2种草本植物混播根系对土体抗剪强度的影响  

Effect of roots of two mixed sowing herbaceous plants on soil shear strength

作　　者：刘宇飞 赵燚柯 杨苑君 张立芸 刘武江 熊寿德 段青松 LIU Yufei;ZHAO Yike;YANG Yuanjun;ZHANG Liyun;LIU Wujiang;XIONG Shoude;DUAN Qingsong(College of Water Resources, Yunnan Agricultural University, 650201, Kunming, China;Kunming Land Development and Consolidation Center, 650100, Kunming, China;College of Mechanical and Electrical Engineering, Yunnan Agricultural University, 650201, Kunming, China;College of Resources and Environment, Yunnan Agricultural University, 650201, Kunming, China)

机构地区：[1]云南农业大学水利学院,昆明650201 [2]昆明市土地开发整理中心,昆明650100 [3]云南农业大学机电工程学院,昆明650201 [4]云南农业大学资源环境学院,昆明650201

出　　处：《中国水土保持科学》2021年第3期81-88,共8页Science of Soil and Water Conservation

基　　金：国家科技支撑项目“西南睦边扶贫区基本农田建设技术研究与示范”(2015BAD06B04);云南农业大学博士科研启动基金项目“混播草本植物根系固土能力机理”(A2032002468)。

摘　　要：为研究混播草本植物根系对土体抗剪强度的影响,选择合理的播种方式,强化草本植物固土效应,为生态环境建设提供科学依据,采用无侧限抗压强度试验,测算素土、单播紫花苜蓿(Medicago sativa)、单播非洲狗尾草(Setariaanceps stapf ex massey)、混播紫花苜蓿+非洲狗尾草(1∶1)根土复合体的黏聚力增量ΔC,测定根系特征值。结果表明:1)单播紫花苜蓿、单播非洲狗尾草、混播的根土复合体上层ΔC分别是素土黏聚力C值的125.93%、180.90%、235.42%,下层分别为62.82%、139.04%、183.04%。2)单播紫花苜蓿根系直径>1 mm的占85.80%,<0.2 mm的根系未观测到;单播非洲狗尾草根系直径均<0.6 mm;混播则在所有观测径级范围内都有分布。3)混播、单播非洲狗尾草的ΔC与破坏面根密度Rd、根面积比Rar和含根量Q间关系达显著或极显著,且与Q的相关性最高。混播根系土体的抗剪强度增量高于单播,可用Q预测混播草本根系的抗剪强度增量。[Background]Plant roots have a positive effect on improving slope stability and reducing soil erosion.Herbaceous sowing methods include single sowing and mixed sowing.Previous studies demonstrate that,compared with single sowing,mixed sowing is more beneficial to increasing the total coverage and the height of the grass belt,which in turn enhances the soil and water conservation effect.Therefore,the aim of this study is to explore effects and mechanism of mixed sowing herb roots in natural state improving shear strength of soil,so as to select a reasonable sowing method to strengthen the soil-fixing effect of herbaceous plants,and provide a scientific basis for ecological environment construction.[Methods]The experiment was carried out at the experimental farm of the Yunnan Agricultural University,China.In July 2017,a total of 40 PVC tubes,51 cm in length,110 mm in diameter and 3.2 mm in thickness,were all cut in half,and then the halves were bound together by pair with rubber bands.Upland red soil<5 mm in particle size was packed into the rubber-band-fixed tubes with the bottom sealed with plastic film up to 50 cm.The experiment was conducted with 4 treatments(10 samples for each):pure soil,Medicago sativa,Setariaanceps stapf ex massey,and mixture of M.sativa and S.stapf ex massey(1∶1).Six seeds were put in each tube,separately.In October 2018,out of each group,9 tubes were picked randomly,placed in water for 24 h until being fully saturated.Soil columns were taken out from the tubes.Shoots of the plants were cut off.The soil columns were cut into two,25 cm for each.From each half of the soil columns,a section of 20 cm in the middle was taken as test samples and the section was 10.36 cm in diameter.The saturation density of the samples were tested.Unconfined shear strength was tested on a SJ-1A type strain controlling triaxial apparatus.[Results]:1)ΔC(cohesion increment)in the upper layer of root-soil composite of single M.sativa,single S.stapf ex massey and the mixed sowing were 10.85,15.587 and 20.284 kPa,r

关 键 词：混播 草本植物 根系 无侧限抗压试验 抗剪强度增量 

分 类 号：S157.2[农业科学—土壤学]