寒区公路不同坡度护坡土壤性状和群落特征及功能群差异

通过对G248公路高寒草原区红原县机场段的4个坡度（缓坡6°～15°、斜坡16°～25°、陡坡26°～35°、急坡36°～45°）护坡，进行土壤颗粒组成和理化指标、植被群落结构和优势种、功能群草种重要值等指标测定，研究坡度对物种种类、多样性、丰富度、均匀度及功能群重要值的影响。结果表明：坡度增加使土壤砂粒比例增大而粘粒和粉粒比例降低（P<0.05），含水量与有机质及有效N、P、K含量下降（P<0.05），使土壤易退化与沙化。坡度显著影响物种数、物种多样性、物种丰富度和物种均匀度和优势种种类、高度、比例及功能群植物的重要值（P<0.05），坡度越大群落密度、投影盖度和基盖度越低。故生态护坡建设应注意坡度对土壤沙化、植物种类及群落特征的影响。

Differences of Soil Properties,Community Characteristics and Functional Groups in different slopes of Highway Revetment in Alpine Region

To solve the practical technical problems of highway ecological slope vegetation construction,the highway revetment of 4 slope sizes (gentle slope 6°~15°,inclined slope 16°~25°,steep slope 26°~35°,heavy slope 36°~45°) in Hongyuan airport section of G248 highway were selected as the sample plots. By determined particle composition and physical and chemical indicators of the soils,vegetation community structure and dominant species characteristics,structural features and dominant species characteristics of the communitys,as well as important value of the functional groups,we studied the effects of slope sizes on species,diversity,richness,evenness and important values of functional groups. The results showed that:the aggravation of slope sizes increased the proportion of sand particles,decreased the proportion of silt particles (P<0.05),and decreased the contents of water content,organic matter and available N,P and K of soils (P<0.05),so causes soil degradation and desertification easily. Slope sizes significantly affected species number,species diversity,species richness and species evenness,as well as the species,height,proportion of dominant species and the important value of functional group plants (P<0.05). The greater the gradient,the lower the community density,projection coverage and basal coverage. Therefore,when constructing ecological slope protection,attention should be paid to the impact of slope on soil desertification,plant species and community characteristics.