摘要
[目的]探讨退耕还林(草)工程实施20年以来,退耕地植物根系特征对土壤抗剪特性的影响,旨在为新时期黄土高原植被恢复和水土保持效益评估提供参考。[方法]选取黄土高原丘陵沟壑区不同演替阶段6个典型草地和2个人工草地,采集土壤表层(0—5 cm)土样120个,测定土壤抗剪特性、土壤性质和根系特征指标。[结果](1)各样地土壤容重无显著的差异(p>0.05),毛管孔隙度、总孔隙度和土壤含水量存在显著差异(p<0.05),其中人工草地毛管孔隙度和总孔隙度相对较小,白羊草样地土壤含水量最低。(2)不同演替阶段须根系植物根长密度和表面积密度较大在不同演替阶段均大于直根系植物,须根系植物根体积密度除演替初期外均小于直根系植物,人工草地沙打旺上述根系特征参数均不同程度小于自然撂荒草地。(3)各样地平均根土复合体抗剪强度相较于素土增加了22.11%~46.22%,但自然撂荒草地平均抗剪强度差异不显著(p>0.05)。人工草地黏聚力整体低于自然撂荒草地,不同演替阶段内摩擦角均表现为须根系植物大于直根系植物(1.07,1.25,1.23倍)。(4)黏聚力随总孔隙度(R^(2)=0.82)或根体积密度(R^(2)=0.47)的增加呈线性增大,内摩擦角随土壤容重的增加呈线性减少(R^(2)=0.39)。[结论]在植被恢复过程中,土壤性状、根系特征及根系构型对土壤抗剪特性有一定影响。
[Objective]The study aims to explore the impact of plant root characteristics on soil shear characteristics in typical abandoned farmland undergoing the‘Grain for Green’program over a period of 20 years,and to provide reference for evaluating the soil and water conservation benefits of vegetation restoration in the Loess Plateau during the new era.[Methods]Eight typical grasslands including six different successional stages and two artificial grasslands,were selected in the hilly and gully region of the Loess Plateau.Soil samples from the topsoil(0—5 cm)were collected,and measurements on soil shear characteristics,soil properties,and root characteristics were conducted to explore the influence of vegetation restoration on soil shear characteristics.[Results](1)There were no significant differences in soil bulk density among the sites(p>0.05).However,capillary porosity,total porosity,and soil moisture content exhibited significant differences(p<0.05).The artificial grassland had relatively lower capillary porosity and total porosity,and the Bothriochloa ischaemum(Linnaeus)Keng grassland had the lowest soil moisture content.(2)In different successional stages,the root length density and surface area density of fibrous root systems were generally higher than those of taproot systems.However,the root volume density of fibrous root systems was lower than that of taproot systems,except in the early successional stage.The artificial grassland(Astragalus adsurgens Pall.)exhibited lower values for these root characteristics compared to the natural fallow grassland.(3)The average shear strength of the root-soil complex increased by 22.11%to 46.22%compared to the bare soil,but the difference in average shear strength between natural fallow grassland and other grasslands was not significant(p>0.05).The cohesive force of the natural fallow grassland was generally higher than that of the artificial grassland,and the friction angle within different successional stages showed that fibrous root systems had higher values com
作者
田愉琴
王兵
汪建芳
白洁
Tian Yuqin;Wang Bing;Wang Jianfang;Bai Jie(Research Center for Soil and Water Conservation and Ecological Environment,Ministry of Education,Chinese Academy of Sciences,Yangling,Shaanxi 712100,China;State Key Laboratory of Soil Erosion and Drylandfarming on the Loess Plateau,Northwest A&F University,Yangling,Shaanxi 712100,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《水土保持研究》
CSCD
北大核心
2024年第3期153-159,共7页
Research of Soil and Water Conservation
基金
中国科学院“西部之光”西部青年学者项目(XAB2019A04)
国家自然科学基金重点项目(42130717)。
关键词
土壤性状
根系特征
黏聚力
内摩擦角
soil properties
root characteristics
cohesion
internal friction angle
