% to 27.06%. Root slippage rate increased and breakage rate decreased with increasing soil moisture content. At 9.66% soil moisture content, root slippage rate and breakage rate was 56.41% and 43.58%, respectively. The threshold value of soil moisture content was about 9.00% for alfalfa roots in the loess soil. The maximal pullout force of M. sativa increased with root diameter in a power function. The threshold value of root diameter was 1.15 mm, because root slipping force was greater than root breaking force when diameter >1.15 mm, while diameter ≤1.15 mm, root slipping force tended to be less than root breaking force. No significant difference in pullout forces was observed between slipping roots and breaking roots when they had similar diameters. More easily obtained root tensile force (strength) is suggested to be used in root reinforcement models under the condition that the effect of root diameter is excluded as the pullout force of breaking roots measured in pullout tests is similar to the root tensile force obtained by tensile tests.

Key words： shallow landslides      root reinforcement      soil moisture content      threshold of root diameter      root pullout force      soil conservation     
Received: 16 December 2019      Published: 10 July 2020
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About author: *Corresponding author: ZHANG Chaobo (E-mail: zhangchaobo@tyut.edu.cn)
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Chaobo ZHANG
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Cite this article:

ZHANG Chaobo, LIU Yating, LIU Pengchong, JIANG Jing, YANG Qihong. Untangling the influence of soil moisture on root pullout property of alfafa plant. Journal of Arid Land, 2020, 12(4): 666-675.

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http://jal.xjegi.com/10.1007/s40333-020-0017-6     OR     http://jal.xjegi.com/Y2020/V12/I4/666

Fig. 1 Alfalfa (Medicago sativa L.) samples planted in containers (a) and root samples (b)
Fig. 2 Diagram of pullout test of alfalfa roots from the cultivation container
Fig. 3 Relationship between soil moisture content and soil matric suction
Fig. 4 Relationships of root slippage and breakage rates with soil moisture content
Fig. 5 Maximal root pullout forces under different soil moisture contents (a) and soil matric suctions (b). Different lowercase letters indicate significant differences among different soil moisture contents and soil matric suctions at P<0.05 level.
Root diameter
(mm)		 Root number of slippage Root number of breakage Root diameter of slippage
(mm)		 Root diameter of breakage
(mm)		 FP of slippage
(N)		 FP of breakage
(N)
D≤1.15 16 20 0.85±0.03a 0.76±0.04a 8.88±0.58a 9.79±0.53a
D>1.15 14 7 1.30±0.05a 1.36±0.05a 17.47±0.70a 18.23±0.92a
Total D 30 27 1.06±0.05a 0.93±0.06a 12.89±0.91a 11.98±0.85a
Table 1 Difference of root diameter (D) and the maximal pullout force (FP) between slippage and breakage of roots under 9.00% soil moisture content
Fig. 6 Relationships between the maximal root pullout forces of slipping and breaking and root diameter under 9.00% soil moisture content
Source Degree of freedom Mean square F P
SMC 4 35.319 32.703 0.008
D 92 14.896 13.793 0.025
SMC×D 15 2.670 2.472 0.248
Error 3 1.080
Total 114
Table 2 Summary of analysis of covariance for root diameter (D) and soil moisture content (SMC)
[1]   Abernethy B, Rutherfurd I D. 2001. The distribution and strength of riparian tree roots in relation to riverbank reinforcement. Hydrological Processes, 15(1): 63-79.
doi: 10.1002/(ISSN)1099-1085
[2]   Chang J M, Wang G Y, Hu S H, et al. 2018. Experimental study on effects of geometric characteristics of shrub roots on pulling force. Bulletin of Soil and Water Conservation, 38(6): 67-73. (in Chinese)
[3]   Cohen D, Schwarz M, Or D. 2011. An analytical fiber bundle model for pullout mechanics of root bundles. Journal of Geophysical Research: Earth Surface, 116: F03010.
[4]   Comino E, Marengo P. 2010. Root tensile strength of three shrub species: Rosa canina, Cotoneaster dammeri and Juniperus horizontalis: Soil reinforcement estimation by laboratory tests. Catena, 82(3): 227-235.
doi: 10.1016/j.catena.2010.06.010
[5]   Cui P, Lin Y M. 2013. Debris-flow treatment: The integration of botanical and geotechnical methods. Journal of Resources and Ecology, 4(2): 97-104.
doi: 10.5814/j.issn.1674-764x.2013.02.001
[6]   Dupuy L, Fourcaud T, Stokes A. 2005. A numerical investigation into factors affecting the anchorage of roots in tension. European Journal of Soil Science, 56(3): 319-327.
doi: 10.1111/ejs.2005.56.issue-3
[7]   Ennos A R. 1990. The anchorage of leek seedlings: the effect of root length and soil strength. Annals of Botany, 65(4): 409-416.
doi: 10.1093/oxfordjournals.aob.a087951
[8]   Fan C C, Tsai M H. 2016. Spatial distribution of plant root forces in root-permeated soils subject to shear. Soil & Tillage Research, 156: 1-15.
[9]   Fredlund D G, Xing A, Fredlund M D, et al. 1996. The relationship of the unsaturated soil shear strength to the soil-water characteristic curve. Canadian Geotechnical Journal, 33(3): 440-448.
doi: 10.1139/t96-065
[10]   Giadrossich F, Schwarz M, Cohen D, et al. 2017. Methods to measure the mechanical behaviour of tree roots: A review. Ecological Engineering, 109: 256-271.
doi: 10.1016/j.ecoleng.2017.08.032
[11]   Giadrossich F, Schwarz M, Cohen D, et al. 2013. Mechanical interactions between neighbouring roots during pullout tests. Plant and Soil, 367(1-2): 391-406.
doi: 10.1007/s11104-012-1475-1
[12]   Gray D H, Sotir R B. 1996. Biotechnical and Soil Bioengineering Slope Stabilisation: A Practical Guide for Erosion Control. New York: Wiley, 77-90.
[13]   Hales T C, Miniat C F. 2017. Soil moisture causes dynamic adjustments to root reinforcement that reduce slope stability. Earth Surface Processes and Landforms, 42(5): 803-813.
doi: 10.1002/esp.v42.5
[14]   Hallett P D, Newson T A. 2005. Describing soil crack formation using elastic-plastic fracture mechanics. European Journal of Soil Science, 56(1): 31-38.
doi: 10.1111/ejs.2005.56.issue-1
[15]   Harlan R L. 1973. Analysis of coupled heat‐fluid transport in partially frozen soil. Water Resources Research, 9(5): 1314-1323.
doi: 10.1029/WR009i005p01314
[16]   Ji X D, Cong X, Dai X Q, et al. 2018. Studying the mechanical properties of the soil-root interface using the pullout test method. Journal of Mountain Science, 15(4): 882-893.
doi: 10.1007/s11629-015-3791-4
[17]   Knapen A, Kitutu M G, Poesen J, et al. 2006. Landslides in a densely populated county at the footslopes of Mount Elgon (Uganda): Characteristics and causal factors. Geomorphology, 73(1-2): 149-165.
doi: 10.1016/j.geomorph.2005.07.004
[18]   Li S C, Sun H L, Yang Z R, et al. 2006. Mechanical characteristics of interaction between root system of plants and rock for rock slope protection. Chinese Journal of Rock Mechanics and Engineering, 25(10): 2051-2056. (in Chinese)
[19]   Liang T, Bengough A G, Knappett J A, et al. 2017a. Scaling of the reinforcement of soil slopes by living plants in a geotechnical centrifuge. Ecological Engineering, 109: 207-227.
doi: 10.1016/j.ecoleng.2017.06.067
[20]   Liang T, Knappett J A, Bengough A G, et al. 2017b. Small-scale modelling of plant root systems using 3D printing, with applications to investigate the role of vegetation on earthquake-induced landslides. Landslides, 14(5): 1747-1765.
doi: 10.1007/s10346-017-0802-2
[21]   Mickovski S B, Bengough A G, Bransby M F, et al. 2007. Material stiffness, branching pattern and soil matric potential affect the pullout resistance of model root systems. European Journal of Soil Science, 58(6): 1471-1481.
doi: 10.1111/ejs.2007.58.issue-6
[22]   Nan L, Shi S, Zhang J. 2014. Study on root system development ability of different root-type alfalfa. Acta Prataculturae Sinica, 23(2): 117-124. (in Chinese)
doi: 10.11686/cyxb20140214
[23]   Norris J E, Greenwood J R. 2008. An introduction to types of vegetated slopes. In: Norris J E, Stokes A, Mickovski S B, et al. Slope Stability and Erosion Control: Ecotechnological Solutions. Amsterdam: Springer, 9-15.
[24]   Pollen N, Simon A. 2005. Estimating the mechanical effects of riparian vegetation on stream bank stability using a fiber bundle model. Water Resources Research, 41: W07025.
[25]   Pollen N. 2007. Temporal and spatial variability in root reinforcement of streambanks: Accounting for soil shear strength and moisture. Catena, 69(3): 197-205.
doi: 10.1016/j.catena.2006.05.004
[26]   Schwarz M, Cohen D, Or D. 2010. Root-soil mechanical interactions during pullout and failure of root bundles. Journal of Geophysical Research: Earth Surface, 115: F04035
[27]   Schwarz M, Cohen D, Or D. 2011. Pullout tests of root analogs and natural root bundles in soil: Experiments and modeling. Journal of Geophysical Research: Earth Surface, 116: F02007.
[28]   Stokes A, Ball J, Fitter A H, et al. 1996. An experimental investigation of the resistance of model root systems to uprooting. Annals of Botany, 78(4): 415-421.
doi: 10.1006/anbo.1996.0137
[29]   Stubbs J C, Cook D D, Niklas J K. 2019. A general review of the biomechanics of root anchorage. Journal of Experimental Botany, 70(14): 3439-3451.
doi: 10.1093/jxb/ery451 pmid: 30698795
[30]   Vergani C, Giadrossich F, Buckley P, et al. 2017. Root reinforcement dynamics of European coppice woodlands and their effect on shallow landslides: A review. Earth-Science Reviews, 167: 88-102.
doi: 10.1016/j.earscirev.2017.02.002
[31]   Waldron L J. 1977. The shear resistance of root permeated homogeneous and stratified soil. Journal of the Soil Science Society of America, 41(5): 843-849.
doi: 10.2136/sssaj1977.03615995004100050005x
[32]   Wu T H. 1979. Strength of tree roots and landslides on Prince of Wales Island, Alaska. Canadian Geotechnical Journal, 16(1): 19-33.
doi: 10.1139/t79-003
[33]   Yildiz A, Graf F, Rickli C, et al. 2018. Determination of the shearing behaviour of root-permeated soils with a large-scale direct shear apparatus. Catena, 166: 98-113.
doi: 10.1016/j.catena.2018.03.022
[34]   Zhang C B, Zhou X, Jiang J, et al. 2019. Root moisture content influence on root tensile tests of herbaceous plants. Catena, 172: 140-147.
doi: 10.1016/j.catena.2018.08.012
[35]   Zhou Y, Watts D P, Li Y H, et al. 1998. A case study of effect of lateral roots of Pinus yunnanensis on shallow soil reinforcement. Forest Ecology and Management, 103(2-3): 107-120.
doi: 10.1016/S0378-1127(97)00216-8
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