Relationship between shear strength of Phragmites australis root-soil complexes and soil texture in aquatic-terrestrial ecotone
[Purpose]The aim of the study was to understand the effect of soil texture on the shear performance of Phragmites aust-ralis root-soil complexes and the relationship between them in the wetland aquatic-terrestrial ecotone.[Method]The root system of P.australis population naturally growing on different soil textures in wetland aquatic-terrestrial ecotone of Minjiang River was sampled to measure and analyze their distribution and morphology,and the differences in shear strength of root-soil complex.Combined with the physical properties of the soil,the grey correlation method and correlation analysis were used to analyze the factors affecting the shear performance of P.australis root-soil complex.[Result](1)The physical properties of different soil textures in the aquatic-ter-restrial ecotone varied greatly,significantly affecting the distribution and morphology of P.australis roots(P＜0.05).(2)Under the same soil depth of different soil textures in the aquatic-terrestrial ecotone,the cohesion force of sandy loam and loam soil was signifi-cantly greater than that of sandy soil(P＜0.05),and the internal friction angles were not significantly different among different soil textures(P＞0.05).(3)Through the grey correlation analysis,it was found that the main factor affecting the cohesion of P.australis root-soil complexes was soil porosity,and the grey correlation degree was 0.878.Soil water content was the most important factor af-fecting the internal friction angle,and the grey correlation degree was 0.921.(4)The shear strength of P.australis root-soil compos-ite was the best in sandy loam soil while the worst in sandy soil of wetland aquatic-terrestrial ecotone.[Conclusion]In different soil texture,the variation in shear strength of P.australis root-soil composite is obvious.Compared with sand soil and loam soil,the sandy loam soil has the highest shear strength with low density and high water content and porosity.
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