The effects of grass hedgerow roots on shear strength and scouring resistance of root-soil complexes in the purple soil region

doi:10.11686/cyxb2020420

Abstract

Abstract:

Vegetated contour strips have significant effects on soil and water conservation on slopes， and the plant roots play a very important role. To explore the soil conservation properties of their root systems， we planted strips of two legumes （Dolichos lablab and Medicago sativa） at the Southwest University， Chongqing and the shear strength and scouring resistance of root-soil complexes were tested. To identify factors affecting mechanical properties， we imaged roots in grayscale， tested root chemical composition and mechanical properties and subjected data to correlation analysis. It was found that： 1） More than 90% of the root-soil complexes of M. sativa and D. lablab had a root diameter of less than 1.0 mm. The cellulose content of M. sativa complexes was significantly higher than that of D. lablab. The root length density， root surface area density and root volume density， and shear strength of complexes of D. lablab were more than those of M. sativa. 2） For the same diameter， the average maximum tension and tensile strength of D. lablab root complexes （19.76 N and 32.70 MPa， respectively） were more than those of M. sativa （14.32 N， 26.66 MPa）. The root diameter was positively correlated with ultimate maximum tension by a power function， and negatively correlated with tensile strength by power function. 3） The root systems of the two legume vegetation strips significantly （P<0.05） improved the cohesion and resistance， especially D. lablab vegetation strips. The average cohesion of D. lablab complexes was 22.88 kPa， which was 71.06% higher than that of the CK. And the scouring coefficient of D. lablab complexes was 19.00 L·g^-1， 2.60 times of that of the CK. 4） Principal component analysis showed that the root system traits that most affected the shear strength and scouring resistance of root-soil complexes were root length density， hemicellulose content and maximum tension. The comprehensive score of root-soil complexes of D. lablab vegetation strips was higher than that of M. sativa. In summary， the shear strength and scouring resistance of root soil complexes of D. lablab vegetation strips were better than those of M. sativa strips

Key words: Dolichos lablab, root length density, hemicellulose, maximum tension, cohesion, scouring resistance

Xiao-hong LIU, Yun CHEN, Zhe-hao YAN, Han TANG, Jiao-jiao QIANG, Yue QI, Yi-zhi DU. The effects of grass hedgerow roots on shear strength and scouring resistance of root-soil complexes in the purple soil region[J]. Acta Prataculturae Sinica, 2021, 30(11): 98-107.

Figures/Tables 7

References 27

1	Li J Q， Zhang H J， Cheng J H， et al. Soil physical properties of different hedgerow systems in upper reaches of Yangtze River. Chinese Journal of Applied Ecology， 2011， 22（2）： 418-424.
	黎建强，张洪江，程金花，等. 长江上游不同植物篱系统的土壤物理性质. 应用生态学报， 2011， 22（2）： 418-424.
2	Guo T， He B H， Jiang X J， et al. Effect of Leucaena leucocephala on soil organic carbon conservation on slope in the purple soil area. Acta Ecologica Sinica， 2012， 32（1）： 190-197.
	郭甜，何丙辉，蒋先军，等. 新银合欢篱对紫色土坡地土壤有机碳固持的作用. 生态学报， 2012， 32（1）： 190-197.
3	Zhai T T， Chen Y， Li T， et al. Comparative study on soil water reservoirs and shear strength between the sedimentation zone in front of and ridge behind hedgerows. Acta Ecologica Sinica， 2020， 40（2）： 599-607.
	翟婷婷，谌芸，李铁，等. 植物篱篱前淤积带与篱下土坎土壤水库和抗剪性能对比研究. 生态学报， 2020， 40（2）： 599-607.
4	Zhou P， Wen A B， Yan D C， et al. The mechanics of soil reinforcement by root on the hedge of the sloping cultivated lands of purple soils in the three gorges reservoir region. Journal of Soil and Water Conservation， 2017， 31（1）： 85-90.
	周萍，文安邦，严冬春，等. 三峡库区紫色土坡耕地草本植物根系固结地埂的土力学机制. 水土保持学报， 2017， 31（1）： 85-90.
5	Ding W B， He W J， Shi D M， et al. Effect of drying-wetting condition on attenuation-recovery of soil shear strength of bio-embankment on sloping farmland comprising purple soil. Acta Prataculturae Sinica， 2017， 26（6）： 56-67.
	丁文斌，何文健，史东梅，等. 干湿作用对紫色土坡耕地生物埂土壤抗剪强度衰减—恢复效应. 草业学报， 2017， 26（6）： 56-67.
6	Tang H， Chen Y， Liu X H， et al. Study on the mechanic features of root and root-soil matrix of Dolichos lablab hedgerows on the slopes of the Karst area. Acta Ecologica Sinica， 2019， 39（16）： 6114-6125.
	唐菡，谌芸，刘枭宏，等. 喀斯特坡地拉巴豆草篱根及根-土复合体力学特性. 生态学报， 2019， 39（16）： 6114-6125.
7	Osman N， Abdullah M N， Abdullah C H. Pull-out and tensile strength properties of two selected tropical trees. Sains Malaysiana， 2011， 40（6）： 577-585.
8	Giadrossich F， Schwarz M， Cohen D， et al. Mechanical interactions between neighbouring roots during pullout rests. Plant and Soil， 2013， 367： 391-406.
9	Zhou T， Chen Y， Wang R Z， et al. Effect of planting grasses and adding polyacrylamide on the shear performance and erodibility-resistance of purple soil in barren hillsides. Acta Prataculturae Sinica， 2019， 28（3）： 62-73.
	周涛，谌芸，王润泽，等. 种草和施用聚丙烯酰胺对荒坡紫色土抗剪和抗蚀性能的影响研究. 草业学报， 2019， 28（3）： 62-73.
10	Li T， Wang R Z， Chen Y， et al. Effects of polyacrylamide and grass root system on shear strength and physical properties of purple soil on barren slopes. Acta Prataculturae Sinica， 2018， 27（2）： 69-78.
	李铁，王润泽，谌芸，等. PAM和草类根系对荒坡紫色土物理性质与抗剪性能的影响. 草业学报， 2018， 27（2）： 69-78.
11	Boldrin D， Leung A K， Bengough A G. Root biomechanical properties during establishment of woody perennials. Ecological Engineering， 2017， 109： 196-206.
12	Li J， Wang X， Jia H X， et al. Ecological restoration with shrub roots for slope reinforcement in a shallow landslide-prone region. Acta Ecologica Sinica， 2019， 39（14）： 5117-5126．
	李佳，汪霞，贾海霞，等. 浅层滑坡多发区典型灌木根系对边坡土体抗剪强度的影响. 生态学报， 2019， 39（14）： 5117-5126.
13	Wang R Z， Chen Y， Li T， et al. Root distribution characteristics of Vetiveria zizanioides and Digitaria sanguinalis and their effects on the anti erodibility of purple soil in slope lands. Acta Prataculturae Sinica， 2017， 26（7）： 45-54.
	王润泽，谌芸，李铁，等. 香根草和马唐的根系特征及对坡地紫色土抗侵蚀性的影响. 草业学报， 2017， 26（7）： 45-54.
14	Xu W X， Bao Y H， Wei J， et al. Impacts of the typical herbaceous plant roots on soil scour resistance in the reservoir riparian zone. Journal of Soil and Water Conservation， 2019， 33（4）： 65-71， 109.
	徐文秀，鲍玉海，韦杰，等. 水库消落带典型草本植物根系对土壤抗冲性能的影响. 水土保持学报， 2019， 33（4）： 65-71， 109.
15	Liu Z， Yang R， Pei Y D. Soil erosion resistance characteristics of Zanthoxylum bungeanum and Lonicera japonica forest land in canyon areas of Karst plateau. Acta Pedologica Sinica， 2019， 56（2）： 466-474.
	刘志，杨瑞，裴仪岱. 喀斯特高原峡谷区顶坛花椒与金银花林地土壤抗侵蚀特征. 土壤学报， 2019， 56（2）： 466-474.
16	Baum W. Root system research method. Xue D R， Tan X L， translate. Beijing： Science Press， 1985： 231.
	伯姆 W. 根系研究法. 薛德榕，谭协麟，译. 北京：科学出版社， 1985： 231.
17	Chen Y， He B H， Lian C X， et al. Root-soil system anti-scourability on steep slopes in the Three Gorges Reservoir Area. Acta Ecologica Sinica， 2016， 36（16）： 5173-5181.
	谌芸，何丙辉，练彩霞，等. 三峡库区陡坡根-土复合体抗冲性能. 生态学报， 2016， 36（16）： 5173-5181.
18	Li H S. Experimental principle and techniques for plant physiology and biochemistry. Beijing： Higher Education Press， 2000： 211-212.
	李合生. 植物生理生化实验原理和技术. 北京：高等教育出版社， 2000： 211-212．
19	Lv C J， Chen L H. Relationship between root tensile mechanical properties and its main chemical components of tipical tree species in North China. Transactions of the Chinese Society of Agricultural Engineering， 2013， 29（23）： 69-78.
	吕春娟，陈丽华. 华北典型植被根系抗拉力学特性及其与主要化学成分关系. 农业工程学报， 2013， 29（23）： 69-78.
20	Makhlouf M， Aboul-Ezz A， Fayed M S， et al. Evaluating the amount of tooth movement and root resorption during canine retraction with friction versus frictionless mechanics using cone beam computed tomography. Open Access Macedonian Journal of Medical Sciences， 2018， 6（2）： 384-388.
21	Zhun M， Yan W， Luke M C M， et al. Mechanical traits of fine roots as a function of topology and anatomy. Annals of Botany， 2018， 122（7）： 1103-1116.
22	Ye C， Guo Z L， Cai C F， et al. Relationship between root tensile mechanical properties and main chemical components of five herbaceous specics. Pratacultural Science， 2017， 34（3）： 598-606.
	叶超，郭忠录，蔡崇法，等. 5种草本植物根系理化特性及其相关性. 草业科学， 2017， 34（3）： 598-606.
23	Zhang C B， Chen L H， Jiang J. Why fine tree roots are stronger than thicker roots： The role of cellulose and lignin in relation to slope stability. Geomorphology， 2014， 206： 196-202.
24	Mao Z， Jourdan C， Bonis M L， et al. Modelling root demography in heterogeneous mountain forests and applications for slope stability analysis. Plant and Soil， 2013， 363（1/2）： 357-382.
25	Li J X， He B H， Chen Y. Root features of typical herb plants for hillslope protection and their effects on soil infiltration. Acta Ecologica Sinica， 2013， 33（5）： 1535-1544.
	李建兴，何丙辉，谌芸. 不同护坡草本植物的根系特征及对土壤渗透性的影响. 生态学报， 2013， 33（5）： 1535-1544.
26	Xie K Y， Wang Y X， Wan J C， et al. Mechanisms and factors affecting nitrogen transfer in mixed legume/grass swards： A review. Acta Prataculturae Sinica， 2020， 29（3）： 157-170.
	谢开云，王玉祥，万江春，等. 混播草地中豆科/禾本科牧草氮转移机理及其影响因素. 草业学报， 2020， 29（3）： 157-170.
27	Yang Y M， Zheng Z C， Li T X. Soil anti-scourability dynamic variation characteristics and its influencing factors under different land use types. Journal of Soil and Water Conservation， 2010， 24（4）： 64-68.
	杨玉梅，郑子成，李廷轩. 不同土地利用方式下土壤抗冲性动态变化特征及其影响因素. 水土保持学报， 2010， 24（4）： 64-68.

试验名称 Test category	草篱种类 Grasses hedgerows	根系直径 Root diameter （mm）	根长密度 Root length density （×10^-3 cm·cm^-3）	根表面积密度 Root surface area density （×10^-3 cm²·cm^-3）	根体积密度 Root volume density （×10^-3 cm³·cm^-3）
抗剪 Shear resistance	紫花苜蓿 M. sativa	0.0<d≤1.0	553.34±18.33Aa	17.28±0.12Bb	0.56±0.02Ba
		1.0<d≤2.0	23.96±12.52Bb	10.06±1.11Bb	0.35±0.03Bb
		d>2.0	7.88±13.25Cb	40.62±5.58Aa	1.57±0.03Ab
		总体指标 Sum	585.51±19.66b	68.18±4.32b	2.47±1.38b
	拉巴豆 D. lablab	0.0<d≤1.0	565.54±18.99Aa	86.65±2.35Aa	0.48±0.08Cb
		1.0<d≤2.0	78.21±15.77Ba	36.28±4.32Ba	1.39±0.07Ba
		d>2.0	81.09±16.54Ba	46.28±1.97Ba	3.04±1.36Aa
		总体指标 Sum	725.04±15.33a	169.78±4.39a	4.97±1.38a
抗冲 Impact resistance	紫花苜蓿 M. sativa	0.0<d≤1.0	452.01±25.33Aa	29.68±7.25Ab	0.24±0.02Cb
		1.0<d≤2.0	18.45±2.36Ba	8.72±1.11Ba	0.34±0.05Ba
		d>2.0	34.74±6.78Ba	34.46±5.52Aa	0.49±0.04Aa
		总体指标 Sum	505.34±20.19a	81.75±6.63a	1.05±0.05a
	拉巴豆 D. lablab	0.0<d≤1.0	405.97±34.69Ab	35.76±4.21Aa	0.40±0.06Aa
		1.0<d≤2.0	19.79±3.55Ba	8.63±2.56Ca	0.31±0.03Ba
		d>2.0	20.40±4.23Bb	25.51±3.34Bb	0.40±0.02Aa
		总体指标 Sum	446.42±31.22a	77.67±5.21a	1.08±0.04a

试验名称 Test category	草篱种类 Grasses hedgerows	根系直径 Root diameter （mm）	根长密度 Root length density （×10^-3 cm·cm^-3）	根表面积密度 Root surface area density （×10^-3 cm²·cm^-3）	根体积密度 Root volume density （×10^-3 cm³·cm^-3）
抗剪 Shear resistance	紫花苜蓿 M. sativa	0.0<d≤1.0	553.34±18.33Aa	17.28±0.12Bb	0.56±0.02Ba
		1.0<d≤2.0	23.96±12.52Bb	10.06±1.11Bb	0.35±0.03Bb
		d>2.0	7.88±13.25Cb	40.62±5.58Aa	1.57±0.03Ab
		总体指标 Sum	585.51±19.66b	68.18±4.32b	2.47±1.38b
	拉巴豆 D. lablab	0.0<d≤1.0	565.54±18.99Aa	86.65±2.35Aa	0.48±0.08Cb
		1.0<d≤2.0	78.21±15.77Ba	36.28±4.32Ba	1.39±0.07Ba
		d>2.0	81.09±16.54Ba	46.28±1.97Ba	3.04±1.36Aa
		总体指标 Sum	725.04±15.33a	169.78±4.39a	4.97±1.38a
抗冲 Impact resistance	紫花苜蓿 M. sativa	0.0<d≤1.0	452.01±25.33Aa	29.68±7.25Ab	0.24±0.02Cb
		1.0<d≤2.0	18.45±2.36Ba	8.72±1.11Ba	0.34±0.05Ba
		d>2.0	34.74±6.78Ba	34.46±5.52Aa	0.49±0.04Aa
		总体指标 Sum	505.34±20.19a	81.75±6.63a	1.05±0.05a
	拉巴豆 D. lablab	0.0<d≤1.0	405.97±34.69Ab	35.76±4.21Aa	0.40±0.06Aa
		1.0<d≤2.0	19.79±3.55Ba	8.63±2.56Ca	0.31±0.03Ba
		d>2.0	20.40±4.23Bb	25.51±3.34Bb	0.40±0.02Aa
		总体指标 Sum	446.42±31.22a	77.67±5.21a	1.08±0.04a

处理 Treatments	竖直荷载Vertical load （kPa）				内摩擦角 Internal friction angle（°）	粘聚力 Cohesion （kPa）
处理 Treatments	100 kPa	200 kPa	300 kPa	400 kPa	内摩擦角 Internal friction angle（°）	粘聚力 Cohesion （kPa）
对照Blank control	55.10±3.32c	100.52±7.74c	136.33±10.14c	183.17±20.31c	22.78±2.57c	13.38±1.22b
紫花苜蓿M. sativa	71.59±2.64b	116.34±9.10b	168.39±5.27b	219.41±16.39b	26.10±2.33b	20.06±2.35ab
拉巴豆D. lablab	75.11±6.93a	131.22±4.11a	183.29±13.11a	235.69±17.21a	28.37±0.97a	22.88±0.92a

处理 Treatments	竖直荷载Vertical load （kPa）				内摩擦角 Internal friction angle（°）	粘聚力 Cohesion （kPa）
处理 Treatments	100 kPa	200 kPa	300 kPa	400 kPa	内摩擦角 Internal friction angle（°）	粘聚力 Cohesion （kPa）
对照Blank control	55.10±3.32c	100.52±7.74c	136.33±10.14c	183.17±20.31c	22.78±2.57c	13.38±1.22b
紫花苜蓿M. sativa	71.59±2.64b	116.34±9.10b	168.39±5.27b	219.41±16.39b	26.10±2.33b	20.06±2.35ab
拉巴豆D. lablab	75.11±6.93a	131.22±4.11a	183.29±13.11a	235.69±17.21a	28.37±0.97a	22.88±0.92a

试验名称 Test category	成分 Component	特征值 Eigenvalue	方差贡献率 Variance contribution rate （%）	X₁	X₂	X₃	X₄	X₅	X₆	X₇	X₈
抗剪 Shear resistance	F₁	5.057	63.212	0.945	0.241	-0.733	-0.966	0.845	-0.882	0.951	0.488
抗剪 Shear resistance	F₂	1.702	21.275	0.091	0.915	0.220	0.133	0.328	0.226	0.282	-0.743
抗冲 Impact resistance	F₁	4.207	52.583	0.951	0.293	-0.629	-0.945	0.814	0.149	0.914	0.638
	F₂	1.691	21.138	0.289	0.885	0.690	0.068	-0.057	0.196	0.301	-0.460
	F₃	1.371	17.137	-0.086	-0.344	-0.087	-0.043	0.385	0.896	-0.022	-0.533