紫色土区拉巴豆和紫花苜蓿根-土复合体抗剪性能研究  

Study on shear strength of root-soil composite of Dolichos lablab and Medicago sativa in purple soil region

作　　者：魏艳 刘有斌 刘枭宏 谌芸 颜哲豪 都艺芝 WEI Yan;LIU You-bin;LIU Xiao-hong;CHEN Yun;YAN Zhe-hao;DU Yi-zhi(College of Resources and Environment,Key Laboratory of Eco-environments in Three Gorges Reservoir Region,Southwest University,Chongqing 400715,China;Chengdu Water Conservancy and Soil Conservation Monitoring Center,Chengdu 610031,China)

机构地区：[1]西南大学资源环境学院,三峡库区生态环境教育部重点实验室,重庆400715 [2]成都市水利水保监测中心,四川成都610031

出　　处：《草业学报》2023年第8期82-90,共9页Acta Prataculturae Sinica

基　　金：国家自然科学基金(41501288);国家级大学生创新创业训练计划(202110635019);西南大学教育教学改革研究项目(2022JY074);西南大学科技创新“光炯”培育项目(202008)资助

摘　　要：为探究紫色土区草类根系对土壤抗剪性能的影响,以单播的拉巴豆、紫花苜蓿和裸地(CK)为对象,分析根系形态、纤维含量和抗拉力学性能,构建根-土复合体抗剪性能估算模型。结果表明:1)2种草根-土复合体黏聚力及不同荷载下的抗剪强度均高于CK,分别增强了141.30%~189.74%和1.18%~63.81%;2)2种草优势直径(d,mm)为0<d≤0.5径级,而在0.5<d≤1.0径级则表现为拉巴豆的根长密度、根表面积密度和根体积比均显著高于紫花苜蓿,分别高63.16%、62.50%和53.30%;3)黏聚力与根长密度呈显著正相关(R^(2)>0.710,P<0.01),与根长密度、极限延伸率拟合效果较好(R^(2)>0.900,P<0.01),模型预测值精度较高。总体上,紫色土坡地拉巴豆根系增强土壤抗剪性能效果优于紫花苜蓿根系。To clarify the effects of plant root systems on soil shear strength in purple soil sloping farmland,Dolichos lablab and Medicago sativa were planted and sampled.Their root morphological traits,fiber contents and biomechanical traits were measured.The shear strengths of root-soil composites were measured simultaneously.Correlation analysis and multiple stepwise regression analysis were used to analyze the relation between root traits(including fiber content)and soil cohesion,and root traits and soil internal friction.It was found that:1)Under 100,200,300,and 400 kPa vertical pressure,root-soil composite shear strengths of D.lablab and M.sativa were greater than CK by 1.18%-63.81%(P<0.05).Similarly,the soil cohesion with plant roots was 141.30%-189.74%greater than CK.2)For the dominant root diameter class≤0.5 mm,root parameters were the same for D.lablab and M.sativa.For root diameter classes>0.5 mm and≤1.0 mm,the root length density,root surface area density and root volume ratio of D.lablab were significantly greater than those of M.sativa.3)Soil cohesion in the root-soil composite showed a significantly positive relationship with root length density(R^(2)>0.710,P<0.01),and could be predicted well by root length density and ultimate elongation in a linear regression equation.Generally,D.lablab was better than M.sativa for root enhancement of soil shear strength in purple soil sloping farmland.

关 键 词：土壤侵蚀 根系 极限延伸率 抗剪强度 土壤黏聚力 

分 类 号：S157.433[农业科学—土壤学]