三峡库区紫色土坡耕地草本地埂植物根系分布及抗拉力学特征

Roots Distribution and Tensile Properties of Herbages on Hedge of Sloping Cultivated Lands of Purple Soils in Three Gorges Reservoir Region

[目的]探究三峡库区紫色土坡耕地3种草本地埂植物根系分布及抗拉特征,为揭示地埂植物根系固结地埂提供理论依据和数据支持。[方法]以三峡库区自然恢复的蓑草、人工种植的韭菜和蚕豆这3种草本地埂植物根系为研究对象,对比分析其根系在不同地埂土壤深度的分布规律及根系抗拉特性。[结果](1)在0—40cm深度土壤中3种草本地埂植物根系直径变化表现出:蚕豆根系>韭菜根系>蓑草根系。3种草本地埂植物根系直径与地埂土壤的土层深度间服从指数函数关系。(2)在0—40cm地埂土层深度范围内,韭菜根系生物量与蓑草根系和蚕豆根系生物量之间存在显著性差异(p<0.05),韭菜和蚕豆地埂植物根系生物量随土层深度的增加而逐渐减小,蓑草地埂植物根系生物量随土层深度的增加先增加后减小。(3)3种草本地埂植物根系的单根平均抗拉力次序为蚕豆根系(10.53N)>蓑草根系(6.03N)>韭菜根系(4.51N),3种地埂植物根系单根抗拉力与根径呈幂函数关系(p<0.05)。3种地埂植物根系的抗拉强度表现为蓑草根系(45.91 MPa)>蚕豆根系(18.02MPa)>韭菜根系(12.20 MPa)。(4)3种草本地埂植物根系黏聚力变化顺序为:蓑草根系(0.013 1kPa)>蚕豆根系(0.009 4kPa)>韭菜根系(0.005 5kPa)且3种地埂植物根系黏聚力与土层深度呈指数函数关系(p<0.01)。[结论]自然恢复的蓑草地埂在三峡库区较其他两种人工种植的地埂植物有更好的固结地埂效果,从而有效控制坡面土壤侵蚀和水土流失。草本植物固结地埂可为三峡库区坡耕地治理提供新思路。

[Objective] We aimed to illustrate the roots distribution and tensile properties of three herbages on the hedge of sloping cultivated lands of purple soils in Three Gorges Reservoir region, in order to supply the theory evidence and data supports for hedge consolidation with hedge plants.[Methods] One natural herbage, Eulaliopsis binata, and two artificial herbages, Allium tuberosum and Vicia faba were selected and their root distributions and root tensile properties in different soil depths were compared.[Results] （1） Diameters of the three herbages in 0-40 cm soil depth ranked as：V. faba 〉 A. tuberosum 〉 E. binata. Exponential function can be used to described their relationship between their diameter and the distributed soil depth. （2） There existed obviously significant difference between the roots biomass of A. tuberosum and the root biomass of V. faba and E. binata in 0-40 cm soil depth（p〈0.05）. Root biomass of A. tuberosum and V. faba were both decreased with the downward distribution in soil, but the root biomass of E. binata firstly increased then decreased with the increase of soil depth. （3） Mean root tensile force of the three hedge herbages ranked as：V. faba（10.53 N） 〉 E. binata（6.03 N） 〉 A. tuberosum（4.51 N）. And mean root tensile force was found dependent in power function upon root dimeter（p〈0.05）. Meanwhile, the rank of mean root tensile strength was E. binata（45.91 MPa） 〉 V. faba（18.02 MPa） 〉 A. tuberosum（12.20 MPa）. （4） The mean root cohesion of the three herbages ranked as：E. binata（0.013 1 kPa） 〉 V. faba（0.009 4 kPa） 〉 A. tuberosum（0.005 5 kPa）. And exponential relationship between mean root cohesion and soil depths was well fitted（p〈0.01）.[Conclusion] The natural hedge herbage of E. binata had better performances in soil reinforcement and soil conservation in this region, which could be used to effectively conserve soil and water from the sloping lands. And the herbage reinforcement of the hedge is a new idea for sloping cultivated land harness in the Three Gorges Reservoir region.