水陆交错带护坡植物固土抗蚀能力比较分析

Comparative analysis of soil reinforcement and anti-erosion capacity of slope protection plants in land-water ecotone

植物固土能力是生态护岸技术的关键影响因素,但对水陆交错带条件下的生态护坡植物固土能力的定量评估缺乏研究。选择耐旱耐淹且根系发达的芦竹、芦苇和风车草为研究对象,采用原位剪切试验和抗冲实验测定植物的抗剪切强度和土壤抗冲刷系数,对其固土能力进行综合比较,评价不同湿地植物的固土能力差别及其关键影响因子。结果表明:1)芦竹、芦苇和风车草均可显著提高土壤的抗剪强度和抗冲性能,抗剪强度增幅分别为111.80%、77.43%和99.17%,抗冲性能增幅分别为299.40%、140.21%和183.79%;2)芦竹的茎横截面积比例、根系生物量、根系密度和单位枝数的根数都显著大于芦苇和风车草;3)植物根系的平均直径、总体积和总数量与土体抗剪切强度正相关,根系生物量、根系密度、单位枝数根数、样方内植物茎横截面积比例与抗冲系数正相关。适生植物可显著提高水陆交错带土体的抗蚀能力,芦竹耐旱抗涝并具有较强的固土能力,可作为河岸、湖岸和库岸以及消落带等水陆交错带生态护坡的优选物种。

[Background]Ecological revetment is one of the protection technologies widely used in the stability of river banks,lakeshore,reservoir banks and water-level-fluctuating zones.The harsh land-water ecotone environment makes it challenging to choose appropriate plants for the purpose of ecological slope protection.The soil reinforcement capacity of plants is a key factor of ecological revetment technology.Quantitative assessment and comparison of the soil reinforcement capacity of wetland plants can provide a theoretical basis for ecological slope protection in land-water ecotone.[Methods]In this study,Arundo donax,Phragmites australis and Cyperus alternifolius,which are drought and waterlogging resistance and have well-developed root system,were selected as the material in this research.Soil anti-shearing strength and anti-scourability were determined by in-situ shear test and anti-scour tests,enabling us to compare and analyze the soil reinforcement capacity of the plants and the influencing factors.[Results]1)The results showed that A.donax,P.communis,and C.alternifolius significantly improved theanti-shearing strengthandanti-scourability,the anti-shearing strength of the three plants increased by 111.80%,77.43%and 99.17%respectively,and the anti-scourability increased by 299.40%,140.21%and 183.79%respectively.2)The proportion of stem cross-sectional area,root biomass,root density and root number per unit branch number of A.donax were significantly higher than those of P.communis and C.alternifolius.3)The analysis showed that the average diameter,total volume and total number of plant roots were positively correlated with the anti-shearing strength of soil.And the root biomass,root density,number of roots per unit branch and proportion of stem cross-sectional area in the quadrat were positively correlated with the anti-scourability of soil.[Conclusions]This study demonstrates that suitable plants can significantly improve the erosion resistance of soil in land-water ecotone regions.A.donax shows the strongest effects on soil reinforcement and has strong drought and waterlogging resistance,making it an ideal candidate for ecological revetment in land-water ecotone regions.