坡度对高寒草甸公路护坡土壤性状及沙化表现的影响  

Effects of slope on soil properties and post construction desertification of highway embankments in an Alpine Meadow region

作　　者：郭碧花[1] 张雪梅[1] 刘金平[1] 游明鸿[2] 甘小洪[1] 羊勇 GUO Bi-hua;ZHANG Xue-mei;LIU Jin-ping;YOU Ming-hong;GAN Xiao-hong;YANG Yong(School of Life Sciences,China West Normal University,Nanchong 637009,China;Academy of Sichuan Grassland Science,Chengdu 611731,China;Sichuan Jiuma Highway Co.Ltd,Chengdu 611212,China)

机构地区：[1]西华师范大学生命科学学院,四川南充637009 [2]四川省草原科学研究院,四川成都611731 [3]四川久马高速公路有限责任公司,四川成都611212

出　　处：《草业学报》2022年第11期15-24,共10页Acta Prataculturae Sinica

基　　金：四川省交通运输科技项目(2019-ZL-19)资助。

摘　　要：针对高寒草甸公路护坡建设的实际技术需求,选择G248四川省红原县机场段,建成10年的5个坡度级(缓坡6°~15°、斜坡16°~25°、陡坡26°~35°、急坡36°~45°、峭坡>45°)公路护坡,通过测定土壤颗粒组成和理化指标、植被盖度和退化面积、有机质和全氮相对减少率等指标,分析不同坡度上土壤保水保肥能力、沙化等级比例组成及沙化表现差异,研究坡度对护坡土壤性状及沙化度的影响。结果表明:1)坡度升高显著降低黏粒和粉粒比例而增加砂粒和石砾比例(P<0.05),坡度越大土壤容重和pH值越大而含水量越低。2)坡度对土壤碳含量影响为有机质(SOM)>总碳(TC)>无机碳(IC)>溶解性有机碳(DOC),缓坡和斜坡使>70%的DOC和IC流失,斜坡和陡坡使约40%的SOM流失,急坡和陡坡使>90%的SOM和>60%的TC流失。3)坡度对土壤肥力影响为有效N>碱解N>全N>有效K>有效P>全K>全P,有效N比全N和碱解N更易流失,缓坡和斜坡下有效N流失最快,陡坡下全N和碱解N流失最快,全P和有效P仅在斜坡下流失,坡度升高会增加全K而降低有效K含量。4)坡度对沙化等级影响为极重度沙化(ED)>未沙化(ND)>中度沙化(MD)>轻度沙化(LD)>重度沙化(SD),斜坡下MD比例达52.46%,坡度>15°后增加SD比例,坡度>25°后ED比例快速增加。5)坡度>15°后沙化面积相对增加率几乎无变化,坡度>25°后有机质含量和全氮含量相对减少率变化较小,总盖度百分数和<0.02 mm粉粒相对减少率与>0.05 mm砂粒相对增加率随坡度显著增加。综上,不同坡度土壤粒级组成、养分流失程度、沙化度和沙化表现不同,故应依坡度大小制定相应的生态护坡建设技术方案。This research investigated effect of slope on the performance of highway embankment soil properties post construction,as there is a demand for technical data of this nature to underpin the design of highway revetment work in alpine meadow regions of China.A section of national road G248 in Northwest Sichuan Alpine Grassland,built 10years ago,was identified as a study site and plots were marked out for sampling on five slope classes:gentle slope,6°-15°(GS);moderate slope,16°-25°(MS);steep slope,26°-35°(SS);very steep slope,36°-45°(VS);extreme slope,>45°(ES).Undisturbed flat natural grassland>10 m distant from the roadbed was used as the control(CK).Measurements conducted included determination of particle size composition,physical and chemical parameters of the soils,vegetation cover and the proportion of the plot area exhibiting degradation or desertification.The relative reduction rate of organic matter and total nitrogen was also determined,and differences in soil water content and fertilizer retention capacity were assessed.It was anticipated these data would provide a basis for the construction of ecologically sound slope protection structures in alpine regions.It was found that:1)Increased slope significantly decreased the proportion of clay and silt particles and increased the proportion of coarse sand and small stones(P<0.05).The greater the slope,the greater the soil bulk density and pH value,and the lower the soil water content.2)Slope facilitated leaching of soil carbon fractions with the leaching intensity of the fractions ranking soil organic matter(SOM)>total carbon(TC)>inorganic carbon(IC)>dissolved organic carbon(DOC).For example,SOM levels were,respectively,115,92,72,30,9 and 3 mg·kg^(-1)for CK,GS,MS,SS,VS,and ES slope classes while DOC levels ranged from 35.4 mg·kg^(-1)in CK to 9.2 mg·kg^(-1)in ES.3)The ranking for the effects of slope on various soil fertility measures was:effective N>alkali-hydrolysable N>total N>available K>available P>total K>total P.Thus,available N was more easi

关 键 词：公路护坡 高寒草地 坡度 土壤沙化 沙化表现 

分 类 号：U417.12[交通运输工程—道路与铁道工程]