天然草本植被根系对表层土壤抗剪强度的影响  

Effects of wild herbaceous vegetation roots on undisturbed surface soil shear strength

作　　者：张惠忍 李法虎[1] 张心平[1] 

机构地区：[1]中国农业大学水利与土木工程学院,北京100083

出　　处：《中国农业大学学报》2015年第4期189-195,共7页Journal of China Agricultural University

基　　金：高等学校博士学科点专项科研基金(博导类)(20120008110024);国家自然科学基金重点项目(41230746);中央高校基本科研业务费专项资金(2013YJ009)

摘　　要：利用直剪仪在试验室测定了一年生天然草本植被（主要为稗草和狗尾巴草）根系特征参数对土壤-根系复合体抗剪强度的影响。结果显示,土壤-根系复合体抗剪强度与根重密度的相关性大于其与根长密度或根-土面积比的相关性。土壤-根系复合体抗剪强度随着土壤干密度和根重密度的增大而增大,但随土壤含水量的增大而减小。土壤干密度和土壤含水量对土壤-根系复合体抗剪强度的影响程度大于根重密度的影响程度,其与土壤-根系复合体抗剪强度的标准回归系数（Beta值）分别为0.456、-0.321和0.186。当根重密度为5-10kg/m^3时,一年生天然草本植被根系可增大土壤-根系复合体抗剪强度19.8%-39.5%。Current researches on soil slope protection with herbaceous vegetation are focused on the aboveground parts of vegetations.There is little knowledge on the role of vegetation roots.In this study,the effects of herbaceous vegetation root parameters on shear strength of soil-root composite were carried out by direct shear apparatus in laboratory on undisturbed soil samples collected at different growth stages of annual wild herbaceous vegetations.The investigated annual wild herbaceous vegetations mainly were Echinochloa crusgalli（L.）Beauv.and Setaria viridis（L.）Beauv..The results indicated that the correlation of soil-root composite shear strength with root weight density was greater than that with root length density or root-soil area ratio.The shear strength of soil-root composite increased with the increase of dry soil density and root weight density,but decreased with the increase of soil water content.The effect degrees of soil density or soil water content on soil-root complex shear strength was greater than that of root weight density.The standard regressive coefficients（Beta values）of root-soil composite shear strength with soil density,soil water content,and root weight density were 0.456,-0.321,and 0.186,respectively.A significant enforcement role was found for the annual wild herbaceous vegetation root system on soil-root composite shear strength.The wild herbaceous vegetation roots could increase soil shear strength by 19.8%-39.5% when root weight density was 5-10kg/m^3.

关 键 词：稗草 狗尾巴草 土壤-根系复合体 土壤含水量 直剪试验 

分 类 号：S157.2[农业科学—土壤学] TU411.7[农业科学—农业基础科学]